# Smaller Huge J-Low



## digitalmind

After building the Cyburg Stick and Buschhorn I've really gotten the DIY-flu. I'll be working on a speaker project in the new year, and figured I'd keep a log up to date with my progress here. Going will be rather slow, not so much spare moolah laying around after december. 
	

	
	
		
		

		
			





 I've recently gotten a pair of Jordan VTL speakers sporting Jordan JX92s drivers. Much impressed as I am with these speakers, I can't help but wonder what they'll do in a no-compromise design. The VTL's are great speakers to hear and see, but they are rather small, and sexy as they may be, there might be more performance in the JX92s than the VTL can deliver. 
_Insides_ pointed me to the J-Low. They won't fit in my room though, so essentially, I'll be building a slightly modified version of the J-Low. Dubbed the Smaller Huge J-Low. I'll be keeping a fairly detailed log here, in case somebody else may want to build it (and because I'd like to be able to read back later where I've gone wrong...).

*The J-Low*

 This is a design made by Nelson Pass. It's a no-compromise, back-loaded exponential horn using the JX92S that stands 1.82 meters tall, 4 cm less tall than I am. The original design is 60 cm wide -- too wide to fit my relatively small room. If I built them from the original design, I wouldn't be able to open the door to my room anymore. To get an idea of how large this thing really is, here's a small picture I nabbed off of Passdiy.com:






 Another picture from a private builder:





 Here are two PDF's with more information, including schematics and instructions on building the J-Low:
http://passdiy.com/pdf/j-low.pdf
http://passdiy.com/pdf/jlowassy.pdf

*The Jordan JX92s*

 Information on this driver can be found here: Jordan JX92S specifications
 A quote from that page:

  Quote:


 Embracing a range of almost nine octaves, the JX92S offers the widest bandwidth of any single drive unit available. This not only provides an exceptionally smooth, high-definition, crossover-free sound quality but allows for a very diverse range of applications.

 The JX92S can be successfully used with all types of enclosures including closed or vented boxes, transmission lines and horn loaded designs. It is eminently suitable for professional near-field monitors, high quality domestic hi-fi, home cinema and custom installations. The unit is magnetically screened, enabling it to be used in close proximity to computer monitors and television screens. 
 

*But why?*

 I said earlier that I wanted to see what the JX92s could be in an optimal design. That's part of the reason I want to build the J-Low. Perhaps even more important: I want to build them because they are insane! No, seriously, that is actually a large part in my reason behind building these. Hardly anyone has built these speakers because they are so wife/girlfriend-unfriendly and can't be used in a living room since guests would die of shock. Sadly (luckily in this case), I'm not being held back by a girlfriend (or wife!), and have no living room. Meaning: I can do whatever the hell I want for now, and I'll be damned if I'm not going to take advantage of that while I still can. 
	

	
	
		
		

		
		
	


	




*But they're huge!*

 Indeed. Too huge. I'm missing roughly 25 cm of space, so I need to make them slightly thinner than the original design. After some discussion with Tony from Humble Homemade Hifi he came to the conclusion that it's possible to make them about 15cm's smaller without effecting the sound. The only effect it is likely to have is a slightly less large contact area with the room, which could result in less bass presence and slam. This is hardly an issue in my small room, as they are more than large enough to provide all the slam I'll ever need. The room _will_ be dominated by these speakers anyhow. So, they'll become 45 cm's wide instead of 60 cm, and will be just as tall and deep as the original design. 

*The schematics*

 I've modeled the SH-J-Low in Sketchup. 
 You can grab the Sketchup file here, if you want: http://www.iamrik.com/jlow/jlowslim1.skp

 The schematics are based on 18 mm material. I'll be working pre-veneered 18 mm MDF. MDF is brilliant for making speakers. A very strong material and easy to work with. 

 The top and bottom part mismatch with 1mm since the original design is based around 19 mm (3/4") material. On a speaker this large, I'll be ignoring such a small difference. I can redo the schematic to make up for this single mm, but frankly, I can't be bothered. 




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 That's it for now. Expect updates in this thread in the beginning of January.

 Signing off to get insanely drunk and wake up sometime 2008 quite possibly in a ditch, under a bridge, or worse. Have a great new years eve folks!


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## digitalmind

What do you know, didn't even wake up in a ditch or under a bridge. 

