# Senn HD800 Ultimate, "Maxx" Mod



## Maxx134 (Sep 11, 2022)

In this thread,  we will progress from an hd800, to an HD800S, to extra mods, and finally discussion of my latest mods, the HD800M, & HD800SM...


As you may or may not know, I am the only person who "claims" to have corrected *ALL* the HD800 faults. The issue is, what are the faults?
So far, no one else I know has addressed the HD800, 800S, etc to has faults, except for lack of bass or too much trebles. That focus on tonality is not what is focused on here..
What I would consider real improvements are covered here.
Topics like 6k resonance/diffuse sound, and real driver Changes at end of thread, to increase driver performance. This is serious, not just a "tunning" mod.

 I had pioneered the resonance damping with the HD800 and now moved onto driver modification to increase performance further, posted later in this thread:
https://www.head-fi.org/threads/senn-hd800-ultimate-s-mod.879024/post-15489022



************************


*Onto the public mod:*

This is the "public" mod. It is the base for my, latest private mod, which is an evolutionary step over my resonance fixes or other  tunning mods.

I labeled it 800M & SM for the 800S version.
It has since been refined over 2yrs, and optimally I would like Sennheiser themselves to make it. It is mentioned in last pages of thread.
I will showcase it.


This first steps is an *HD800 to an 800S mod*, not a SDR mod.

*SDR* is popular because it is easy,  but remains only a tonality mod.
It *does not* correct the driver resonace or diffuse sound. It only tones Frequency down.
Tonality changes mods *are not* improvement mods. They are _*bandaid compromises*_.

In contrast, my mods are made as _*true solutions*_:

Preface:
 The public mod is called Ult "S" mod because I added my own center insert choice, which makes it very close to a 800S.

I will post some performance evidence first,
then followed by the procedures, and discoveries made alone the way...


*HD800 to an HD800S mod:*

Here is a initial comparison to an SDR mod, to show the difference in more upper FR (air), and more lows:







Stock also has more elevation than SDR, above 10khz.
This is why many internal mods kill the trebles and ambiance air of the soundstage.

Both mods were previously impossible to have without the 6k ringing(diffuse sound), but my  mod goes further to eliminate the "diffuse" nature.

More differences:
CSD:
30db down.




Notice that all decay is faster than .5ms (!),
all way down to 1k..
No 6kringing like stock and even 800S...
Clean CSD, unmatched by any HD800 or HD800S elsewhere (in regards to FR & decay).

Here is a screenshot of the best fabled never released annax mod:
pic




At 50db down a slight 1-2ms decay in trebles, (arguably the cleanest ever made)

Now here is mine 50db down:




(click to expand as looks too big to post large)
At a deep 50db down,
Fast decay of .05-1ms in WHOLE trebles range!
This is proof of no ringing(!)
This is unmatced by any modded HD800, or HD800S... ever before...

*Ringing*:
Here is a plain stock HD800, with actual ringing around 2.5k area, in CSD at 47db down. You can see the ripple peaks:




Here is this "Ult S" mod with zero ripples at same area, same 47db down:







*Distortion*:




Notice that the harmonics below noise floor,
And also to see is unique is the horizontal linearity of the harmonics.

In this one, the ambient noise was too high, so the white line (THD) reflects that,
and I removed the bass as debatable points because of the noise, but it was a gradual incline with the bass.
So the Bass measurements were too skewed because of the dam ambient noise so I will try update in future post.

One important point to note to make,
is that no other HD800 has ever had a linear distortion (no spike) in the trebles range,
and also stay below the noise floor... ever..(that I know )..
This is unmatched by any modded HD800, or HD800S.

Hear is my Impulse response:




First, It should be noted that this impulse, being the HD800, should be viewed already as a notably clean and noise free impulse response..
Small signal wiggles before the main peak, would reveals system distortion,
of which there are none here.

The main signal is the large first peak.
*There is Less negative overshoot than an 800 or 800S.
*The lack of a strong second upward spike after the initial transient is *very importan*t,
and is less than other HD800 or 800S...
This is said to indicates _*a more coherent sound, and superior imaging.*_

*The tighter rise & fall of the lines being tighter to the red line ( in this Mod), compared to stock,
is also indicative to cleaner response.
All below the 20 mark is already very good, especially if before 500ms.

*The smaller signals after the initial up and downward spikes,
are the ringing/reflection amplitudes of the enclosure,
of which is also better than any HD800 or HD800S.

*Suffice to say this Impulse response as a whole, is also unmatched, by any modded HD800, or HD800S.


*About this mod:*
Previously, there wasn't any mod available to make an HD800 sound similar, (but better) to an 800S...
So this was the goal... As you can see by my performance measure.

*No other HD800 or HD800S has this level of performance...*

Add to that, To also have the hallmark Sennheiser trebles and better bass than the 800S...

This mod WILL give you the bass, without the added blurry harmonics of the 800S(!).

This mod WILL preserve the treble "air" and signature Senn trebles, that other mods either kill off(rug liners & creatology foams) ..

This mod does supercedes the "Super Dupont" mod,
which flattens, tames, and even dulls out the upper trebles...In order to lessen the 6k resonance.
In past I was being polite to not admit the truth of my mods utter  superiority.

This mod CAN also be applied to the "Super Dupont" mod, in order to reduce ringing and keep that "SDR" signature of a tame HD800, if desired.

This is the only mod that eliminates the resonance problem WITHOUT killing, or neutralizing the trebles that all other tunning mods do.

*This is an all unique mod comprising of nobody else tweaks, liners, etc..*
It was a year long project that me and another member @ Olegausa  finished years ago,
so is about high time it gets revealed.

EDIT:
Some more measurements...

Comparisons of this mod to another HD800SD with StephanAudio hardwired:


This is a "clarity" tab in REW.

Next:

This is the "distortion" tab in REW showing the red line (2nd harmonic) distortion go up around treble region, which is one indicator of the HD800 treble resonance this mod solves...
Notice this mod on right side devoid of such elevated distortion.

Next:

This is the "Filtered IR" tab in REW.
Here we see in numerical value, the "clarity C50 & C80" results.

As you can see, the C80 measurement is the one to look at.

On a plain or SDR moded HD800, expect to see 19-20 or lower.

This mod's "C80 clarity" at 56, is more than double of the original HD800, even with a center driver mod like SDR.


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## Maxx134 (Oct 13, 2018)

im on lunch...


Ok ready?

STANDARD WARNING BEFORE PROCEED..
THIS THREAD CONTAINS INFO THAT WILL VOID YOUR WARRANTY (bla bla Of course).

AND MAY BE DIFFICULT FOR YOU TO REVERT, AND POSSIBLY DAMAGE YOUR HD800 IF NOT DONE CORRECTLY ...( if your a klux, which your not, and even if you were that wont stop you, right?)

USE MATERIALS/PROCEEDURE AS SUGGESTED FOR SUCCESS!

ONLY REASON I POST THIS STANDARD CRAP IS SO I WILL NOT BE HELD RESPONSIBLE AS YOU HAVE BEEN FOREWARNED..
NOW ONTO THE MODS....

This mod will retain and preserve "presence" and treble air without fatigue,
as the resonance is Eliminated!!!
All while the upper trebles range is preserved without the inherent dips of the 800 or 800S.

Once completed, you will now have now a more focused solid sound with more full and palpable  bass(!) Than either stock 800 or 800S..

This is THE ONLY Ultimate 800"S" mod in existence.

Upon completion,
You will now have the deepest and best quality HD800 bass.

You will have most *lazer sharp* imaging sounding of any the HD800 mods.

It WILL NOT kill Soundstage(!)...
Thats the big pink elephant in the room,
That many deny,
in their quest for a flatter frequency response...

Specifically, many other HD800 mods( by the inherent usage of special rug liners, fillers, or other materials)...

They all work by covering up or filling up the inside(!),
so they all have the side effect of killing the spaciousness and soundstaging,
Which is the hallmark of the HD800.
This approach, is more accurately described,
as "absorbtion".

After trying those other "great" methods, I was unsatisfied after initial joy of ""treble peak" loss,
As I found the signature overall sonically dead and not as lively, in all moded 800 versions..

This forced me to chose another path.
Instead of absorbtion, we go to the root of the resonance problem,
to stop it with dampening, not absorbtion.
Sound damping, and sound absorbtion are two very very different things.

That way, we preserve more of the HD800 Soundstage, by keeping interior dimensions untouched and spacious,
and also keeping the upper frequency range preserved,
which is responsible for treble "presence" and "air"...

It is also already proven (in another site), that the HD800 driver Frequency Response is actually smooth, when tested apart from its enclosure.

This aludes to the obvious problem of the enclosure.
A problem that STILL has not been adressed.
So the solution was damping.
Just like the HD650 was later proven(in another site) to improve with dampening.

Due to the complexity of the HD800 design, it was never considered or accomplished successfully untill now..

*****************

*List of all modifications:*

*Sonic Mods:*

*1-*"BASS Pressure/COUPLING SEAL" MOD*.
specific material to slow down the bass pressure from escaping pads
sub-bass seal and Impact preservation, inserted to the inside of ear pads.

*2-rear grill *Anti-reflection mod*,
This is accomplished by using specific deflective material by grill.
Yes those mesh metal screens in rear affect sound,
but you don't have to take them off (idiot approach).
No grill removal is necessary, as other mods, and this solves listener fatique from rear reflections.

*3- Rear dampening *Anti-resonance mod*.
(done after first 2)
This is a specific resonance killing material,
on specific areas in back of driver.***
Not any will do!

*4- *Metal ring replacement Mod.*
(Done Only after 1-3).
The driver edge metal ring is removed and replacement with a vibration damping ring and felt cover.
The problem in the past was that it was not thought out, and done alone...
Done alone solves nothing, just like trying to clap with one hand.
You need equal and opposing mass, which is the* Anti-Resonance Mod*.

*5- The* 800"S" Resonator Mod.
This is a hot item, get it while still in production.*
Before "you-know-who" hears about it, and discontinues it!

*Supplemental Mods:*
*6- *Internal wiring replacement mod*.
Replacement here is like a magnifying glass effect.
Care must be taken in replacement wire selection,
as this WILL affect the headphone signature tonality,
 from sweet to dark, but not in a FR way. In a cable sense way.

My advice is to *NEVER* replace, unless you're sure.
This is *an HD800 modding secret* unknown before.
That the internal wire has both an actual resistance and sonic aspect.
Stock internal wiring preserve sweeter sense, so recommendations at end.

*7-installation of* mini XLR connectors..

END OF MODS
****************************


One more note before Mods:
IMHO the SD mod insertion, is the most neutral version.
It is actually the most Excellent for neutrality.

Compared to this "S" mod, the SD mod is a more tame (less lively) sound.

So Mod number 5,  is for those that prefer the 800S type signature,
for a more " full ",lively or engaging sound.

For those that like their more linear "SD" Mod signature,
you can still implement all other mods listed here,
 to elevate your SD mod to a clearer, higher level.
As the "SD" mod only adresses the Frequency Response signature (6k & trebles elevation).

Actuall Mods Next..


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## Maxx134 (Sep 11, 2022)

Now onto the Mods:
To DO IN ORDER, VERY IMPORTANT.

*Sonic Mods:*
*1-*subbass mod*.
*2-*rear grill anti-reflection mod*,
using micro liner by grill
*3- *Rear dampening Anti-resonance mod*.
(do after 2)
*4- *Metal ring replacement Mod*.
(Do Only after 1-3).
*5- *The 800"S" Resonator Mod*.

Supplemental Mods:
*6- *Internal wiring replacement mod*.
*7--installation of *mini XLR connectors*.


Disclaimer,
These mods not for the faint-hearted.
Try at your own risk and it helps if your have some competence in modding and patience.

*************************************************************
EDIT:
This whole pad mod has been updated, to instead, to using the *Dekoni ferenstrated lambskin pads*, combined with a Specific silicone seal, extracted  from a cheaper but nice non-senheiser replacement pad, which is mentioned further in the thread.
Here is pic of the required silicone (plastic) seal:




So continue to the below method, _only_ if  you are using stock pads:

1- First off,
is the  *"BASS Pressure/COUPLING SEAL" MOD*
Take about an 8" long & 1" wide "rubber tape", and fold in half.
*Pic*





*pic*





*pic*
Insert into pads, working your way around the inside,
keeping the rubber flat,
without crushing the tape into a roll:







*pic*





*pic*





Sonic results are an increase in the bass "seal", providing a more palpable presence of the subsonics, not noted in measurements, and so the air pressure/ bass feel of impact  escapes less thru the foam pads.

