LE15A/375/075 Box Design [Archive] - Lansing Heritage Forums

Val

09-09-2005, 11:41 PM

I've re-surrounded the LE15A's, read the books, wasted WAY too much time browsing this site and have knocked out a box design for my beloved drivers. I've decided to post the design in hopes that smarter people will point out dumb things before I start cutting wood and wasting even more time!

My design factors are this: Make them small so my lovely wife will let me put them in the living room (they will be stereo speakers). Make them simple to build (no time for fancy joinery). Don't spend too much money. Vertically align the 075 and 375 for better imaging. I'll be using 1" MDF. I've used WinISD for the math.

Comments welcome! Thanks.

Zilch

09-10-2005, 12:14 AM

BaseBox 6 Pro says you want your box tuned to 32 Hz, with 4" duct length 4.25".

Do you have enough room for the dispersion lens there? It's not shown....

Val

09-10-2005, 12:19 AM

Mr. Widget

09-10-2005, 09:42 AM

You may want to try a 5.75" length duct as well and subjectively compare them. It will give you a slightly lower tuning ~30Hz... depending on your room and your own listening tatses, you may prefer the slightly lower tuning. You gain a tiny bit of deeper bass with the lower tuning.

Widget

toddalin

09-10-2005, 10:53 AM

I would mount the drivers in a verticle array rather than off-set.

GordonW

09-11-2005, 07:49 AM

I would mount the drivers in a verticle array rather than off-set.

I agree with this sentiment; though, I could see mounting the midrange and treble drivers say, one inch off center, to break up diffraction modes just a bit. You don't want the acoustic centers that far off of the vertical line through the center of the woofer, since it does go up to around 1KHz...

If you were to move your port upward, to where it was next to the 075, you should be able to accomodate this driver arrangement. Personally, that's what I'd do.

Also, if you offset the drivers, naturally be sure to "mirror image" the cabinets. This will definitely help imaging/soundstaging perception.

My only other suggestion would be to use the 077 or 2405 slot tweeter, rather than the 075... but with the drivers you've chosen, this is probably about the ideal arrangement.

Oh, one other thing comes to mind- you may want to use a "u-bolt" large enough, to clamp the 375 to the brace. Something like a very large muffler clamp U-bolt (probably available from anywhere that does truck or high-performance automotive exhaust systems) or the U-bolts made for large wiring or plumbing conduits should work. Just attach a couple of L-bracket to one side of the brace, and feed the U-bolts through the holes in the L-brackets, to clamp the unit down. This will prevent any side-stress whatsover, in ANY direction, on the front of the horn...

Regards,
Gordon.

Zilch

09-11-2005, 10:51 AM

If you move the mid and high drivers in line, use dual, smaller ports either side of and belowish of the 375.

That'd be two 3" ducts 5.75" long (best choice), or two 2.5" ducts at 3.5" long for the 32 Hz tuning (Orchid).

For Widget's 30 Hz tuning, it's two 3" ducts at 7.0" (Blue).

Your original tuning (~36 Hz, actually,) in Black.

All of the proposed tunings are the same at 40 Hz. Me and Widget are gettin' you a leetle more bass extension, is what.... :D

rloggie

09-11-2005, 11:19 AM

Hi,
I believe the lens you would want are L91. You may want to check out this Ebay auction.

http://cgi.ebay.com/JBL-L91-HORN-SPEAKER-LENSES_W0QQitemZ5806214477QQcategoryZ73372QQtcZpho toQQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Good luck.

Zilch

09-11-2005, 11:38 AM

Jeez, $144. Time to clean some up around here.

Why'm I sittin' here lookin' at these dusty things...? ;)

toddalin

09-11-2005, 11:42 AM

Yes, I think I have enough room. I believe the footprint of the acoustic lens is about 4" x 10". I've been looking for a pair but haven't found any (I probably couldn't afford them anyway :(

Thanks for running the BB math. It's probably better than WinISD.