 Local DIY store here sells decently (fake)veneered MDF in 2.5m x 60cm 18mm panels, so I made a panel schedule. That's 3mm less deep than the original drawings, but on 60cm that can be neglected. I'll need 7 panels in total for two speakers, giving me a bit more than half a panel spare. A panel of some light colored wood (completely forgot the name) is €25 per panel, and a sexy dark one is €35. Comes down to €175 - €245 in wood, depending on which one I go with. Haven't made up my mind.


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## swt61

Cool Rik!

 I'll be following this build. Not sure those are the right size for my own build, but it's great that you decided to document the process this time.


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## JadeEast

I've been curious about this design as well as the other double horns and the BIB designs being built. I'd love to play with one of these and maybe mount the driver on the side to load the corners more and get away with a bit more of a flush design and take advantage of the wide baffle. Being an apartment guy I'll just screw around with headphones right now and watch.

 Go big.


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## digitalmind

Quote:


  Originally Posted by *swt61* /img/forum/go_quote.gif 
_Cool Rik!

 I'll be following this build. Not sure those are the right size for my own build, but it's great that you decided to document the process this time. 
	

	
	
		
		

		
		
	


	


_

 

Thanks, I'm not all that sure about the size yet either, but we'll see where this goes. Either I end up with huge speakers in my room, or I have a lot of wood for the fireplace. 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *JadeEast* /img/forum/go_quote.gif 
_I've been curious about this design as well as the other double horns and the BIB designs being built. I'd love to play with one of these and maybe mount the driver on the side to load the corners more and get away with a bit more of a flush design and take advantage of the wide baffle. Being an apartment guy I'll just screw around with headphones right now and watch.

 Go big._

 

The BIB design is also something that appeals to me, especially since a lot of people have built it and most of them are very satisfied. 

 What you said about expirimenting with the driver location.... it should be easy to make a switchable Fb so I could play with the driver location. Will give this some thought, great idea. 



 Made a huge mess of things in the earlier panel schedule so I removed it from my post. Here's the new one, including a Visio drawing of what goes where on the panels. 




 [size=xx-small]Click image for HTML file[/size]
[size=xx-small]Click here for Excel file[/size]


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## retaeht

Hi

 Good luck to your build! I'l be watching with greatest interest.

 J-low is what I would like to have(or actually the kleinhorn
	

	
	
		
		

		
		
	


	




).Unfortunately my space for speakers is limited by hight.The MLTL 48" is as tall as I can have for now.

 Once you have finished,please let us know how they sound compared to VTL.


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## digitalmind

Quote:


  Originally Posted by *retaeht* /img/forum/go_quote.gif 
_Hi

 Good luck to your build! I'l be watching with greatest interest.

 J-low is what I would like to have(or actually the kleinhorn
	

	
	
		
		

		
		
	


	




).Unfortunately my space for speakers is limited by hight.The MLTL 48" is as tall as I can have for now.

 Once you have finished,please let us know how they sound compared to VTL._

 

Hi, thanks. 

 I also would love to have something as large as the Kleinhorns -- but that'll most likely never be possible. 
	

	
	
		
		

		
		
	


	




 Do you have the MLTL 48" with Jordans, or are you thinking about making them? I may build a set out of MDF just because it's such an easy build and there's a bunch of very favorable commentery on them. 

 I'll definitely get a review/comparison between the J-Low and the VTL. I may not have both of them playing at the same time for a while though -- I only have one set of drivers.


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## retaeht

Quote:


  Originally Posted by *digitalmind* /img/forum/go_quote.gif 
_Hi, thanks. 

 Do you have the MLTL 48" with Jordans, or are you thinking about making them?_

 

I already have them.With some BSC and toe-in the sound is quite nice.But it would be interesting to hear J-low.

 I think your approach in making them not so wide is also more pleasing to an eye,they are still huge.


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## digitalmind

Quote:


  Originally Posted by *retaeht* /img/forum/go_quote.gif 
_I already have them.With some BSC and toe-in the sound is quite nice.But it would be interesting to hear J-low.

 I think your approach in making them not so wide is also more pleasing to an eye,they are still huge._

 

I'm not very knowledgeable about BSC's. I just keep moving the speakers untill it sounds right. Since I can't play with the placement of the J-Low's at all, a BSC might be fun to mess around with. Are you using a filter before your amplifier? 