This mod is easily reversable.
The tape has no adhesive, and only sticks to itself when folded in two,
Which matches the with of interior pad flap.

When tucked nicely inside, it gives a gentle lift to the pads.
It prevents the older pads "sag" &  collapse, and keeps the "new pad" feel and lift, for better soundStage as well.

Once settled they feel normal.
It gives a more solid coupling to face,
so less bass impact is dissapated out of the cloth pads.

Next steps involve pulling off the pads and opening unit, which is why we did this one first.

******************


2nd- *REAR GRILL ANTI-RELECTION MOD.*
Next mods involve the dismantle of the unit, and while not hard at all, still I will assume you already know how to do this.
Pull off pads,
Unscrew the ring but be careful as the rear plastic assembly will come off,
so hold unit together and gently remove plastic rear which house the rear grill.
Carfully slide out rear grill & plastic while holding driver unit to its base.

You will be using a micro sized "shelf liner" by the grill.
It is easily attainable at stores.
Cut shapes of thin shelf liner
*pic*




Insert by grill and leave rear of unit open for next mod...
Make sure the "liner" looks like this:




This will erradicate listening fatigue due to reflection of Upper frequencies.



This is both absorbtion and but more fine knit for dispertion (instead of the metal reflection) without killing soundstage and clearing depth.
This is suggested also to improve all 800 mods.


******************


3rd- the *Rear Dampening,  Anti-resonance mod:*
This most important mod will require the most skill and competence, or just patience.
This is *THE* mod to improve the SD mod as well.

The specific choice and layout of materials is very important.
We will be using Only
"*DYNAMAT EXTREME*"...(!)

VERY VERY IMPORTANT IS THE SPECIFIC USAGE OF THE  "EXTREME" VERSION OF DYNAMAT ONLY...
Do not use normal dynamat, or other brands, which are noted to be thinner.
Do not believe claims of better materials either, as that is not key.

We specifically need the thickest possible, for a specific reason which is "mass loading".

The objective here is to "mass load" the rear area of the driver coupling to the basket...
This application of the physical vibrational control of the structure, which will shift and eliminate the structure's resonance problem.

This is not "absorbtion" of existing sound. This is vibration attenuation thru deadening AND  Mass loading.
This is accomplished with use on both sides of driver, sandwhiched with both rear and front mod next mod 4. 
Changes to the mass loading affects the vibration of the structure,
and thus the resonant frequency of the structure vibration.
That means the shift & elimination of the resonant frequency is a measure of the density of the structure.

Killing structural resonance will control the problem itself,
rather than to bandage it up thru sound "absorbtion",
like the existing HD800 mods of past.

Anyways,
First, we get some specifically cut pieces of DYNAMAT EXTREME!
Make sure it is "*Extreme*" version, and keep the silver on the outside.
The silver part of this material is necessary for "vibration attenuation" thru change of layer density(usage of different layers).

*pic*





The basket frame is generally a difficult area to dampen,
So here are the *specific locations* (critical) for this mod:
Don't waste your time to do this halfway, or by using another material, or another location.

First off,
At The Back of driver inside area,
apply dynamat extreme in these sections:
*pic*




*pic*





Once done, set aside and position rear grill mod2 over it, to get ready for closing with next mod...


*************


4- *Driver side damping, ring mod.*
We replace the metal ring with a same shape ring using *dynamat extreme* (!):
*pic*




NO METAL RING...
The ring was nothing more than a "washer" used to hold the driver in place.
It was an obstruction to access the area needed to dampen the souce of vibration to the structure.

This DYNAMAT ring is of an equal location and position, of the rear Dynamat location on other side, 
for driver damping on both yet opposite opposite sides of the driver.

This is the specific methodology used,  to dampen resonance, and stop the 6k ringing...

This ring is integral to, and is the missing link to the puzzle that was needed for optimal vibration reduction...

Control on BOTH sides to neutralize the structure,
NOT ONE SIDE, as done with past metal ring mods...
You cant clap your hands with one hand right?
You need two..
Same rules apply when dealing with forces (vibrations).
Doing this ring only mod is alone, without rear mod, does NOT work (like clapping with one hand),
and metal ring removal is nothing more than placibo without the DYNAMAT EXTREME on BOTH SIDES.

What should also be noted, is the angle of the damping. Physics for results.
The smaller back-side  center of dynamat "ring" shape, *combined* with the larger frontal dynamat "ring" shape, are is a position to be in a linear line to the basket angle..

This resulting positional "angle" is both the purpose, and what makes it effective to dampen the basket..
A Specific choice rather than over doing  "blindly" or excessively damping the headphone with dynamat.

*pic*





All previous mods must be done and position in place before placing these sticky rings on.

Once front is covered, you won't be able to find the screw hole!

No problem,
just shine a light from the backside, and see how the four screw holes line up exactly with the frame:

*pic* later as its on my phone.

So you wont miss any hole location when putting screw back thru dynamat...
**edit 2022:
Instead of RUBBER CUT pieces, for washers to hold driver in secured, I refined the procedure to use flat metal washers and repurposed foam from the original ring, in this later post:
https://www.head-fi.org/threads/senn-hd800-ultimate-maxx-mod.879024/post-16569836

*pic*





..


Driver section of mod compete.


This mods which increase focus, is a bit of a "double edged sword"...

Because the stock HD800 no longer has the diffused trebles to extend a bit of false "soundstage diffuse air" ..

So with increased focus, layering & separation,
comes less of the extended false diffused air type soundstaging, and replaces it with more depth and accuracy,
For a noticably more palpable  and greater experience.

This whole mod is also reversable if ever need.
Only messy, as you would have to clean up the dynamat.

I highly doubt anyone would want to reverse this mod after listening to the _*lazer pinpoint imaging and clearer textures *_though...

All mods up to this point can be used on "SDR" modded headphones.

Completing the initial mods, would be with the earpad mods, later in this thread:
https://www.head-fi.org/threads/senn-hd800-ultimate-maxx-mod.879024/post-16545288




**** **** ****



5- *The 800 "S" resonator mod:*

Edit**
Another unkown topic, is about the center hole.
Why a center hole?
Why not just cover it up?
Because it will sound closed..(!)

While true, the resonator in the 800S brings more lower spectrum, it is (in my opinion, from my research) was originally intended to be a relief of the internal air chamber pressure (where your ear is).

Placing a "resonator" there covers the excape of pressure, so it mutes low level transients, because the driver membrane is thin.

This effect is most notable in the 820, but only  with side by side comparison with the 800.

On the 800S, the effect leads to more distortion, or a "fullness" in lower spectrum, along with greater bass from less escaping air pressure...
So there was a balance to strike, and the 800S was the result. Very nice change, but not as "clean" sounding as the original.

Regardless,
This part of mod will give a very *similar* sonic character and signature of an HD800S.(!)
Use ONLY these specific Sennheiser "ear-tips"!

*pic*





Make sure the serial number is same.
No other material will do.

Cut the rounded edges off,
to necessary depth (of an SDmod), and then Insert these tips :
*pic*




Easyest part of the mod.
Install same as you would an SD mod.
Please refer to the SD thread for installation.
Here is pic with SD on left, and "S" mod on right:





Get them, fresh from *DIRECT SOURCE.*

OR these other sources, while you still can..

So if the Main source dries up, Look here also:

HERE

AND HERE

AND HERE ALSO.

Done. Main mods done.
Enjoy.


The following steps below, are additional mods not necessary.

*****************************


*Optional Mods:*


6- *INTERNAL WIRING MOD:*
Replacement of micro stock wiring CAN give you positive results, "IF" done wisely.

That means replacement with *known good sounding wire*...
*NO SILVER PLATED, OR MIX PLATED WIRE*...

Lets take a look at the super tiny size of this wire(!)
*Pic* ( update later)

OMG broken pin,
And 100 AWG! (kiddn)
It is neither OCC, nor good enough guage.
It will ALWASY present an "impedance" to your system...
And I mean that LITERALLY! !

0.1 OHM RESISTANCE MEASURED ON EACH wire, not including connectors !!!

While that amount may seem small, it does matter here.

From my testing, not only the wiring, but BOTH the wire AND the stock connectors have influence on the HD800 drivers..

Remember, we are dealing with on of the most resolving dynamic driver currently,
So everything makes a difference when you're dealing with the HD800 and why cable changes can be heard with the 800.

The easiest suggestion would be to install cable hardwired into driver and eliminate the connector...

I did this at first, but the drawback, is missing the option to upgrade to other cables,
So instead I choose the mini XLR sockets in step 7.

Seems that stock wire was thin for a reason.
Choosing here, steers the difference between sweet or dark "qualities" in the headphone.
Qualities that pertain to cable preferences.
If you ever thought wires make a difference,
At this location magnifys it.

This is one recommendation of only wire to use:
Neotech Stranded AG/GD in PE 24ga:
Neotech AG/GD-24 is a stranded, 99% UP-OCC Silver & 1% Gold chassis wire in a clear PE jacket. 

The reason for this wire, and at that gauge mentioned, is that it was the perfect size, and it preserved a similar original qualities of sparkling clarity and resolve, while keeping the main advantage that most re-wiring does, which is a more powerful low end. 

Also, the choice of solder.
I used to use normal solder.
I noticed a much better flow and work with Cardas solder.
It was superior.
But now I have switched to 
The "Mundorf MSolder SUPREME Solder Silver/Gold"
It was to match the consistency of the silver/gold wire.

I am sure there are other choices, but I will only recommend what I know works.
Better than stock wire, and better than the silver plated wire tried, and better than larger guage wire tried.


Ok ,
so now the problem lies in soldering on the connector side.

It is a fragile piece on inside soldering points, and is a sonic "choke point".

YOU MUST have the steady hands of a surgeon to complete this task,
Or you could be out of commission with a broken socket! (On wiring end).

It's like Sennheiser just put a tiny connector to show off and say,
"look at me, I can make a super slick super tiny iem guage connector!" Lol.

It really is that fragile inside...
Pic*later of broken internal pin.
Lucky I had extra stock connector.

I found the best way was to UNsolder wires from the driver post first,
Then remove the connector,
Then cut the wire close to the inside connector tips,
But leaving some wire as it is inserted microscopically and deeply inside.
Then tinning(solder) and reinsert into housing to solder the wires on top.


********************************************


7- *MINI XLR MOD:*






As stated before, the ideal solution would be to totally discard the stock connector...
It is a POS stupidly designed garbage stock connector.

The bottom line is,
those dam forsaken garbage HD800 connectors, WILL "add" to your sound.

So take out, and boldly drill away a larger hole! !
For a mini XLR connector!
The mini XLR I consider easily MORE transparent .




Ok,
So It was not an easy thing to do either,
as it had to be drilled a bigger hole,
at a slightly forward angle to fit in.

BE VERY CAREFUL,
to get that drill bit in THERE,
As it is so close to the driver soldering posts!

Pic*




This was a silver plated wire which is NOT recommend.


The end result of mini XLR socket is very slick:
Pic*





And it actually makes it better when using the hd800,
Because the cable is now very Slightly angled forward and away from you.
Plus the shiny connectors are cool.

Here is an updated guide on this mini XLR mod, with specific  tools, posted later in thread here:
https://www.head-fi.org/threads/senn-hd800-ultimate-maxx-mod.879024/post-17098858




*****
Enjoy your *Ult mod*.


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## Maxx134 (Feb 29, 2020)

After a few discussions, it is clear I must clarify on the importance of the:
*ANTI-RESONANCE MOD ( BOTH STEPS 3&4)

Edit***
From further investigation, Senheiser applied a vibration damping scheme, yet it was only partially done inside bottom of the driver.
There is a sorbothane padding.
Sorbothane works in two scenarios.
Compression, or expansion.

The metal ring is specificly used to apply a very even circular compression onto the driver for the rubber/sorbothane to work.
Unfortunately, the did not "sandwich" the driver with sorbothane on the top, so what you have is a partially dampened driver.
A thin felt was applied to the metal ring to help instead of more sorbothane.
This, to me, was a design compromise, and the reason why my usage of dynamat fully resolves this issue.