I have a couple of the HL89 horns with the folded chamgagne-colored lenses (Hartsfield horns) I would part with. The lenses are normally 19.75" wide, but one was cut down to 15.825" and other has a cut on one of the plates at this same 15.825" width. (These were cut to fit the former owners cabinet but I guess he had second thoughts on the second.) This is still several inches wider than the horn opening of 9" with a 10.5" mounting flange. The horns are in fine shape except that the prior owner filled in a couple of the mouning holes with putty (easily removed). They have a depth of 12" if you rear mount them and about 11.75" if you surface mount them. The driver has a depth of 5.25" so they should just fit your listed cabinet depth.

If you cut the both to 15.825" you would have no problem fitting them on your baffle and would have something unique and different than anyone else.;)

rloggie

09-11-2005, 11:48 AM

These may work better.:D :D

http://cgi.ebay.com/JBL-L91-Acoustic-Lenses-NIB-Pair_W0QQitemZ5807825162QQcategoryZ3284QQtcZphotoQ QrdZ1QQcmdZViewItem

Jeez, $144. Time to clean some up around here.

Why'm I sittin' here lookin' at these dusty things...? ;)

Val

09-11-2005, 09:15 PM

Thanks for all the suggestions. I've updated the drawings to move the 075 and 375 1" off center, put in two 3" x 7" long ports and anchor the 375 with a gianormous u-bolt. I've also penciled in where an H91 might one day go (one can hope). I will mirror image them.

Thanks for the ebay links on the L91's. I'll keep an eye on the cheaper ones but they will probably go out of my pathetic range in a few days. I did ponder the H89 solution. Mounting those monsters would be pretty cool but would not pass the "In my living room?!?!" test.

I'll be using 1"MDF. Do you think the baffle will be too weak around the ports? The inner circle on the LE15A indicates the cut-out.

Thanks again for all the input.:applaud:

Zilch

09-12-2005, 12:39 AM

L200's are laid out like what you have. See my Avatar. They're made out of 3/4" MDF.

I believe that the woofer and horn frames strengthen the baffle once mounted.

It's difficult to brace between the ports; the concern is legitimate.

How do we feel about moving the ports into the upper corners?

Robh3606

09-12-2005, 04:22 AM

Why are you keeping the ports on the baffle?? Unless they are going to be shoved up against the wall you could always drop them on the back panel.

Rob:)

Val

09-12-2005, 07:24 AM

Val

09-12-2005, 09:48 PM

Jeez, $144. Time to clean some up around here.

Why'm I sittin' here lookin' at these dusty things...? ;)

Sold for $210!:blink:

Zilch

09-12-2005, 10:06 PM

:nutz:

GordonW

09-13-2005, 11:08 AM

I've thought about putting the ports up top on the front. I'd like to avoid that if I can as I'm thinking I will only cover the LE15A with a grill. I like looking at the 075 and 375/L91 and will leave them exposed.

I like the idea of back mounting the ports. If I do so, how far should the cab be kept from the wall? Now that space is not an issue is it better to go with one 4" port rather than two 3"?

Hmmm. 3/4" mdf is easier to get and work with. Is it overkill to go w/1"?

Shouldn't be a real issue, two ports vs. 1. Though, IME, multiple small ports have less problem with "port chuff" noise, than one large port of the same area. Something about flow velocity differentials across an area, AFAIK...

And, with an LE15, a rear-mounted port might help "augment" the deepest bass. Might help extend the effective in-room f3 a few Hz lower. Be prepared to use a slightly longer port than calculated, though...

Regards,
Gordon.

Regards,
Gordon.

Val

09-15-2005, 09:19 PM

"port chuff" noise

Gordon...that cracked me up...port chuff! Very descriptive. I'll take your advice. I don't want no stinking port chuff in MY living room! It's bad enuf to have to listen to the cat hurk up the occasional fur ball.

I really like the design now. It might even be final. Time to buy materials. I appreciate all the comments. I'll take pictures of the build.

GordonW

09-16-2005, 07:36 PM

If you really want to potentially "amp up" the low-bass output of the port, put 'em near the bottom of the back panel. Closer they are to the wall/floor junction, the more "acoustic gain" the ports will get. With the f3 of these being rather high (compared to typical 'modern' speakers), it might help "fatten them up" a bit. However, as I mentioned before, do be prepared to try longer ports than predicted... I've wound up cheating the port frequency lower than the box program recommended, just to "balance out" things, so that I didn't wind up with a surplus of "upper bass" (ie, between 50-100 Hz)...

Regards,
Gordon.