 Toe-in could become an issue with the J-Low's. From my experience, the JX92s sound best when crossing in front of the listening position (which corresponds to them being designed for a 30+30 degrees toe-in). This isn't possible for me with the J-Low, as it's a very tight fit in my room and they will have to be with their backs flat against the rear wall. I hope the large size of the speaker and horn mouths make up for the lack of toe-in. Two things can happen: speakers sounding too bright (though I doubt that'll happen since they are fairly bass heavy speakers), and loss of imaging. Will this be a problem? I dunno, hope not. Haha, not exactly rocket science this... just build them and hope they don't sound too awful. I'm liking that approach. 
	

	
	
		
		

		
		
	


	




 I have decided to make a J-Low from plain 18mm MDF first, before going with pre-veneered wood. It'll give me the possibilty to mess around with stuffing in the area behind the driver (keeping one side of the J-Low screwed-only, so I can easily take it apart and adjust if needed), and it gives me a bit of practise to avoid messing up a bunch of nice wood.


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## retaeht

Quote:


  Originally Posted by *digitalmind* /img/forum/go_quote.gif 
_ Are you using a filter before your amplifier? 
_

 


 Yep,between the preamp and amplifier,a simple BSC with few resistors and a capacitor per channel.I have also used a cheap passive filter at the speakers,it doesnt sound quite as good as line level filter.And it takes some of the eficiency down.The good quality coils are so expensive I haven't tried those.

 I have actually listened my Jordans a lot also with toe-out, ap. 90 decrees from the back wall.In my room the speaker placement is a bit problematic,they are located under my bed...well the bed is about 50" high
	

	
	
		
		

		
		
	


	




.
 The sound is more lively with toe-out and also more dynamic.
 So maybe the J-low will sound nice too without the recomended toe-in.


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## digitalmind

Quote:


  Originally Posted by *retaeht* /img/forum/go_quote.gif 
_Yep,between the preamp and amplifier,a simple BSC with few resistors and a capacitor per channel.I have also used a cheap passive filter at the speakers,it doesnt sound quite as good as line level filter.And it takes some of the eficiency down.The good quality coils are so expensive I haven't tried those.

 I have actually listened my Jordans a lot also with toe-out, ap. 90 decrees from the back wall.In my room the speaker placement is a bit problematic,they are located under my bed...well the bed is about 50" high
	

	
	
		
		

		
		
	


	




.
 The sound is more lively with toe-out and also more dynamic.
 So maybe the J-low will sound nice too without the recomended toe-in._

 

You've convinced me to start messing with a BSC. I'll make a simple pot-resistor-capacitor BSC for between my preamp and poweramp, and see what the effect is. I've never been a fan of additional filters and such, but it should be fun to experiment with it. I do like the idea of having the filter before the poweramp, instead of after, as it reduces costs quite a bit and doesn't affect efficiency. 

 I've also had the Jordan VTL's at 90 degrees against the rear wall -- and I didn't like it as much as with roughly 25 degrees of toe-in. Placement seemed to have gotten worse, but the sound was more dynamic as you describe. I can do without the precise placement though, if the rest of the sound of the J-Low is an improvement over the VTL's.


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## digitalmind

Bought the wood today. A bit later than I had hoped, but school got in the way of starting last month. Decided to make them from plain MDF first before going with preveneered wood. MDF came out cheaper than I expected -- the MDF for both speakers cost me €90. I'm using four panels of 244cm x 122 cm of 18mm MDF. How I'm going to get the finished speakers out of the workshop, into the house, and then up a flight of stairs, I have no idea. I'm using a calculated *170 kg (~380 pounds)* of MDF. A single speaker will not only be pretty much as tall as me, it'll weigh even more. 
	

	
	
		
		

		
		
	


	




 Pictures later! Also a new panel layout for the MDF.


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## Bjornboy81

wow...those things are huge for such a small driver! Very cool 
	

	
	
		
		

		
		
	


	




 I wish I had the equipment to build large speaker boxes. I'd love to get into to the single driver thing.


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## digitalmind

Quote:


  Originally Posted by *Bjornboy81* /img/forum/go_quote.gif 
_wow...those things are huge for such a small driver! Very cool 
	

	
	
		
		

		
		
	


	




 I wish I had the equipment to build large speaker boxes. I'd love to get into to the single driver thing._

 

Not all single driver speakers are so big! There are plenty standmount designs too (though I doubt their level of bass...).

 Here's some images of the work so far:





 That *just* fit. 





 Where the magic happens. Notice the clean floor.





 Have to saw some angles.





 Angle sawing done!





 No more clean floor 
	

	
	
		
		

		
		
	


	




.





 Big!





 Big!


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## Kees

Nice work!
 It somehow seems appropriate to wallpaper them when they are finished....