So instead of compression with sorbothane, I just use dynamat which is a sloppier alternate but most effective.

To complete the optimal design of the hd800 compression, another circular layer of sorbothane would be needed on top, and then the metal ring.
That would also necessitate the use of bolts for the additional necessary pressure of added piece.
There is a member in another forum who uses and made not the bolt size needed.

It is unknown if completing the compression method would be as effective as the dynamat.
It would be cleaner for sure.

I would have to test that idea in future.

Currently, my dynamat method does not involve additional pressure, so the original screws and grill can be retained..

Onto the dynamat method:

*I cannot stress enough* to use Dynamat Extreme *in the perscribed specific location*.
I do not suggest in any way to fill the unit up with any Dynamat in any locations.

This is not guesswork,
So I must give some theory and details now...


*Only* "Dynamat Extreme" is used, in what is essentially two circle shapes...


The shape of the driver edge to be exact,
and for a specifically good and exact reason.


No guessing and splashing dynamat all over unit, in less important areas.


One in circular mass in  front, and essentially  one behind.


The idea is to stop the vibrational source area (where driver meets structure) in a _specific way..._


In order to do so, we place an almost equal and opposing mass in front and behind the driver(!) in the *specific* locations...

Not in any locations far away, which do not have the *similar effect*.


Think of the HD800 speaker vibration as a moving car tire.

If you want to stop it (physical energy), you must have brakes, which contact on TWO opposing SIDES to push up against, as  you cant stop motion with nothing.

Same effect when you blindly load the rear with plain Dynamat,
you essentially do *nothing* to *ACTUALLY STOP* the physical vibration.

You only have one side (rear) with dynamat, boucing rear vibrations out to the front basket-frame..to thus be added.

This is like a ball (vibration) hitting a soft "wall" (one side of Dynamat) and bouncing back with a dampened (lesser but still there)force back in...to the front!

So your actually amplifying (or actually thickening with more time delayed vibrations) , by adding (deflecting/bouncing) some rear moving energy (vibrations) to the front!
A total waste of time, and not any solution.

What is needed, is vibration attenuation, not spot mass loading, and random diffusion (bouncing vibrations),
which also introduce more complex vibration patterns to the basket structure..

Think of a bell ringing and only touching the inside (rear) .
It still rings but with different ripples of sound.

That's what happens to a "rear only" half done job with regular Dynamat or other material...

It does not stop, as when pinching both sides of the bell, or  cymbal...

Or
Like, (last example) what a car brake does to it's wheel, by the caliper squeezing both sides of the rotor.


Ok,
So what is done to the front, we need to do similarly to the rear,
To achieve "vibration attenuation".

We are addressing physical vibration  damping,
in both the
"horizontal plane", and the angled-plane" of the basket...

How?
If you take notice, the rear is in a smaller circle.

So there is a "line-of-sight  "angle" between the inner and outer dynamat rings.

This important, because it is in line with the basket trajectory.


So, three things are at play:
not only is the dynamat on both sides,

but it is also on the inner and outer sides of its donut "ring radiator"

And is in an angled proportion to the angle of the basket...(!)



_Physical_ (not diaphram sonics) _Vibration_ is thus optimally attenuated in the _angle_ of the basket structure...

Why?.
Because the basket structure, is essentially  shaped like a "cone" megaphone, so it would naturally amplify or extend out vibrations from the center (including the driver)..

We want the diaphragm sound dispersion, but *NOT* the driver vibration to be transmitted to the structure,
because the structure can act similar to like a horn speaker.

So my point is, that although we are finally getting good results with other recent methods, (foam, special materials, Pads
Or even the SDR insert & my "S" insert...)

They  ALL are NOT addressing the root of the Problem.

They ALL only work to work to "absorb" the resulting sound.

Its like taking medicine for a cold to stop the symptoms, but adds its own drowsy effects(like _transient muting_), and is not the actual cure.

_*Only the Dynamat Extreme, "Anti-resonance Mod" will control the root of the Problem.*_

It "sandwiches" the driver in the "horizintal &  basket-angled planes",
to attenuate the driver initial vibrations,
which would then transmitted along the basket, in a similar way a horn speaker amplify!

This is where we get the diffused exageratted soundstage.

No other part of this mod is more important.

No other solution out there, are "Vibration control".

No vibration metholody before,
has taken into consideration my ideas of damping physical vibration,
Both on the horizontal and angled planes..

None have addressed this area in this way before.
You can't just slap some Dynamat on the unit, and expect results,
Or say there are none.


The lack of it being a "driver problem", was known elswhere for a long time.
The driver was not the cause of the ringing.
Once this was known,  others tried structure modification with mixed results.

The real issue here, is that my mod proves that the initial vibration from the driver edge,
gets transformed and skewed (resonance) and added into the the physical sound dispersion characteristics (which are known in horn loaded speaker designs because of cone shape basket).

So although this shape is good for dispertion of the soundfield, this specific structure is also transmitting the driver vibrations into the soundfield,  making what is observed as an "added" characteristic of an exaggerated and "diffused"  soundfield presence.

Controlling the "initial" vibrations before they get transmitted to the structure is the key .

It should be noted,
that although a conical shape structure is designed to distribute the sound field nicely,
It _does not_ have to add/transmit a diffuse the sound field to the sound, as it is doing.

Remember,
This mod was replicated on two HD800 already, tested and unbeaten over a year already.
So It is proven to be replicated and solid.


----------



## omniweltall

Pse carry on, mate. We're listening....


----------



## Maxx134 (May 7, 2018)

omniweltall said:


> Pse carry on, mate. We're listening....


ok I updated second reserved post.
Third reserved post will have the actual mod.
It will have lots of pictures.
It will be uploaded tomorrow regretfully as I must leave work soon no time.
It will be worth the wait.
This mod was replicated on two HD800 already.
So It is proven to be replicated


----------



## johnjen

I look forward to seeing what you have come up with.

JJ


----------



## Maxx134

johnjen said:


> I look forward to seeing what you have come up with.
> 
> JJ


DONE..
Check posts..


----------



## Maxx134 (May 8, 2018)

I will be updating thread with comparison maeasurements done on same measurement rig against another moded HD800..
It happens to be a very excellent mod which is superior to most.
It is a hybrid mod, a HD800 with SDR MOD and my SUBBASS MOD and have HARDWIRE MOD with Stephan Audio Endrorphen cable...
That guy was on the right path when he mentioned and talked about vibration.

Suffice to say that is a very, very excellent moded HD800...
THIS WILL be an ultimate test and showdown, for my Ultimate Mod.
IT should prove beyond shadow of doubt whether this mod is truley worthy.

The key, is using same measurement rig, on a known proven worthy Moded HD800, to have valid data.
To be honest, using a stock HD800 would have been way too easy...
I must test against the best HD800 mods, in order to prove superiority...

Edit:

Update.
I have completed the test measurements for both headphones.

The tests were justified to show mine better but are long winded,
So I will post that later.

But I was suprised they closer in one specific area.

While the diffuse stage was bad and measurable on the other unit,
The 6k ringing actually was better than expected which I will post.
I feel it is due to the SDR mod.

So I will still need to measure a stock HD800, to see how far the ringing lasts when measured with my coupler..

From my testing the diffuse soundfied is not specific to the 6khz ringing or resonance.
 It encompasses all the vibrations from the driver.


----------



## Maxx134

I have updated second post on the importance of the "Anti-resonance" damping mod.

It must be applied specifically or you can be wasting your time.
So some theory and  explanations are given.

That part is the most important for achieving focused, lazer pinpoint accuracy and clarity.
It is what makes other HD800 or HD800 sound blurry and dirty in comparison.

If you think your HD800 already sounds clean, and cant possibly get more resolving...

You will be very surprised and awed,
 by jaw-dropping focus and clarity.
Actually, if possible, just Imagine the same sound, minus the diffused soundfield.


----------



## omniweltall

Maxx134 said:


> I have updated second post on the importance of the "Anti-resonance" damping mod.
> 
> It must be applied specifically or you can be wasting your time.
> So some theory and  explanations are given.
> ...


This is the most extensive mod I've ever seen. You are really sumthin', man.


----------



## Thenewguy007

Can you elaborate on the rubber tape part? Any specific brand you bought?

Also why does it look wavy in your pictures?


----------



## Maxx134 (May 9, 2018)

Thenewguy007 said:


> Can you elaborate on the rubber tape part? Any specific brand you bought?
> 
> Also why does it look wavy in your pictures?


It is a rubber tape that had NO adhesive.
Rubber tape is easily found in the hardware store next to the electrical tape.
It is made to be used by electricians, over electrical tape to create a water tight seal for wiring connections that will get wet.

Anyways, it is a tape that only sticks to itself, which is what we want.
The reason you see a bit of it wavy, is because it had to bend inside.
No big deal.

The tape was folded in two, to  match the with of interior pad flap.
It tucked nicely inside and gives a gentle lift to the pads.

It prevents the older pads collapse and keeps the "new pad" feel and  lift, for better soundStage as well.

Once settled they feel normal.
It gives a more solid coupling to face so less  bass impact is lost out the cloth pads.
I updated a bit info in post.


----------



## superfluke

Don't think I'm brave enough to try this but it looks really good. Great work.

out of curiosity, have you tested those ear-tips vs the SD resonator? without the other mods would you rather the eartips or SD?


----------



## Maxx134 (May 10, 2018)

superfluke said:


> Don't think I'm brave enough to try this but it looks really good. Great work.
> 
> out of curiosity, have you tested those ear-tips vs the SD resonator? without the other mods would you rather the eartips or SD?


Yes they both perform same function.

The SDR gives the HD800 sound with bit  less, balanced trebles,

And the "S" mod gives you closest to 800S signature.

You can do those and be happy with reduced ringing.

The Dynamat mods are for elimination of the diffused aspect in the soundstage, giving you more transients focus.

So yeah the inserts are easiest to do.
Also the subbass mod is easy.


----------



## omniweltall

Maxx134 said:


> Yes they both perform same function.
> 
> The SDR gives the HD800 sound with bit  less, balanced trebles,
> 
> ...


Which is better...the "S" or the SDR?


----------



## Maxx134

omniweltall said:


> Which is better...the "S" or the SDR?


Good question.
I am going to say I prefer "S", because they both do the same job, but the SDR is for a "flatter" response,
While the "S" is for an HD800S like response, where you notice both more low end, and more sparkle.

Both negate the ringing, but neither address the "diffuse soundstage" aspect of the HD800 series.
That is what my other mods here cover.

It really up to preference, and is so cheap you should try both and have both.


----------



## Maxx134

I will update results in near future with another choice of pads, and another choice of internal wiring..


----------



## Maxx134

I updated end of first post with more test results from another HD800 which is SD moded and hardwired with an expensive cable.


----------



## Thenewguy007

Maxx134 said:


> I updated end of first post with more test results from another HD800 which is SD moded and hardwired with an* expensive cable*.



What's the cable?


----------



## Maxx134 (Oct 13, 2018)

Some StephanAudio cable.
Its not my HD800 but looks like a well done job.

Personally, I really like this cable for the HD800:


Was comparing it to a Draug2 cable & it has more air and liveliness.
Both are OCC copper.

My own cable is silver so I have to compare this next time to my silver.


----------



## johnjen

I too really like the SAA cable I use on my A set of 800's.
He did a really good job of designing a suitable cable for them.

JJ


----------



## Maxx134

johnjen said:


> I too really like the SAA cable I use on my A set of 800's.
> He did a really good job of designing a suitable cable for them.
> 
> JJ


This is true.
The HD800 has a sweet signature with that cable.
That's the one thing I have to agree because you can go thru many cables even silver dragon not better than that SAA cable.


----------



## Maxx134

Just an update:

Performing some new experimental testing, is showing promise to further boost the HD800 performance.

Cannot specify yet untill I verify my initial observations with measurements.


----------



## Maxx134 (Oct 27, 2018)

Internal wire upgrade completed and updated in mod post.

New Pad update using best Dekoni pad choice coming next.

Dekoni pad modding secret to make Dekoni pad optimal, coming next.


----------



## Maxx134

updated importance of the "Clarity C80" measurement, showing this mod has more than double the clarity measurement of a stock or SDR moded HD800..