Val

12-30-2005, 05:26 PM

I've built the first of the two boxes described in this thread. I am very happy with the way it soundshttp://audioheritage.org/vbulletin/images/smilies/bouncy.gif. Waiting for the insulation to come so I can finish it up. I'm on to details like feet. I'd like to ask for opinions on speaker spikes. Are they worth the trouble and expense? My boxes are about 4cu ft and weigh a ton. They will eventually sit on hardwood floor in my living room.

yggdrasil

12-30-2005, 05:58 PM

I would not go for spikes. Spikes can make serious damage to your floor and anything else it comes in contact with when mounted on such heavy speakers.

edgewound

12-30-2005, 07:35 PM

I'm with Johnny on that one, Val. If you must decouple from the floor, you could use rubber feet or Anti-vibration leveling mounts from Sorbothane (http://www.sorbothane.com/)....since your cabinets weigh a ton.

mdlupke

12-31-2005, 10:38 AM

Congrats on your project, Val! Look forward to seeing images. What are your ports made of, and how are they attached? If they were mounted with a plate and screws to the outside of the speaker cabinet, you could experiment with tuning by sliding in pipes of different lengths (all the same diameter) without having to disassemble the box.

MDLupke

grumpy

12-31-2005, 09:27 PM

nice project! might want to consider building a pair of short plinths to set them on...
it would let you play with the idea of leaning the fronts back slightly so those
bullets aren't pointed at your knees :) Furniture feet under the plinth could help keep
the hardwood floor from getting damaged. Pics would be nice if possible.

Happy New Year!

-grumpy

Zilch

12-31-2005, 11:02 PM

Is the purpose of spikes to couple to, or de-couple from, the floor?

grumpy

12-31-2005, 11:21 PM

Other than epoxying it to the floor, I can't imagine a method more likely to couple
a horizontally vibrating structure to a floor :blink: In the case of a hardwood floor
(if not over a concrete slab), this can cause interesting sympathetic vibrations
...and not necessarily from your significant other. One of those things that are very
installation dependent...

Val

01-02-2006, 12:22 AM

All the reading I've done on spikes has been from people selling them and so is biased. If I understand correctly they are to anchor the speaker firmly to the floor so the speaker box has a firm footing to "push" against. I appreciate the comments and plan to pass on the spikes. I've yet to weigh the boxes but think they will be well over 100lbs.

Grumpy, what's a plinth?

I'm using 3" abs for ports from Home Depot. They are not permanently anchored yet. Once I get them tuned I'm planning to glue them in place. Currenty they force fit into 3 1/4" holes in the back that are not routed all the way thru. I'll include pics soon. It would have been a good idea mount as mdlupke suggests...oh well.

I apprecate the comments. Pics to follow.

jbl4ever

01-02-2006, 01:49 AM

Hello Val, try some run of the mill hockey pucks. Available at most sporting goods stores. A bag of 12 about $10. Counter bore 1 side to accept a 1/4x20 Tnut about 1/2'' deep. Using a C-clamp to set them. These seem to work good for me on granite floors:)

grumpy

01-02-2006, 04:37 PM

somehow, I knew that would bite me... just a base to set something on,
like under an architectural column (in this case, picture a box with no top
or bottom that's slightly lower in the back if you find angling the speakers
back helps). I like how they look when a bit smaller than the cabinet
dimensions.

-grumpy.

Val

01-02-2006, 04:58 PM

Thanks for the plinth description. I like the puck idea as well. Thank you.

Val

01-02-2006, 05:01 PM

Here is a view of the front. I used 1" MDF. I bought it at Southern Lumber in San Jose. Enough for two cabinets cost $110. This included them cutting it in their mill shop. That was the smartest thing I did all year. They say they cut within 1/8", but by my measurements they nailed every cut.

Val

01-02-2006, 05:06 PM

Here's a view of the back with the 1/4-20 anchors backed out. The back anchors to 2x2 frame and T-Nuts. I used black oxide 1/4-20 sockets throughout. I got them at Fastenal.com. Great place for fasteners.

Val

01-02-2006, 05:09 PM

As you can see I'm waiting for the delivery of the Wrap-On insulation (as recommended). Is it here yet? Is it here yet? Is it here yet?