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## digitalmind

Quote:


  Originally Posted by *Kees* /img/forum/go_quote.gif 
_Nice work!
 It somehow seems appropriate to wallpaper them when they are finished....
	

	
	
		
		

		
			



_

 

Haha, great idea!






 I was considering making another pair in preveneered wood once I have a good sounding MDF version. However, I might just spraypaint these should they end up decently.


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## digitalmind

Another day in...





 Glueing corners isn't easy. Rubberbands are a great help though.










 Result so far. I plan to do some expirimentation with different drivers, so I made the front baffle holding the driver switchable. I can just unscrew the front, and screw a different one containing a different driver in place. The baffles which fall in place are already made, but don't contain driver holes yet. 

 The center pieces are all done and glued together (aside from the driver baffle) -- just not glued to the side (yet).


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## swt61

Wow! Fantastic Rik! Not only are the speakers turning out amazing, but I love seeing pics of other workshops. That's a very unique looking table saw, I don't think I've ever seen one quite like it. The table pivoting instead of the blade is a cool idea. It makes me wonder what tools from other countries I'm missing out on. If you think I collect audio gear, you should really see my tool collection. 
	

	
	
		
		

		
		
	


	




 Again fantastic work man! Please post more pics buddy.


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## digitalmind

Quote:


  Originally Posted by *swt61* /img/forum/go_quote.gif 
_Wow! Fantastic Rik! Not only are the speakers turning out amazing, but I love seeing pics of other workshops. That's a very unique looking table saw, I don't think I've ever seen one quite like it. The table pivoting instead of the blade is a cool idea. It makes me wonder what tools from other countries I'm missing out on. If you think I collect audio gear, you should really see my tool collection. 
	

	
	
		
		

		
		
	


	




 Again fantastic work man! Please post more pics buddy._

 

Steve, thanks. The workshop was much nicer as it previously was though, in a seperate room with proper ventilation, larger floorspace and better heating. The workshop was transformed into a dedicated HT though, so the tools and benches were moved to the garage. 
 I also like checking out other workshops, there's something oddly personal and fascinating about them. Also, tools are just as much fun as audio gear. 
	

	
	
		
		

		
		
	


	




 The table saw looks unique? Maybe that's because of this:





 Ok, table saw...





 What the?





 BOOM! Belt saw! 
	

	
	
		
		

		
		
	


	




 Haha, it's a great tool. However, changing from table saw to belt saw requires a rubber belt to be changed inside, and it spends most of it's time as a table saw. However, it beats not having a belt saw at all. 
	

	
	
		
		

		
		
	


	








 Milling out the driver compartment. 





 More of the same.





 Glueing the last part of the front piece. The rest of the parts can be seen on the right.





 Glueing the top in place. I can only do one piece at a time since I only have three large enough clamps. 
	

	
	
		
		

		
		
	


	



 It's not glued to the rear plate yet -- it's only clamped to it to make sure it stays at 90 degrees while the glue dries.





 All that's left over from the huge amount of MDF I started with...


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## digitalmind

Oh look, it's an almost finished J-Low! 
	

	
	
		
		

		
		
	


	




 Edit, ok, _now_ it's almost finished.










 Glueing front piece of second speaker.

 The first will be playing tomorow! 
	

	
	
		
		

		
		
	


	



 Hope to have the second one done on Sunday.

 Edit: tomorow has become today, and the first is singing!






 Holy crap the bass! There's tons of it. I'm thinking 'very cool', but am afraid what'll happen once I get the right channel playing too. I'm afraid there'll be way too much bass. Nothing that can't be fixed with a simple filter though.


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## digitalmind

Taadaa! 
	

	
	
		
		

		
		
	


	




 I'm getting used to the amount of bass. While it's definitely bass heavy at this point, it's not _very_ bass heavy. They have a very 'live' sound to them, which I'm loving. They improve on the Jordan VTL's in exactly the way I had hoped they would. Very satisfied. So much, that I'm thinking about turning them into an 'all out' speaker. 
 I've shot Nelson Pass an email with a couple thoughts about some modifications/additions to the speakers that I'm thinking about doing. I really like these and I wonder how far I could take them.


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## Kees

Nice work!
 Must have been a hell of a job to get them upstairs!
 What kind of modifications do you have in mind?