----------



## Dukei

Can I only do the bass mod for increased bass or do I have to to do all the other mods to get the "full" bass sound?


----------



## Maxx134

For affecting Bass & lower range, just try the pads tape insert, and more importantly, use the center mod using Sennheiser foam I used in place of SDR mod, which give it a similar  "S" version tonality.


----------



## Maxx134 (Jan 21, 2020)

The Dekoni ferenstrated lambskin pads also helps  address the the treble region peak that the SDR & my Senn "S"mod foam addresses.

The drawback is slightly less bass.

I believe this is a design choice that Dekoni made on that pad base.
The plastic base does not have the "membrane" on bottom that stock pads have to retain bass..

Yet the other Dekoni pad choices were not as "open" sounding.
This is very important to me.

My approach is not using  anything that is less open sounding than stock.

That is why in this thread, there is no selection or mention of ANYTHING that would reduce soundstage.

So no use of internal rug liners, or creatology foams, or really anything that would decrease the effective *internal volume.*

This is also why I am switching to Dekoni ferenstrated lambskin pads, regardless of bass issues...

Stock pads reduce internal volume as they are already shallow, and get more shallow as they get old...

It is my opinion that the HD800 driver design benifits from more internal volume.

My studying of it leads me to believe that the larger volume better propagates the soundfield wave pattern, like what a horn speaker does.


 
Also any room speaker does similar, by projecting outward the image, and as it disperse, it fills the room getting larger..

I feel the planars & electrostatics have the advantage of a way more flat sound wave pattern to travel to the ear, but the wave is already "large", so the ear is already immersed in a large sound wave, and the ear's localization cues detect a large image.

So, my opinion is that the HD800 basket frame helps the driver simulate a larger spaced image.


----------



## renugaid

Any updates on the dekoni pads experiment?


----------



## Maxx134

Dukei said:


> Can I only do the bass mod for increased bass or do I have to to do all the other mods to get the "full" bass sound?


You should just try the insert .
It's a cheap easy placement of using the specific  Senheiser tips mentioned.


----------



## Maxx134 (Sep 23, 2021)

I am currently working on a different mod to alter the HD8000 FR:


Simultaneously increasing lower bass while also increasing clarity in middle range:

HD800SDR:


My New mod:


I do not compare to stock HD800 as it would not be fair, as I expect most owners to use the SDR by now.

Bass levels should be up about 8db from stock and at least 3db from an HD800S, although I haven't been able to measure one yet.

So all this is ongoing while I see if I can tailor the FR some more to reduce the 4.5k dip.
This is before the dip correction.
Here is a CSD:


Cheers.
Edit:
10khz & up would be considered "air" and shows I have not dampened or muted the upper range with materials with would kill soundstage.
Instead I have a larger & deeper image than before.

It's progress but not complete for me untill I address FR more.

Edit*:
Forgot to mention the whole CSD primary image is way under the 1ms line & actually all is way before even half the first 1ms box, which only  450hz point shows at that point.
So initial image is clean.


----------



## Maxx134 (Jan 13, 2019)

Ok I been further experimenting with "transient response" and tonality.

From my FR grapth, you see my aim was for the more involving sig of both the Susvara and Abyss in the lower spectrum.

That combined with what I have been learning about how transient response pertains to sonic impression.

So I changed the HD800 transient response for aa transient response to be like what I researched, which  stated that for the step response to be more like a speaker, it must drop below zero for a sufficient time to produce a net output of zero over time.

This involved and affected the imaging, "agressiveness", and dimensionality.
These parameters were then optimally changed.

So I ended up making the sound more open &  holographic while having more of a perspective of "being there", as opposed to "being presented" an image.
This, with the tonality change adds to a more "live" experience.

"Clarity" graph was substantially increased in lower spectrum, but can also be a reflection of the bass increase.
Bass sensitivity incrimented another 2-3db on top of last FR grapth.
Total bass level is now substantial enough.

Treble has also been altered, not for any 6k issue as that has been addressed/corrected and is totally non-existent even in distortion measurements.
This done in a new way, unlike "center-driver" mods.
So treble progress made and is being tuned for non-sibilance, WITH extension.

Edit** Although visually this is an HD800,

it is no longer an HD800 sonically.
It is more like "stax009"(livelyness) mates "Susvara"(openness) to me.
Makes normal HD800 versions sound flat ("2D") and less real.
Will post measurements soon.
 Not done yet.
This will be next project.
 "HD800X" project.


----------



## Thenewguy007 (Jan 1, 2019)

Ever think of trying these new earpads?

Leather, but not as thick as the Dekoni, so they shouldn't mess with the signature too much.
https://www.amazon.com/misodiko-Upg...=UTF8&qid=1543095904&sr=8-7&keywords=misodiko
https://www.amazon.com/dp/B07G4FKXKG/ref=psdc_13880181_t3_B07GSWPXV1


----------



## Maxx134 (Jan 1, 2019)

Thenewguy007 said:


> Ever think of trying these new earpads?
> 
> Leather, but not as thick as the Dekoni, so they shouldn't mess with the signature too much.
> https://www.amazon.com/misodiko-Upg...=UTF8&qid=1543095904&sr=8-7&keywords=misodiko
> https://www.amazon.com/dp/B07G4FKXKG/ref=psdc_13880181_t3_B07GSWPXV1


I have seen three or four iterations of replacement pads on Amazon.
Every single one of them will changed sound somewhat.
Even worn shallow pads make HD800 sound different.
Cheaper price is nice.
I personally prefer Dekoni ferenstrated pads.
The plastic under the cheapo pads are there for bass leakage prevention.
Dekoni needed to implement this.
It helps but not much.

I have edit my past post a bit.
I am on my phone so easy to typo and skip things.


----------



## Maxx134

Thenewguy007 said:


> Ever think of trying these new earpads?
> 
> Leather, but not as thick as the Dekoni, so they shouldn't mess with the signature too much.
> https://www.amazon.com/misodiko-Upg...=UTF8&qid=1543095904&sr=8-7&keywords=misodiko
> https://www.amazon.com/dp/B07G4FKXKG/ref=psdc_13880181_t3_B07GSWPXV1


According to my experience in generall, those specific pads will probably give a bit tighter bass but more closed in & bit darker sound.


----------



## omniweltall

Maxx134 said:


> According to my experience in generall, those specific pads will probably give a bit tighter bass but more closed in & bit darker sound.


That is my impressuon as well. Im using dekonk fenestrated as well. My worry is more on details and resolution.


----------



## Maxx134 (Sep 23, 2021)

update on the HD800"M" project .
cleaned up the lower spectrum .

more clarity .
this becoming a true  all genre headphone now.


getting  closer .
check bass extension .


----------



## omniweltall

Maxx134 said:


> update on the HD800X project .
> cleaned up the lower spectrum .
> 
> more clarity .
> ...


Looking good, Max!


----------



## Maxx134 (Jan 21, 2020)

Maxx134 said:


> update on the HD800X project .
> cleaned up the lower spectrum .
> 
> more clarity .
> ...


Update here was I reduced the dip of the new signature,  and made some FR changes, but I want to tune the image "distance"  a bit more and then thinking to present it to Senheiser in coming months, as intelectual info, since it is a modification that can be done by them.
 I haven't done anything more yet, as I was testing the reliability of the mod.
Next step is to squeeze out more low end extension.




Here are more measurements:





CSD, 40db down in a 2ms window(!).


----------



## audiophiliac69 (Jan 16, 2020)

For anyone with a Senheiser HD800, this is THE tread to follow. And it is not IMHO, if you think I am wrong point me to a more credible thread.
I want to thank you for all your work on the HD800 and patience with the nay sayers.
Looking forward to HD800X project. Keep up the excellent work. Color me impressed!


----------



## Maxx134

Thenewguy007 said:


> ver think of trying these new earpads?
> 
> Leather, but not as thick as the Dekoni, so they shouldn't mess with the signature too much.



Check this post

This implys that distance of the driver was intended in the design.

This is why the Dekoni pad is preferable to me.

Others may prefer stock size pads, as it also gives a bit more closer and darker image.


----------



## Maxx134 (Feb 29, 2020)

Here is a another mod help for those with Dekoni pads, and are experiencing less bass..

Buy THESE Gesongzhe Earpads for the hd800, to extract (by cutting) the silicone membrane (needed for bass seal)...

It is a softer membrane than the stock pads, which use soft plastic.

Both work, but the silicone membrane is better.

Carefully cut out the silicone membrane...


It says plastic, but to me it feels more like silicone.
THIS is what preserves the bass!

install it between the dekoni pads and the headphone.

Result is improved bass!
Dekoni chose to not implement this, as a trade off for having it's "twist off" removal feature..

This is implemented in my latest version to get more sub-bass extension.


----------



## Maxx134 (Sep 23, 2021)

I will be at canjam with my latest  HD800M if anyone wants to hear.



This is my latest and totally new mod of mine for the HD800, with a deeper, larger, more neutral s& non-diffused sound, without any center insert, or any internal damping of cage at all, for maximum soundstage.


----------



## Thenewguy007

Nice paint job, where did you go to get it?


----------



## Maxx134

That was a "colorware" special edition.


----------



## Maxx134 (Sep 4, 2022)

Update:

I will be renaming the latest iteration of the mod, to get away from the rest.

New name will be HD800M, and HD800SM, 
 because it will be maxxed out.

It is Literally the most that can be done and squeezed out of this design, without Actually changing the headphones..

Due to invasiveness of the next & latest iteration of the 800"M" mod, possible corruption of the driver can occur if anyone tries without my methodology, as did during the initial moding of my Carbon edition:


The realization that I needed a new methodology with different tools that not exist. 
As if 2022 refinement made had dropped the high failure rate of over 80% to 50% during the modification process.
Therefore I have to add in cost of one driver as expense overhead. 
Once complete, process is permanent and stable.

Visual measurements below:

Remember this is all done in non traditional way.
No stupid felts or foam cut outs placed inside the metal cup.
No raping of the driver front screen to voilate it's center hole to imitate Senheiser with the 800S.
No placement of rug liners to kill soundstage.

No Resonance.
No ringing.
No diffuse sound.
No small or even normal soundstage.
No dead sounds of rug liners.
No sucked out sounds.
No tame sound of SD type inserts.
No thickening of the sound like 800S & 820.
No anemic bass sound.
What is sounds like is very close to a Susvara in depth. A deeper, larger, much more neutral & non-diffused sound.

Edit**
Final tuning cleaned up trebles & lowered trebles a touch.
FR & Dist:



Notice no dist peaks from 1k all way up.
Had fishtank in background noise.

CSD:



Looking from 1khz up all is less than .5ms

CSD is 30db down & extended to 200hz to see more.

The lack of slices immediately after initial sound shows how fast, clean & clear it is, compared to the density of slices in left.


----------



## Maxx134 (Sep 4, 2022)

I updated my findings on my dynamat usage:

Basically, it confirms my reasoning for damping.

It turns out that the HD800 was using a type of rubber under the driver, which *required the usage of the metal ring(!)*_ For the necessary even compression to work_*.
sorbothane *_(in this setup)_* works by compression.*

This confirms my idea of the necessity to dampen the driver.
In my case, I chose the dynamat route, instead of the sorbothane route.
Those are the two choices for vibration control.


----------



## Maxx134

I also mentioned the updated upgrade choice of  using Dekoni ferenstrated lambskin pads, in combination with using the Specific silicone membrane that only the non-senheiser pads (mentioned earlier in thread) have.

That will optimize both wave propagation  (soundstage ) while keeping bass seal (with the silicone membrane).


----------



## Maxx134 (Feb 29, 2020)

I posted an update explanation about the resonator mod in first page.

With both the driver damping, and resonator mod explanation, it looks like all the Hd800 secrets are now revealed on first page.


----------



## MadMan007 (Oct 8, 2020)

Hello, I came across this thread searching for HD800 mods, I have unmodded HD800 currently. Of course, I know about and was planning on the SDR mod at least. You mention here an alternative to the SDR mod materials...

"So there was a balance to strike, and the 800S was the result. Very nice change, but not as "clean" sounding as the original.

Regardless,
This part of mod will give a very *similar* sonic character and signature of an HD800S.(!)
Use ONLY these specific Sennheiser "ear-tips"!"

1) Is this an alternative material to perform the SDR mod, even without your other mods? Will it fix the 6kHz etc treble peaks and overall do the same as the SDR mod?