Val

01-02-2006, 05:13 PM

I mounted the dividers with 10-32 T-Nuts. That's oxgen free (I pretend it makes a difference) 14ga RCA audio wire. Home Depot sells it for $14 for 50 feet. I tinned the ends. I selected 14ga as it was the biggest that would fit in the JBL terminals.

Val

01-02-2006, 05:18 PM

Here's a shot of one of the two ports from the outside and inside showing the rabited (sp?) mount. I am now officially in love with plunge routers and circle jigs. A friend loaned me his Port-Cable plunge router with a large circle jig. I used this for the LE15A whole. I then bought a small circle jig from Wood Crafter for about $30. Money well spent. I used the small jig for the 375, 075 and port wholes.

Val

01-02-2006, 05:21 PM

All exterior joints are simple butt joints with no fasteners. I used a bunch clamps and Tightbond II glue. After removing the clamps I then glued in these corner braces and secured them with brads (using a brad gun...very handy...just like Norm Abrams).

jbl4ever

01-02-2006, 05:27 PM

Hi Val, they look nice. What are you going to finish the cabinets with. Furniture grade laminate or paint

Val

01-02-2006, 05:29 PM

There are two vertical kiln dried 2x4's to stiffen the sides. I used these great screws from OSH called Spax to attach the 2x4's along with some Liquid Nails. The Spax fasteners are like dry wall screws but are stronger and designed for MDF (among other materials). To the vertical braces I attached another 2x4 to support the ginormous 375 magnet structure. Then, taking GordonW's advice, I fashioned a U-Bolt from 10-32 threaded rod covered with shrink tube. I used jell-nuts so they won't loosen under stress. The cross brace also further stiffens the enclosure.

Val

01-02-2006, 05:33 PM

Somewhere I read that you can get clean corners by glueing up with about 1/16" overhang. After the glue sets you come back with a cut-off bit in a router and trim off the excess. This turns out to be a way cool way to obtain an nice corner.

jbl4ever

01-02-2006, 05:39 PM

If you paint them you might want to use a 1/4 round router bit to soften the hard edges.

Val

01-02-2006, 05:40 PM

Val

01-02-2006, 05:41 PM

I'm getting some whistle around my 075. How do you seal those?

jbl4ever

01-02-2006, 05:43 PM

Val, check this out. www.plasti-kote.com (http://www.plasti-kote.com) for some spray stone finishes and colors

jbl4ever

01-02-2006, 06:03 PM

Val, as far as I can see you should use mounting bolts thur the front to nly lock nuts on the back plate. MDF does not hold screws very well with any kind of tension. Did you tighten in the cross pattern configuration

grumpy

01-02-2006, 07:10 PM

err... that's just what they sound like :D... (sorry for the joke)

o-ring from jblpro ... or home depot

might use a round-over (1/4"?) on the port holes. looks great...less "chuffing" :)

-grumpy

toddalin

01-02-2006, 07:18 PM

That's oxgen free (I pretend it makes a difference) 14ga RCA audio wire. I tinned the ends. I selected 14ga as it was the biggest that would fit in the JBL terminals.

I use 12 gauge in mine. What I did was to well tin the ends with silver solder, then grind down the circumference a little on the bench grinder until the hardened ends fit in the terminals.

As for color ideas:http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/speaker1.jpg

These cabinets were in terrible shape and I had to rebuild the bottom-front portion of one that was busted out and the wood was missing. I didn't want to veneer them so I filled in the grooves and rounded the front edges as it was easier to make it match the repaired area.

These were finished by first painting the cabinet grey. Linda did a spatter of white then took a can of the faux marble finish and lightly strayed it, then wiped/smeared the color into the grey. They really go with our modern decor.

grumpy

01-02-2006, 11:00 PM

here's what I meant by 0-ring (not associated w/ seller)... white in this picture:

http://cgi.ebay.com/JBL-Gasket-for-077-075-076-drivers-NEW_W0QQitemZ5847127682QQcategoryZ50597QQrdZ1QQcmd ZViewItem

Val

01-02-2006, 11:10 PM

Did you tighten in the cross pattern configuration

I'm not sure what you mean. The cross member that supports the 375 is screwed and glued to the vertical braces.

jbl4ever

01-02-2006, 11:27 PM

The mounting bracket for the 075. Slowly tighting the screws in a crisscross pattern. Are the mounting plates threaded or smooth bore no threads

John W

01-03-2006, 09:42 AM

I plan to finish them with paint to match our living room (maximizing the WAF). Dutch Boy makes some textured finishes that I think I might try. I'm open to suggestions. I've decided that my life is too short to take on vaneer. I will be rounding the corners with a 1/2" roundover bit.