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## digitalmind

Quote:


  Originally Posted by *Kees* /img/forum/go_quote.gif 
_Nice work!
 Must have been a hell of a job to get them upstairs!_

 

It was a tight fit, and pretty damn heavy. We managed though. 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Kees* /img/forum/go_quote.gif 
_What kind of modifications do you have in mind?_

 


 I'm thinking this:






 Followed by a horn tweeter on top crossing over at somewhere between 5-7Khz:






 After that, *maybe* a large woofer for the area under 50Hz. 

 Crossover would be done either passive or active, I'm not too sure yet. I like the idea of active and biamping. I want to see if I can turn the J-Low in something that'll last me years. The J-Low using the JX92s would be the perfect basis for such a speaker, absolutely brilliant sound from mid-low to pretty high. Augmenting the highs and the lows at the very top and very bottom would turn it into something very special, I think.


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## Kees

Interesting.
 Matching drivers will be a whole new challenge!


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## digitalmind

Quote:


  Originally Posted by *Kees* /img/forum/go_quote.gif 
_Interesting.
 Matching drivers will be a whole new challenge!_

 

Indeed it will be. I know nothing of horn tweeters and compression drivers, other than that building a horn tweeter will be loads of fun. I love a 'live' sound, which is also part of reason for being interested in them.

 Edit:

 On wheels now!


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## digitalmind

Huh what? 

 Added Seas 22TAF/G tweeters as per a recommendation from someone when I talked about adding tweeters. Have them crossed over with 6dB/octave @ 3kHz. Going to play with that a bit, as well as actual placement before I can say much about it. Also, the tweeters are new so they need a couple hours...


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## digitalmind

Looks much better that way, and should also sound better. I'm creating a new 12db/octave crossover for it at a higher frequency than it is set at now. Thinking about going as high as 5kHz...


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## Clutz

Oh my god I want to move to Holland (I'm half dutch anyway- and hey, if you aren't dutch, you aren't much!) and move into your room.

 My fiance said I can build them in our new house (moving in a few months) and keep them in the boys room.

 So excited.

 Mind if I inquire as to the total costs?


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## digitalmind

Quote:


  Originally Posted by *Clutz* /img/forum/go_quote.gif 
_Oh my god I want to move to Holland (I'm half dutch anyway- and hey, if you aren't dutch, you aren't much!) and move into your room.

 My fiance said I can build them in our new house (moving in a few months) and keep them in the boys room.

 So excited.

 Mind if I inquire as to the total costs?_

 

Fine, but you're getting the couch. 
	

	
	
		
		

		
		
	


	




 I never really added everything up, but it's always more than you think before starting the build. However, these are pretty doable on a small(ish) budget...

 Note that I already had the JX92s's since they were used in a different speaker. 

*Drivers:*
 Pair of JX92s: €440
 Pair of 22TAF/G: €75
_Total drivers:_ €515

*Crossover parts: *
 Decent quality air core coils and caps: €50 (expect this to triple with the new crossover)

*Various:*
 4 pairs of speaker terminals: €25
 MDF: €100
 Wheels: €20
 Various bolts, screws, wood glue, solder, etc: €~60
 Dampening material: €25
_Total various:_ €230

*Total:* €~800
 Add some filler and paint and it should be possible to keep it under €1000 for the pair. That's not all that bad. It does cost a lot of time though, but that's a large part of the fun. 
	

	
	
		
		

		
		
	


	




 Without the tweeter (which makes for a perfectly adequate speaker, the tweeter isn't a necessity!) it'll total around €650 without finishing. The speaker was originally designed for full range use without a tweeter.

 The big investment is in all the tools to make them.

 I wish I had a large room so I could give them the air and space they really want. Though with a bit of tweaking, I shoud be seeing good results in my small room too.


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## BigJohn

Awesome Rik!
 Very nice work and thinking 
	

	
	
		
		

		
		
	


	



 I've allways been interested in single driver speakers myself because of the sensitivity and the "live" feel they can give.
 I'm not sure what it is with very sensitive speakers... 
	

	
	
		
		

		
		
	


	



 They make sense to me somehow! 
	

	
	
		
		

		
		
	


	



 (yeah yeah, I know... how did I end up with the Dyn's then..? they allso do some things very well... 
	

	
	
		
		

		
		
	


	




 )
 I not sure about the added tweeters and horns and woofers though... 
	

	
	
		
		

		
		
	


	



 I think I would like to keep it basic 
	

	
	
		
		

		
		
	


	



 But it's a great way to get experience that way and learn.
 And a fantastic way to enjoy your hobby even more than you allready did!


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