2) The 800S has 2nd harmonic distortion in the bass compared to the 800. As far as I know, the SDR mod does not add this distortion. Are you saying these foam eartips *alone* add 2nd order distortion like the 800S? You said bass distortion measurements were not accurate due to noise floor, so I don't want to misinterpret the bass region of distortion graphs.


----------



## Maxx134 (Oct 13, 2020)

MadMan007 said:


> Hello, I came across this thread searching for HD800 mods, I have unmodded HD800 currently. Of course, I know about and was planning on the SDR mod at least. You mention here an alternative to the SDR mod materials...
> 
> "So there was a balance to strike, and the 800S was the result. Very nice change, but not as "clean" sounding as the original.
> 
> ...


Sorry late response I so busy on other projects.
Yes to all above.
All should try the foam I suggested first before any other modifications.

You only have to cut the round top as it is a bit longer than the depth of the hole.
Not even have to be exact as it compress inside a bit.
Consider it a bit more enjoyable vibrant colored version (keeping more bass & trebles), while the SDR is a more tame neutral version.
Remember that any other Sennheiser tips will not work. 
Must be the specific tips I posted.

Regardless I will be progressing on the mod soon as I develop new tools to achieve a high success rate in my next mod which you see I posted above (800X mod).
Cheers


----------



## spikeyw

Maxx134 said:


> First off,
> At The Back of driver inside area,
> apply dynamat extreme in these sections:
> *pic*
> ...



Many thanks for posting this comprehensive mod and the enormous amount of time you must've spent on this.

I've just got one query regarding the step 3 above, I'm confused how to apply the dynmat shown in the above 2 photos. Do you apply dynamat in a full circle pattern or half moon.


----------



## Maxx134

spikeyw said:


> Many thanks for posting this comprehensive mod and the enormous amount of time you must've spent on this.
> 
> I've just got one query regarding the step 3 above, I'm confused how to apply the dynmat shown in the above 2 photos. Do you apply dynamat in a full circle pattern or half moon.


They are cut pieces to go around in a circle. Pic looks half completed in one.


----------



## spikeyw

Maxx134 said:


> They are cut pieces to go around in a circle. Pic looks half completed in one.



That's perfect. Thanks for answering my query so quickly. I'm going to continue modding my HD800.


----------



## Maxx134 (Mar 9, 2021)

Hello I'm updating with recent initial preliminary tests using 1mm silicone ring:



Observation of the reduction of small consistent variations after 200u, verify that the "compression method" could be tried as a viable alternative to dynamat method, on the metal ring area.

In other words, it looks very promising to use lighter cleaner sorbothane sandwich (both under and on top) of the driver, in place of dynamat.

Next round of tests will be using actual sorbothane "ring" of 2.5mm thickness chosen at 30 durometer.


----------



## Maxx134 (May 14, 2021)

I updated initial first page post with an
initial comparison to an SDR mod, to show the difference of more upper FR above 10khz (air), and more lower spectrum:




So this is to point out that my mod is more like an 800S, while the SDR mainly focused on the 6k ring & peaks.

For those that have good ears, you will be able to tell the difference in upper FR that comes across as "air" in the trebles.
Stock also has the "air" but any other mod than this, will "close in" the soundstage and air, as seen in this comparison.


----------



## Maxx134 (Sep 23, 2021)

Added more actual data of improvement over stock HD800:

Ripple at 2.5k,  47db down of stock:


Cleaned up with mod:


This is proof of the ELIMINATION of resonances from my damping methodology.


----------



## Bryan E

Hey I'm currently doing your mods, tho due to being in a far away country with no way of purchasing a dynamat Xtreme, I decided to cut a few corners hahaha, I used a damper with similar thickness with the dynamat, and for the shelf liner I couldn't find the ones exactly like yours so I find a similar with a slightly different pattern... 

Tbh They sound crazy fantastic, tho I want to ask if putting the dynamat ring on top of the metal ring would make a huge difference vs just replacing the metal ring? Because I tried just covering the metal part of the ring with dynamat and they, seem to perform very well...


----------



## Maxx134 (Jun 23, 2021)

Bryan E said:


> Because I tried just covering the metal part of the ring with dynamat and they, seem to perform very well...


The metal has a foam layer under it, which hampers the dynamat effect of solidifying the driver to the basket frame.

IMO, Sennheiser made a mistake using foam, instead of the sobothane ring they use under the driver. I personally believe this was not as designed and a change because of cost and replacement would be easier with the foam on that metal ring, instead of sorbothane.

So if you don't want to use the dynamat as a replacement, you could try cut out a super thin sorbothane or silicone layer to put under the metal ring, and flip that metal ring upside down for more solid bond.


----------



## Bryan E

Maxx134 said:


> The metal has a foam layer under it, which hampers the dynamat effect of solidifying the driver to the basket frame.
> 
> IMO, Sennheiser made a mistake using foam, instead of the sobothane ring they use under the driver. I personally believe this was not as designed and a change because of cost and replacement would be easier with the foam on that metal ring, instead of sorbothane.
> 
> So if you don't want to use the dynamat as a replacement, you could try cut out a super thin sorbothane or silicone layer to put under the metal ring, and flip that metal ring upside down for more solid bond.


I C thank U for your info ... Is there a way to mechanically increase 1-2khz region because that is IMO the only weakness of HD800 that hasn't been resolved by any mod as of now hahaha


----------



## Bryan E

How thin should the silicone layer be? About 1mm?? And should the dynamat behind the driver replaced with silicone too to match the one in front? And how thick should the silicone behind the driver be?


----------



## Maxx134

Bryan E said:


> I C thank U for your info ... Is there a way to mechanically increase 1-2khz region because that is IMO the only weakness of HD800 that hasn't been resolved by any mod as of now hahaha


Try the specific Sennheiser foam tips (to place in center driver) I recommended in beginning of thread.
It is probably the first mod anyone should try.



Bryan E said:


> How thin should the silicone layer be? About 1mm?? And should the dynamat behind the driver replaced with silicone too to match the one in front? And how thick should the silicone behind the driver be?


After my own trials, I actually don't recommend any silicone because it requires compression that the screws cannot give.
You would actually have to do a nut an bolt all way thru and end up having to discard the whole plastic rear and grill.

Its not worth the effort to try, plus it will not have the advantage of increased mass, which is what is needed to properly eliminate resonances, and results in the increased presicion of soundstage. (No artificial soundstage haze).


----------



## Peter19500 (Sep 5, 2021)

Sorry


----------



## Peter19500

Please specify more precisely these materials:

*"BASS Pressure/COUPLING SEAL" MOD*.
specific material to slow down the bass pressure from escaping pads
sub-bass seal and Impact preservation, inserted to the inside of ear pads.

*2-rear grill *Anti-reflection mod*,
This is accomplished by using specific deflective material by grill.
Yes those mesh metal screens in rear affect sound,
but you don't have to take them off (idiot approach).
No grill removal is necessary, as other mods, and this solves listener fatique from rear reflections.

Ideally it would be to link to store pages. Thanks for your work!


----------



## Maxx134 (Sep 5, 2021)

Peter19500 said:


> Please specify more precisely these materials



Hello, here is pics of the exact material I used. I am pretty sure you can get similar type:


🧐
Another pic for size comparison next to other items (cloth tape & screwdriver).



Also,
I do not use the rubber tape or the stock pads anymore for bass.

I only use and recommend the Dekoni elite ferenstrated sheepskin pads:



And to gain lost bass, I use the silicone from normal velour stock or replacement pads.

I cut them out to place in between the unit & pads(plastic area), when I place the new Dekoni pads on.


Good luck!


----------



## Peter19500

Maxx134 said:


> Dobrý deň, tu sú obrázky presného materiálu, ktorý som použil. Som si celkom istý, že môžete získať podobný typ:
> 
> 🧐
> Ďalší obrázok na porovnanie veľkosti vedľa iných položiek (látková páska a skrutkovač).
> ...


Ok super. Thank you very much for your quick reply. I still have the original pads in perfect condition. Should I adjust them for better bass?


----------



## Maxx134 (Sep 5, 2021)

For using stock pads, the easiest thing to try, is something very flexible and easy to fit inside the pad perimeter.
So would try some silicone tubing inside:


They key is the material being very soft and which can bend easily inside to make the turns. That's why silicone is an good choice.

I will try this tomorrow.


----------



## Peter19500

https://www.ahifi.sk/antivibracny-material-comfortmat-dark-d2.html
I have this at home.  Can I use it?  I also bought a silicone hose.


----------



## Peter19500

Is the hose enough, or is it necessary to replace the original hard plastic with a soft one?
https://www.amazon.com/dp/B07T64X8X2/ref=cm_sw_r_other_apa_i_ZTPwEbNFJ3BPW?tag=headfi-20

Thank you very much for the information.


----------



## Maxx134

Peter19500 said:


> https://www.ahifi.sk/antivibracny-material-comfortmat-dark-d2.html
> I have this at home.  Can I use it?  I also bought a silicone hose.


Interesting material to try.
Can't hurt to try.



Peter19500 said:


> Is the hose enough, or is it necessary to replace the original hard plastic with a soft one?
> https://www.amazon.com/dp/B07T64X8X2/ref=cm_sw_r_other_apa_i_ZTPwEbNFJ3BPW?tag=headfi-20
> 
> Thank you very much for the information.



That's good to try as is.

I have not tried it yet since i am not  using those pads.
But that is the correct intention an placement.


----------



## Peter19500

Does this need to be glued together? If so, with which glue?


----------



## Maxx134

Peter19500 said:


> Does this need to be glued together? If so, with which glue?


No glue at all. Just lay inside and close over driver.


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## Peter19500 (Sep 18, 2021)

I would like to thank Maxx134 for his willingness and advice.  Here are some photos from my HD800 edit.  Tin for soldering served as a pedestal for me at work.  Metal ring as a template when cutting.
I will still be doing the 800 "S" resonator mod. I ordered.


----------



## Maxx134 (Sep 5, 2022)

I have refined some frontal elements . I decided to use metal washers on the screw,



for better pressure displacement, and zero absorbing properties.



Then the black foam from the original(replaced) metal ring,  is repurposed to be used on top of the dynamat ring.

...

So you have original surface properties, and nothing else. 

This is my HD800SM mod. It has nothing else applied in this whole ear chamber.
NOTHING ELSE BELONGS HERE!
No material inserts or rug liners, which destroy soundstage.

Remember I consider tonality alterations both a compromise, and kindergarten work with no real performance correction or gains. Just masking the problems with "bandaid" solutions...


----------



## Bryan E

Maxx134 said:


> As you may or may not know, I am the only person who claims to have corrected *ALL the HD800 faults*.
> Solved everything. No one else has made this claim.
> 
> So now, I'm going to say publically, that I am _*very disappointed*_ in both Sennheiser, and Drop, and their tunning helpers from "$B@£"...
> ...


Tis a Shame man... Tho Seeing that 8XX Utter crap measurements as a result of trying to fix things without any knowledge of doing it is hilarious... Not only you I think a couple of other reviewers and modders such like DMS also tried to reach out to them about it but got Zero response...


----------



## Maxx134 (Sep 19, 2021)

Yes, everything done to the HD800, 800S, 820,8xx.. custom mods from websites or companies... 
Everything so far, has been (to me) a band-aid solution.

None of it is an actual correction or performance change. All has been muting and creating tonality change. Hiding the problems thru Frequency response.

To me, Frequency Response changes are Band-Aid solutions. My solution is an actuall change in performance, not just frequency response.
_*An actual change..*_
What has been shown so far in this thread, is only the foundation of what I have accomplished.

I'm going to make one for review.


----------



## coinmaster (Sep 20, 2021)

Maxx134 said:


> As you may or may not know, I am the only person who claims to have corrected *ALL the HD800 faults*.
> Solved everything. No one else has made this claim.
> 
> So now, I'm going to say publically, that I am _*very disappointed*_ in both Sennheiser, and Drop, and their tunning helpers from "$B@£"...
> ...