Very nice project.
I would try walnut veneer on the sides rather than paint, and JBL Blue on the front. Applying veneer, especially paper-backed veneer, is not especially difficult and really pays off.
Also, I know my wife is never really happy until there is a front grill covering the drivers.

toddalin

01-03-2006, 10:23 AM

The mounting bracket for the 075. Slowly tighting the screws in a crisscross pattern. Are the mounting plates threaded or smooth bore no threads

Threaded.

Val

01-05-2006, 09:25 PM

I would try walnut veneer on the sides rather than paint, and JBL Blue on the front. Applying veneer, especially paper-backed veneer, is not especially difficult and really pays off.

Is paper backed veneer attached with contact cement like regular veneer? Can you recommned a source?

Thanks for your comments.

Val

01-05-2006, 09:31 PM

here's what I meant by 0-ring (not associated w/ seller)... white in this picture:

Thanks for the picture. My 075's don't have the integral mounting flange. They have a separate bracket that that the 075 slips into. The bracket has a gap that won't press on the o-ring.

jbl4ever

01-05-2006, 09:53 PM

Threaded.Val, can you drill the 4 mounting holes for the 075 on the baffle. This will tighten the mounting bracket better. You may be able to put the gasket on the front of the bracket. You do have the clamping bolt on the side of the bracket. Can not tell

Val

01-05-2006, 10:04 PM

Val, can you drill the 4 mounting holes for the 075 on the baffle. This will tighten the mounting bracket better. You may be able to put the gasket on the front of the bracket. You do have the clamping bolt on the side of the bracket. Can not tell

Yes. Right now the bracket is attached with 5 Spax screws into the MDF. It seems solid now. Is the worry that, over time it will loosen?

Here's pic of the driver and it's bracket. Perhaps the o-ring will solve my whistle problem even with the small gap.

Thanks

jbl4ever

01-05-2006, 10:10 PM

Val, are the 3 holes threaded.

John W

01-06-2006, 08:31 AM

Is paper backed veneer attached with contact cement like regular veneer? Can you recommned a source?

Here is a thread detailing some L112s I put veneer on.
http://audioheritage.org/vbulletin/showthread.php?t=6884

I use the water-based contact cement for paper backed veneer. A good source for the veneer is http://www.oakwoodveneer.com (http://www.oakwoodveneer.com/)

Val

01-06-2006, 02:19 PM

Val, are the 3 holes threaded.

Nope.

Val

01-06-2006, 02:36 PM

Here is a thread detailing some L112s I put veneer on.
http://audioheritage.org/vbulletin/showthread.php?t=6884

I use the water-based contact cement for paper backed veneer. A good source for the veneer is http://www.oakwoodveneer.com

Great thread reference. Thanks. Those look beautiful. I might just try that.

scorpio

01-28-2006, 02:38 PM

Hey Val,

Now that you had these playing for a while, how do you feel about them? Specailly, how do you feel about bass extension?

I have a 2-ways system with LE 15A using JBL 1975 enclosure timensions; they are somewhat larger (over 5 cuft internal), but would like to build a nex pair with better finish, I was wondering how yours are faring,

Thanks

Val

03-18-2006, 08:44 PM

Now that you had these playing for a while, how do you feel about them? Specailly, how do you feel about bass extension?

Thanks

I've be hecka busy (new boss) and out of the loop for a bit, so sorry for the delay...

I'm almost done with the first of two cabinets. Today I finally tacked in the fiberglass insulation. The one cabinet sounds pretty good. The bass extension is not great, but the bass is very nice to my ears. I've become so accustomed to the sub-woofer band pass type bass that I'd forgotten how smooth bass can be.