The problem is prevalent throughout the entire audio industry. There is a disguisting and inexcusable level of lack of real innovation and lack of interest in real innovation. Pride, ego, greed, hype, and laziness rule, instead of actual progress.
This is part of the reason I can almost casually make amps and headphones that make everything on the existing market sound and measure like a toy in comparison.
This problem doesn't extend to just the audio industry either. It is prevalent in pretty much all industries to some degree, but the audio industry has it particularly bad.
If I had enough money to convert prototypes into products I'd already be rich.
I'll do what I can do help you sell your mod if you need, you've done a lot for me over the years.


----------



## Maxx134 (Sep 11, 2022)

Updates coming


----------



## Peter19500

I keep my fingers crossed for you and I am very curious about your work and research.


----------



## Maxx134

As stated, those in NYC who whish to hear my unit, just PM me. I can Host in my house. Bring your source or whatever.


----------



## Maxx134

Peter19500 said:


> I keep my fingers crossed for you and I am very curious about your work and research.



I still use the damping from this thread.
This thread has the foundation of my work.


----------



## Maxx134

I will be renaming the latest iteration of the mod, to get away from the rest.

New name will be HD800M,
because it will be maxxed out.

Literally the most that can be done and squeezed out of this design, without Actually changing the headphones


----------



## Maxx134 (Sep 11, 2022)

Time to make some technical observations.

This is a normal HD800S with basket/metal mesh frame:


Nice.

Now, let's observe the "damping solution", that the 8XX implement:

Half covered mesh...
It does appear "applied" on.
By doing anything in this mesh area, you automatically will kill some of the soundstage.
Instead of dampening resonances in the driver seating area, like in this thread shows, the basket frame is dampened instead.
This is an Incomplete solution wich would inevitably have sonic change as well.


Now let's look at the driver.
Normal rear:

Nice normal holes.

Altered:


Here, we see closed off holes with material. This is how they made the scoop in the 1-3k area. Not a dip, but a scoop similar to the fostex th900.

This progression from the HD800S to this congested 8XX driver, will inevitably reduce micro-dynamics.
Also, this model therefore, cannot be changed or corrected.

Why am I the only one to tell you this. No other place to read this?
Where are the "modders" that supposedly know what there doing?
What are the reviews?

This unit will divide reviewers into two sides. The good reviewers will tell you the truth, that it is a gimped unit.

The bad reviewers (or those that shouldn't be reviewers) will tell you its fine and ok and manageable with EQ, and still good.


I am the one saying that the actual driver is "gimped". Gimped from the factory for nice THD figures.  More like a compromise, to place it as a teir below the 800S.

This is taking the HD800 series another step downward.
Although it will also change and mute some distortion.
I would have to test.

With this unit, they did what a novice modder would do, to falsely improve distortion in a driver...
To over-dampen, at the demise of both the sound and the micro-dynamics. Looks like they felt this was an acceptable/tasteful amount of compromise, for this version.
This cannot be corrected.

So I cannot, in good conscience, recommend the 8XX unit, unless user wants altered sound at compromise of other areas. 

This is *NOT* bashing. These are _*my*_ _honest* Technical observations*_...


----------



## Peter19500

I often use closed Meze99 Classics headphones when I don't want to disturb my wife.


----------



## Bryan E

Do you also make mods for the HE6? They have a resonance peak at 9khz and Ive been trying to fix them without changing the signature without nay success...


----------



## Maxx134

Bryan E said:


> Do you also make mods for the HE6? They have a resonance peak at 9khz and Ive been trying to fix them without changing the signature without nay success...


If you tried all (grill, pads, damping materials) I would lastly try replacing the material used in seating the driver to the frame.
Looks like some felt gasket ring type .


----------



## Peter19500

So today I mounted the earpads foam.


----------



## Maxx134

Peter19500 said:


> So today I mounted the earpads foam.


You have a high skill level as most of these materials are not easy to cut exact.
Same with the damping ring around the driver that was very exact cut. 👍


----------



## Maxx134

Maxx134 said:


> I will be renaming the latest iteration of the mod, to get away from the rest.
> 
> New name will be HD800M,
> because it will be maxxed out.
> ...


Started work on an hd800 unit.
Also doing some testing on an 800S driver unit to see wich driver is most optimal..


----------



## Peter19500

Thank you for the compliment. I try to do quality work. I look forward to more tutorials on improving the HD800. I no longer use the equalizer after these adjustments. I use balance output from Sony WM1Z.


----------



## Maxx134

Peter19500 said:


> Thank you for the compliment. I try to do quality work. I look forward to more tutorials on improving the HD800. I no longer use the equalizer after these adjustments. I use balance output from Sony WM1Z.


You should compare your unit to an 800S 👍


Also, working on next hd800,
I got a little carried away with my test unit mod,  and decided to strip all stock the paint right off(!), for a custom paint job.... 🙂


----------



## Peter19500

I can't compare HD800S.


----------



## Peter19500

_There is no one around me._


----------



## Maxx134 (Apr 18, 2022)

Here is my latest My HD800Maxx mod (in blue).
*TRUE BASS INCREASE*...
Notice where the 20hz db point is, in reference to the 1khz line... _Same amplitude level_*, not 5db down, *_*as in*_ _*all other "Sennheiser" iterations (*_also at least 3db higher than "Drop" HD8XX iteration).




Count the DBs & extension... *A full 10hz frequency extension*....
Normalized at the 1khz reference point, _*where it should be*_. 👍
My measurements also have no smoothing, to hide any imperfections, which most fancier graphs do.

So levels of _10hz and lower, _are now audible, without any form of artificial EQ.

Also:
Having _*the flattest *_and _*most*_ _*extended trebles*_, (past 23khz, and extending to 5khz further than the renowned "SDR" mod), translates to a more realistic and critical headphone.

Extension goes hand-in-hand, with speed.
All other graphs have to go *at least* 25-30db down, to achieve similar extension! As an example, the HD8XX barely makes it to 18khz at 25db down.

These extended parameters (on both extremes) _*serve as proofs*_ to a True driver performance *increase*...

Sonic Image Depth & size is also easily extended beyond current Sennheiser iterations, and even the current mods done here.
Getting closer to publically offering.
Currently making the demo unit.

EDIT** Picture above not updated **
Further improvements made. Flatter cleaner lower Spectrum.
Smoother lesser 4k dip.
Sibilance reduction lowering at 9k.
Have to re-upload newer graph.


----------



## Maxx134 (Nov 6, 2021)

Forgot to say, the main difference in other "measurement rigs", would be from mids up, so that area would be more open to difference when comparing to another rig.
That's why the other (SDR) headphones is there to compare, as another "reference point"..


----------



## Maxx134 (Nov 6, 2021)

For those that may not know, I prefer to explain FR measurements   from the 1kz.

There is a reason why this point has long been chosen as a reference point in past.

It is the 1khz that you should "view" the FR for signature. To make it simple, imagine a tiny person standing on thag 1khz line, with binoculars on, and looking out to the extremes. Notice what amounts to a bass that is still at the 1khz output db level, at 20hz, so from that output, you will hear the bass at that level.

Then notice the trebles from 5k practically ruler flat to18khz, but also extending (seeing) further past that, to 23khz at that same output level of the 1khz.

All should be viewed from the 1khz level, to gain a proper impression of how the overall tonality of the headphones will be observed.

Then the pic should be viewed in relation to how the HD800 is graphed in other places, to get more perspective.


----------



## Maxx134 (Sep 4, 2022)

What is most important to note, is that _EVERY_ FR graph, not just this one, but *every single graph on internet*, of every single HD 800, or HD800S, or HD 8XX, _*all*_ have the 20hz point 5db below the 1khz point. This is fact...
My measurement shows the 20hz point "_*in same line*_" with the 1khz point, so it is a true 5db increase.
This decibel level point, is irrespective of any other headphone plotted and compared, next to it...

This results also in an extension of the sub-bass level, to notably audible levels, which is different than if you just turned up the bass on a normal unit.

I also posted more info on the trebles, in the post with the grapth.


----------



## Maxx134

Forgot to mention that I using Dekoni ferenstrated pads on this mod,

 which automatically have less bass than stock pads, so I would expect greater bass seal on stock pads..

Anyways, to offset this, use the stock pads silicone seal, as posted earlier in this thread. 👍


----------



## Maxx134 (Sep 11, 2022)

Forgot to mention that I am not using any stupid inserts inside the driver.

So since I have only used the HD800 for my mods, I realized that I have _*not*_ taken advantage of the 800S ability to give more bass...

I have not "cheated" with these center tuning inserts, that are called "resonators" lol.
I only say "cheated", as a joke, because they are not real improvements ( to me), only tuning material.
Sorry to be blunt, but I call it like it is, for clarification.
I view tunning mods as band-aid work.
So my bias clouded my view to use the 800S driver.

Anyways I will now evaluate and expose the 800S driver in this thread, to analyze any potential, before deciding which driver I will place in the demo unit.

To be continued...


----------



## JFCWTF (Dec 26, 2021)

Tried the tape (1-*"BASS Pressure/COUPLING SEAL" MOD*.)  and the 3- Rear dampening *Anti-resonance mod*. on my *HD 820,* works great. (used some sort of high school material "polyurethane foam" or something like that (comes in all colors, one size fits all!). (Found out what it's called: EVA foam).

But I want to remove the glass.
I cannot seem to find a way to remove the cap holding the glass, or how to access it. I thought the cap/cover would be unscrewable, but... it seems dead glued or something.

Can't believe this works so well, listening to my usual songs to compare by memory how better and clear it sounds now and less harsh on some frequencies (6k fixed?).


----------



## Adriano1402

@Maxx134 Do you need here EQ settings after all this mods?


----------



## musicinmymind

Willing to do all these mods, but I am not sure where to get material 

@Maxx134, can you please give me link to below materials where you ordered from. I live in Dubai, so shipping cost will be high, multiple shipping is not an option.

rubber tape
non slip shelf liner
material used for damping ring mod


----------



## Maxx134

musicinmymind said:


> rubber tape
> non slip shelf liner
> material used for damping ring mod


1- no need for the tape. Use silicone aquarium tubing. 
2- goto home improvement store for non-slip material. 
3- it is used as sound damping material for auto.


----------



## Maxx134

Currently doing some paint jobs, so took some before photos,  with all paint grinded down to the base materials,





 which are partially transparent 😯
I put unit together just to see how it look bare! 🙂


----------



## Maxx134 (Feb 13, 2022)

I have had multiple painting failures in past, with cheap @$$ home depot paint, regardless of brands they carry.
 Partially because of my mistakes of non optimal heavy application, and also, dry times of manufacturing changed (of "Rustoleum") because of change in thier "propellant", which ruined application drying.

This time,  I chose a more professional paint route:




And very fine (800&up) sandpaper for a second stock HD800 unit, that had stock paint, and so did not need to remove much, only sand surface.
So far, good results.

Check out gold metal flake covering stock paint on the small ring:



First primer, then gold flake, then glossy coats.
Change color without loosing any of the letters,  giving also a "3D" depth appearance...

The similar procedure on the black portion of the headband.



With smooth transition to champagne gold.
Metal pivot in pic has been taped.

Paint effect changes appearance depending on angle:




Whole unit gloss coated 3X after painting.
Now must let dry before assembly.

This paint applies superior to any spray can I used in past (like "home depo" brands). 👍


----------



## Ojisan

Maxx134 said:


> I have had multiple painting failures in past, with cheap @$$ home depot paint, regardless of brands they carry.
> Partially because of my mistakes of non optimal heavy application, and also, dry times of manufacturing changed (of "Rustoleum") because of change in thier "propellant", which ruined application drying.
> 
> This time,  I chose a more professional paint route:
> ...


I would think of plastic model paints, like Tamiya, before heading to Home Depot. Did you try anything like that?


----------



## Maxx134

Ojisan said:


> I would think of plastic model paints, like Tamiya, before heading to Home Depot. Did you try anything like that?


Good point. I haven't that brand.
I focused this time, on cans with best spray nozzles.


----------



## Maxx134

Adriano1402 said:


> @Maxx134 Do you need here EQ settings after all this mods?


Zero EQ. That was the goal.


----------



## Maxx134 (Feb 16, 2022)

Update:
Custom paint job completed on two HD800s.
Edit** the red one is just for comparison, as both units are gold...
One will be used for demo purposes.

Champagne gold mist with glossy topcoat:




After mod completed, I will be using the work on this unit, to compile a PDF,  complete with all pictures of my work, for the ultimate  HD800M mod.
It is a surgical process, and for those willing and able to have the dexterity to complete, it will be finally,  a true end game reference class unit.

All weaknesses improved with real micro detailed, layering, focus and true depth of field is increased, along *with real, physical/visual/technical true bass improvement.* *No material tunning shortcuts for bass...*
The red unit on the left, is the example of this final 800M mod.

No one else would dare claim this, even Sennheiser (currently) until they themselves do this, which is what I originally wanted,  but will be too late soon as I intend to finally make this public in PDF instructional format.

The big release PDF instructional will make many or all top headphones moot. Only a susvara or Abyss TC would be preferable for bass only, as as the HD800 series will never be a bass monster,  but it will finally rise to being a reference without handicaps.

So every step of the latest mod will be recorded from this unit work....
In progress. 👍


----------



## Maxx134

Some notes on the paint job:
Gold flake and topcoat was added to the silver center ring,  so as not to lose the lettering original lettering ( 300 ohms) while still changing its color to gold.



Then, matching color chosen, champagne gold, to blend in with resulting overall similar finish. 



Then glossy clear coat applied. 👍


----------



## Hman14 (Mar 8, 2022)

New head-fier here. Really cool mods -- love the work!

Sorry for the stupid question but I just bought a used 800 S as a way to get into the hobby (powered for now by a BHC I am building for some 600s I bought). Can't wait to hear them but wonder what mods, if any, you might suggest on the S model as opposed to the 800?

I hear the 800 S has some issues with EQing as well as the 800. I will at the very least try the Dekoni pads with silicon that you suggest.

EDIT: I am also going to re-paint the 800 S as it was Candy red and I am also going for similar colour in the champagne mist (rustoleum).


----------



## Maxx134

Hman14 said:


> an't wait to hear them but wonder what mods, if any, you might suggest on the S model as opposed to the 800?


I have the 800S driver that I will be testing/measuring to see how it responds to my latest modifications, so we will see.
I had other projects that slowed me down.


Also, I will not be performing any modifications whatsoever on the 8XX, because it has been double "gimped" with both a dampened driver, and a "material dampened" basket frame, which to me, is absolute engineering nonsense,  and is too much work for me to "undo"...
My sources also relayed to me potential knocking of both drivers (xmax) with medium volume sweep. That is unacceptable.


----------



## Maxx134

Hman14 said:


> EDIT: I am also going to re-paint the 800 S as it was Candy red and I am also going for similar colour in the champagne mist (rustoleum).


I do not like or recommend Rustoleum. 
I  had bad experiences with them.
Paint looks great but never dries properly. I recommend automotive spray cans.


----------



## Hman14

Maxx134 said:


> I have the 800S driver that I will be testing/measuring to see how it responds to my latest modifications, so we will see.
> I had other projects that slowed me down.
> 
> 
> ...





Maxx134 said:


> I do not like or recommend Rustoleum.
> I  had bad experiences with them.
> Paint looks great but never dries properly. I recommend automotive spray cans.



Thanks for the recommendation. I'll try out some different paints and see how it works out! 

Curious to see (maybe eventually hear) what you come up with for the 800 S.


----------



## Maxx134

Hman14 said:


> Curious to see (maybe eventually hear) what you come up with for the 800 S.


Currently making recording a comparison. Hope to have up very soon.


----------



## Maxx134

Update, I  have just completed one custom HD800"M" mod, with the champagne gold gloss paint, with the top Dekoni pads, with custom mini-XLR sockets, using custom solid silver core wiring, connected using mundorf silver/gold solder.
All Working exceptional as intended. 



I realize this mod takes longer to make than expected, so I am planning to recruit modders that have the "skill set" to do this.

Doing the mod without the gold paint job would be much easier. 

Next is to upload the sonic difference video.


----------



## Maxx134 (Sep 4, 2022)

Just another update.
I like to know who would or could claim this:

BASSSS IMPROVEMENT:

And,

TREBLE IMPROVEMENT:



....

None have done this.
Not MassDrop.
No other website modders.
Not Sennheiser

I am the _*only one*_ who has posted and measured actual improvements on same measurement setup, before and after, so it nullifies any variables of measurement differences.

The improvements I am posting,  are specifically of "_*frequency extension*_" at both ends of the spectrum. This is not some simple tunning. The driver is actually performing with different parameters. This is not just a tunning or damping mod. Also take note that any 6k peak,ringing, or diffuse sound is a thing of the past, and already addressed in previous steps, which already resulted in Lazer sharp pinpoint soundstage accuracy.

You would think the entities I listed above, would come to me for this latest modification, instead of going off on a tangent of wild material tunnings.

The door is still open to Sennheiser for the modification procedure.
It would open new doors for their engineering team. Hopefully they would reconsider,  instead of following suit years later after this mod is out.

I am in the process to make an  instructional video, and a sound demo video next. Time is running out as it will be made with or without any of them.


----------



## Maxx134 (Apr 22, 2022)

There is a topic of "tunning" which can be addressed.

The trebles amount (not extension) indeed are part of tunning aspect, which is not a problem for me to either make stock, or flatten, *without altering soundstage* as others do.


All past changes, with exception of the "Stefan Audio modded HD800" are only "tunning" modifications.

Whether it is an 800S, 8XX, 800:SD, annax, rugliner, etc.
They are a material permutations, that alter the frequency response, with varying levels of adding distortion or deadening and/or muted the sound, with most also destroying soundstage and "air".

Using materials to alter the sound, is not going towards fixing any problems. They can only mask issues.

Real improvements adress issues.
As noted, in past only the "Stefan Audio" actually addressed issue with an actual fix.

I have adressed and covered same fixes that Stefan Audio adressed, but more thoroughly with my mods in previous pages.
The topics adressed were damping and rear reflection,  which I cover more thoroughly.
His method relied on "compression damping", below the driver, and elimination of grill reflection.
I more thoroughly cover this with dual side dynamat and thin shelf liner on the rear grill...
Yet those are only two aspects covered.

Absolutely no mod or company change, had addressed the actual driver _performance_ itself.

So that is key, that my last addition to this mod adresses the driver itself to perform at new parameters.
As such it becomes closer to a
larger and deeper stage planar sound, (most similar to a susvara). It loses its artificial forward nature, and becomes natural and more effortless.

So next step is to actually show you the sound.
I have recorded the latest  HD800"M" and stock already.

In order for both to perform at their maximum potential, without earpad differences, or measurement setup, or "ear coupler" differences,  I recorded them live, with a professional stereo microphone.

The songs are recorded below 30seconds, in order to not cause copyright strike.
If YouTube decides to have issue, I will just re-upload to another platform as this is obviously only a headphone sound demo.

I plan to have it upload this coming week, so there will be no more speculations or controversies.
👍


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## Maxx134 (Sep 16, 2022)

In all my posts where I complain, there is a misleading assumption that I claim to know more than Sennheiser.

This is incorrect viewpoint that I need to clarify.
The point is, that I realized key design aspects, which apparently Mr Axel Grell never disclosed to Sennheiser engineers..
Because as history shows, they have never taken advantage of this, or just accepted the design as is.
So maybe one day I get Sennheiser to see this.


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## helloh3adfi

Hey dude, would it be bad or no sound change at all, if I do this?


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## Maxx134

helloh3adfi said:


> Hey dude, would it be bad or no sound change at all, if I do this?



I  only use the best Dekoni Ferenstrated leather pads.
Therfore I do not know if Dekoni uses the same dust cover material.

Here are the issues and conditions that would allow you to consider this:

1-The first issue, is that the human ears keep growing with age, so more space would be appreciated mainly with older people, not young people. 
2-The second issue is that there is plenty of room already for the ear,  when using the thicker pad selection I use.
3-The third issue is that it is irreversible.
4-The fourth issue is that the material Dekoni uses for the pad I use, is totally audibly transparent.
5- The fifth issue is the choice of using stock dust covers.
These stock covers do alter the sound. They may be preferred on stock unmodded headphones, as they do tame and smooth over some of the top end.
You can keep them in and use them under the Dekoni pads, if you like.

Personally, IMO I choose to never use the stock covers, as I go for maximum clarity, but I can see how it would help with excessive trebles that the stock unit has.


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## Mattyjm

Thanks @Maxx134 for the help! Couldn't have it done it without your guidance!


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## Maxx134

Mattyjm said:


> Thanks @Maxx134 for the help! Couldn't have it done it without your guidance!


Here is a "recap" of how to perform this mini XLR socket mod:

 I use hot glue inside once I get it in snug, and the very slight angle is unavoidable, but perfect angle when wearing, to position the cable away, not straight.

You will need a special drill bit I will post pics:



Using these two different tools will give you best results.. 

If you try any other tool, you will risk damaging the driver soldering points inside.

Use the specific "RYOBI" angle drill bit first, with patience and controlled easy pressure. Take your time, no rushing and no excess pressure, in order to go slow.

We use same hole, only expand it larger, and also angle drill slightly downward so that the new socket does not hit the driver. Look closely at pics.

 I also marked the "positive" in red. Positive on driver is same pin on both (L&R) sides, so not "mirrored".

Then once hole is achieved, you get a dremel to use that specific dremel tool in picture, to smoothen and widen the hole enough for a snug twist fit of the mini XLR socket.

Then insert the socket, _*with wires already soldered/attached*_,



to eliminate any soldering in small area, as that would be difficult and messy. Use the image for soldering. 
Solder the wires neatly, taking your time. 

Finally, check connections work, by plugging in a cable to test, before applying hotglue.



Apply very generously, but do not exceed the area-cavity dimensions, to not have it bulge more than space inside, 



or else the outside plastic hd800 parts will be hard to place over it.

There you go. Goodluck to anyone wanting to try this.


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## Maxx134 (Aug 15, 2022)

I haven't updated this thread in a while due to other projects.

Still have to post audio file  differences, but today I will post a direct comparison observation.

I have a friend's HD800S, to compare against my HD800M:



 I haven't had the HD800S to directly listen "side by side" with my latest  HD800M in a long time, and doing so, I am still a bit surprised.

Here are my observations:

The 800S unit was more forward, and hitting a wall, with lack of noticable depth and micro dynamics in comparison, which made my 800M unit noticably more layered in comparison.

Then there is the bass difference. I was curious to see how this 800S would hold up, but it wasn't anything like I had expected.

There was a bass, to mid bass in the 800S, which was "_masquerading"_ as the whole low end sound, but in comparison to my 800M, it was a very different experience.

 The 800M displayed an actual noticeable and integrated _*subbass*_ with dynamics* in that region, which made the music track sound very different.

Bottom line, the HD800M was an Impactful and more real low end, where as the 800S, in comparison, had no impact,  replaced by a slightly forward compressed mid bass.

To put this in perspective, this is the HD800S, not the HD800, and so I am reminded of the disappointments & frustrations of all iterations to owners.
It is a waste of what is a potentially a true end game headphones with the 800M mod, which Sennheiser should have taken up.

I will now be performing some tests and measurements, to see if I can fix the 800S driver better than the 800"M" driver.


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## Maxx134 (Sep 5, 2022)

Latest update on HD800S drivers testing and modification came at expense and loss of one driver.
It turns out that even following my latest tools, protocols and procedures, I still managed to damaged a driver.

  So my modification procedures lead to a reduced installation failure rate from 75-80% to 50%, so it's still a 50% danger rate (_*in the transformation process only*_)which means any future contemplation of moded units would necessitate an extra driver expense.

It is important to state that once achieved, the driver retains all the durability, longevity, and reliability of stock unit, in performance.

Until this issue is more fully resolved, a public disclosure cannot be done, but instead, a recruitment for skilled modders willing to learn. Those interested can PM me.

On the bright side, I finalized the HD800SM mod.
It was a pretty noticeable success.

Ok , so the good news is that I   measured  and verified an increase 2-3db across the whole lower spectrum,  with a boost of 3db at subbass of 13hz, _*over the HD800S*_ ...*not* the HD800.

Also, the traditional Sennheiser dip in upper mids had also been reduced, and also slight extended range in the upper trebles beyond 15k.

Will post some pics, video and measurements next.


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## Maxx134

Ok just did some more measurements...
Turns out my latest HD800SM mod delivers a full 6db bass increase in 15hz-20hz, over the HD800...
The bass improvement continues as almost 3db elevation at 30db. The bass improvement starts at 65hz.

More linear mids from 1-3.5khz aa well, and an extention of trebles of 20-24khz.
Will fill in this post with measurement pics soon.


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## Maxx134 (Sep 12, 2022)

Here are the measurements on the new HD800SM

*HD800SM  vs HD800:


*

_*** Full 6db bass increase, *_from *15hz-20hz*, over the HD800...
_*** *_Bass improvement continues as about 3db elevation at 30hz..
*** *Bass improvement reaches to 65hz..
**** More linear and elevated mids from 1-3.5khz, eliminating need for tube amps.
*** *extention of trebles measurement..

~~~~~~~~~


*HD800SM vs HD800S:*




_*** 2-3db boost across the whole lower spectrum*_ ..
_*** Real boost*_ *of 3db* of subbass at 13hz ..
_*** *_reduced mids dip compared to HD800S ..
_*** *_slight extended range in the upper trebles beyond 15khz ..

~~~~~~

It should be noted that all of the headphones above, were measured _*on the same setup*_.
My setup, being different as other websites, will have HD800 images a bit different as other measurement setups, *which is normal*...
 It is important to note that every website measurement has a different but similar image. 

Mine shows an excessive 4K area dip which would not show same on other setups. This is due to the usage of paper on my measument coupler, instead of any type of foam. This choice was made in order to not have loss of Upper range accuracy,  that any type foam does to kill upper spectrum. 
My usage of same rig, instead of updating "ears" coupler is due to keeping a same baseline for all my older measurements. 


When comparing images with different measurement rigs, they will start to differ somewhat, from 1k to trebles, but bass is always be very much on par with other setups.
 So there is accuracy in determination of this latest HD800SM mod to be superior in bass comparison, _*over the other Sennheiser variants currently available.

 S*ince it is not done with any frontal, basket material playing like HD8XX, there is a fundamental difference of performance improvement with HD800SM, compared to only material "tunning" changes like HD800S or latest HD8XX. 
The HD800SM takes advantage of NOT altering the frontal implementation of the 800S, which is also included in the 8XX.

****_Edit:
Will upload a 8XX comparison when I get one to test.

I also redid the flat black paint of the 800S stock paint job, to differentiate it. 👍


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## Maxx134 (Sep 10, 2022)

Video of new HD800SM paint job, done on an HD800S.
Notice no lettering is lost:



In order to get a level of painting close to auto air spray, I used paint from  "66autocolor" site. 👍


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## Maxx134 (Sep 12, 2022)

Maxx134 said:


> Will upload a 8XX comparison when I get one to test.


I happened to do a search for HD8XX unboxing, to check how package if sealed,  and came across a comparison video.
I was under the assumption that the  HD8XX was supposed to have a bass benefit,  but upon listening to this video, it turns out that the HD800S actually has a bit more subbass than the HD8XX!

I was shocked to hear this. All this whole time I was believing the effort was made to " improve" bass. So it no longer seems the case. The 8XX is just a variation of an 800S. 

I will verify myself,  if it has any real bass, instead of others images.
So far this video shows no sub bass improvement at all, which means my HD800SM will have the same substantial bass improvements of over 3db avg, across whole bass area...
So I will verify.
If anyone has an HD8XX to let me test, PM me.


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## Maxx134 (Sep 12, 2022)

I have decided to look into this, and attain a 8XX, in order to make a true conversion to 800S, and then update it to an HD800SM.
Will post measurements & pics along the way to record this here.
Edit**
After much contemplation,  I  realize it's too much work and instead will just optimize the 800S drivers, which, after more investigation, I now believe are the most robust version.


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## pbui44

So if I buy a HD8XX and lend it to you, then you will do all the mods for free AND even cover the costs for any parts that you break or kill, like the drivers?


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## Maxx134

pbui44 said:


> So if I buy a HD8XX and lend it to you, then you will do all the mods for free AND even cover the costs for any parts that you break or kill, like the drivers?


Haha you can lend it to me as the first guinea pig for testing to see what if can be done.  
It guaranteed to not be the same 🫣🙃, lol


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## Maxx134 (Sep 13, 2022)

pbui44 said:


> break or kill, like the drivers?


After much recent investigation and contemplation,  I would not replace any broken units with 8XX drivers. It is my determination that the most refined/robust driver version Sennheiser made, was the driver inside the 820 unit, which is the 800S driver.
It's just easier to work with an 800S. The 8XX would just take longer to convert. 

I am no longer convinced the 8XX driver is same as an 800S driver (with changes), because of the difference(lack) of subbass from that video.
I do know the original hd800 driver has a bit more clear membrane on the diaphragm over the HD800S,  so that would tell me clues if the 8XX version is a hybrid of either.

So I would simply consider the 8XX as another tunning alternative,  just as there are users who like the 800, or 800S. Although the main concensus it that the 8XX has a “narrow corridor” effect which can be alleviated with the basket tap removal.
The driver still has the issue of covered holes and unknown driver membrane from either an 800S or an 800. Regardless, it's a variant with similar potential.


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## Maxx134 (Sep 14, 2022)

I have just refined my modification process and ordered new tools to reduce my latest mod safety margins to estimated 90% instead of 50% or so. Have to wait till parts come in to try another mod. If this works,  my modification process can be made public.

I am also still interested in the 8XX driver so hopefully I can look into it.


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## GanGreinke

I had @Maxx134 mod my pair of HD800 into what I believe are his most recent HD800M, and I have been using them for a few months now. I was interested in his mods because I had heard a pair of HD800 that he modded several years ago and was impressed by how he tamed the treble spike and improved the bass quality and quantity. When I saw that he had further improved his mods, I contacted him and asked him to both mod and paint my headphones.

I should say upfront that I was not a fan of the HD800 stock sound. My pair are actually a lower serial number (in the 07000 range), which some people feel is the best iteration, but even then I couldn’t stand the sharp treble spike. With the full HD800M, I don’t have a problem with the treble. In addition, I feel like there is definitely a significant improvement in both the quality and quantity of the bass. It is by no means a bass cannon, but there is definitely more impact and slam in the bass region. I also think there is an improvement in the resolution, but I would probably need to hear the modded and unmodded back to back to compare. The headstage is still as expansive as it was (the combination of the Weiss Dac502 and the EC Aficionado create a ridiculously wide headstage, and it doesn’t feel gimmicky). 

I have not heard the Susvara, Utopia, or other flagships on my chain, so I can’t comment how they compare, but I can say that @Maxx134 has significantly improved the HD800. I would definitely recommend his mods if you are looking to correct the weaknesses of the HD800!


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## Maxx134 (Sep 24, 2022)

While I made the HD800SM version,  which uses an HD800S drivers, I had disected and scrutinized an HD800S driver.
So although I don't like to use these control methods, I decided since all the variants are using the center insert, I will make my own version to actually improve the Frequency response, not by muting any range, but instead the opposite, to amplify the ranges I want. This is a total opposite approach to what all other attempts have done.

So this is the latest version,  the HD800M2 version.  It does not use 800S drivers , but original HD800 drivers, to EXCEED the HD800S in all aspects.

Here is the Frequency response,  which shows my latest 800M2 having similar(tiny bit more) low end extension and boost as the 800SM, wich uses 800S drivers.
It also , and most importantly,  has the _*least dip*_ of *all* HD800 variants.
Then, as an example of the difference in design,  it also gives an extension of the trebles range, over all other variants while also being the most linear in upper range of all the 800 variants...

Here is a comparison of my latest 800M2 vs 800SM vs 800S :





The latest improvements (in green) are directly due to my own design center insert, in addition to my driver modification.

It is also important to note that my measurement coupler is not using "ears" in order to get more accuracy from lack of needing algorithms for the ear pinea. So the result shows the differences with a dip that looks different than other measurement rigs, which is normal. The differences between these headphones is what should be noted.
My measurement coupler also does not use any type of foam surface materials, which would corrupt the treble accuracy in other "non-ear" setups. 

later I will post pics to show actual impulse response improvements.👍


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## Maxx134 (Sep 24, 2022)

GanGreinke said:


> my pair of HD800 into what I believe are his most recent HD800M


I only made one version of the hd800"M".
Just this week I finished the latest version, "hd800M2", which differs only with my own version of a "center insert".
It was created using an opposite ideology of NOT hampering or muting sound, but instead "enabling" the sound, creating more linear trebles extension, with also less mids dip and elevation of whole lower range. 👍


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## GanGreinke

Maxx134 said:


> I only made one version of the hd800"M".
> Just this week I finished the latest hd800M2, which differs only with my own version of a "center insert".
> It was created using an opposite ideology of NOT hampering or muting sound, but instead "enabling" the sound, creating more linear trebles extension, with also less mids dip and elevation of whole lower range.


Is the insert something that can be easily added to my pair, or would it involve making some additional changes to install the center insert?


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## Maxx134

GanGreinke said:


> Is the insert something that can be easily added to my pair, or would it involve making some additional changes to install the center insert?


Yes, I can send you the center inserts. Installation is same as any insert. Press edge to peel up mesh halfway, stick in insert (eva side up) and replace.


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## Thobjo (Oct 22, 2022)

I have only done cosmetic mods such as coloring and  then padswap/headband. 
Your mods look very interesting, is the center insert you added links to ordering more of a benefit to the 800 than the 800s and not really needed even on a S or...?


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## Maxx134

Thobjo said:


> I have only done cosmetic mods such as coloring and  then padswap/headband.
> Your mods look very interesting, is the center insert you added links to ordering more of a benefit to the 800 than the 800s and not really needed even on a S or...?


Sorry I not around as much so viewing this post late.
The Sennheiser insert links are old version.

My latest insert adress the whole spectrum, from bass to mids and trebles, to enhance,  opposite of "damping" or muting any range. It uses a combo of specific density foam, with also synthetic fibers in order to exite the upper range.  This enhance upper spectrum and helps eliminate the scoop that the hd800 iterations have. 

Anyone interested just had to PM me. I have ordered a stockpile specifically made to order from China. Enough for a few hundred.  No charge except shipping.  I don't believe in making money on such a small item.

Also, I do not like the HD800S driver.  In my testing, which exceeds normal parameters, it will reach a limit before the traditional HD800 driver. Then it uses a thin film in center, with another thin film in bottom center, as there is not an actual physical insert, but instead these two thin material films. Probably why they call it a "resonator".. A pain to remove if I wanted to into an HD800, or use a DIY insert. The inside bottom should be left alone so you can revert when using inserts.
Also,
Then the membrane is a different clarity, denoting a different polymer material was used.
Maybe why the upper spectrum of 800S & 8XX does not go as high as the hd800.
That is why I feel it can benefit from my insert. 

Currently I just finish a paint job on my old broken pair.
Had to order new drivers for it, and luckily they had old 800 drivers, which are to me, the most robust and most capable version.


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## Maxx134

My headphone theology:

One open desktop flagship headphone for home. 
One flagship IEM for closed headphone.
One portable for convenience. 

Everything else is a waste of time and effort. 
🤫🙂

System theology:
One flagship DAP for use as both a desktop source and portable.
One tube amp for home.

Everything else is a waste of time and effort.
🙃🙂


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## rudbeard

Ok Alexa, play "Religious war" on Spotify. JK. I agree that until you've had the chance to take headphones with you, you won't understand that a desktop/home amp should have a nomadic headphone DAC/Amp. I've sidegraded around and the RME ADI-2 lives on my desk while the WA11 and IFI BL go with me places.

But no closed back? IEMs don't work for everyone. No distinction of how everyone should have a planar, punchy dynamic, and another planar (you thought I was going to say e-stat, hah).


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## aj-kun

With this much dynamat you could have added a tin foil hat on the headband


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## pbui44

aj-kun said:


> With this much dynamat you could have added a tin foil hat on the headband



...or made dynamat bowls that hang about an inch outside the HD800 ear cups and put sound deadening material inside, outside, and around the bowls.


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## rudbeard

Thobjo said:


> I have only done cosmetic mods such as coloring and  then padswap/headband.
> Your mods look very interesting, is the center insert you added links to ordering more of a benefit to the 800 than the 800s and not really needed even on a S or...?


How did you color the mesh basket and if paint, did it color the sound?


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## Thobjo

rudbeard said:


> How did you color the mesh basket and if paint, did it color the sound?


I just used some Poska Marker as it is easy to remove if wanted.

Sound is the same.


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