Val

03-18-2006, 09:01 PM

Val

03-18-2006, 09:15 PM

Here's how slow I am moving! Radiused the corners, added rubber feet, thru bolted the 075. Just need to build the grill. I plan to only cover the LE15 with a grill and let the world see the 075 and 375. My WAF has an excellent coefficient of acceptance! One day, if I'm lucky, I'll lay my hands on a pair of acoutic lenses.

Zilch

03-18-2006, 10:24 PM

I really have no idea what to do to tune my box. At the moment I have two 3" ports, each 9 1/2" long. I think I've found the resonant frequency. I stepped thru the low frequencies, feeling the LE15 surround at each, looking for relative stillness. At 27Hz, the cone is the stillest. So I'm guessing that's the resonant frequency. I'm not sure what freq to tune to. Is 27 Hz as good as any?27 Hz is probably too low. Looking back in the thread, we found 5.75" for 32 Hz, 7.00" for 30 Hz. Gordon suggested a little longer for each.

BB6P confirms you are indeed tuned to 27.02 Hz with your two 9.5" ducts. You've run out of cone displacement with that tuning, however; you're only good for about 60 Watts in the 40 - 60 Hz range.

Either the 30 or 32 Hz tuning will get you 1.5 times that in power handling. Try them both, maybe, in your desired room location. See which sounds best to you....

Val

03-19-2006, 12:09 AM

27 Hz is probably too low. Looking back in the thread, we found 5.75" for 32 Hz, 7.00" for 30 Hz. Gordon suggested a little longer for each.

BB6P confirms you are indeed tuned to 27.02 Hz with your two 9.5" ducts. You've run out of cone displacement with that tuning, however; you're only good for about 60 Watts in the 40 - 60 Hz range.

Either the 30 or 32 Hz tuning will get you 1.5 times that in power handling. Try them both, maybe, in your desired room location. See which sounds best to you....

Thank you Zilch. Just what I needed to hear. I'll trim the ports down.

John

03-19-2006, 11:32 AM

Hi Val :) If you only plan on covering the 15" why not use a waffle grill???

Val

03-19-2006, 12:51 PM

Hi Val :) If you only plan on covering the 15" why not use a waffle grill???

Something like this?

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-375

toddalin

03-19-2006, 01:17 PM

Something like this?

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-375

:blink:

Maybe for a car or a PA, but for the home...:barf:

Val

03-19-2006, 02:00 PM

5.75" for 32 Hz, 7.00" for 30 Hz.

Just cut 3" off of both ports, for 6.5". I'm measuring about 31Hz now.

Thanks.

g

Val

03-19-2006, 02:03 PM

:blink:

Maybe for a car or a PA, but for the home...:barf:

Yep, agreed.

John

03-19-2006, 05:53 PM

Well I will bet your last donut that when someone's foot accidently goes thru the cone you will be thinking about waffles?:p

Val

03-25-2006, 08:34 AM

Mmmm waffles...

As I'm listening to my rig I'm realizing that the 375 is dominating. I can't seem to get enuf attenuation using the controls on the LX5 and N7000. Is it as simple as putting an L-Pad between the N7000 and 375?

Thanks...

Val

07-11-2006, 12:07 AM

It's been over a year and I finally got these guys finished and in the living room. Thought I'd share some pics. I could not have done these without the help of this forum!!! :applaud:

Val

07-11-2006, 12:12 AM

Still working on tuning them...

Val

07-11-2006, 12:14 AM

The 375 dominates...l-pads should be here tomorrow

Val

07-11-2006, 12:17 AM

Applied Kilz primer and Rust-Oleum flat black with a brush.

Val

07-11-2006, 12:21 AM

I've only got 1" of fiber glass inside. Trying to determine if I want to add another layer...

yggdrasil

07-11-2006, 03:51 AM

Very nice.:applaud:

These babies should give you lots of great listening.

johnaec

07-11-2006, 06:08 AM

Nice! How do they sound?

John

Val

07-11-2006, 07:28 AM

They love to play slow jazz. Stand up bass, piano, and any type of percussion sound fabulous. They have smooth wide bass (non-sub-woofery) that I am enjoying. The highs are crisp, upper mids are nice but over powered (L-Pad should come today!). The lower mids are a bit muddy. I'm interested to see if that cleans up a bit when I turn down the 375. Cranking rock will drive you from the room, again, the 375. That thing is a monster. 4" voice coil, a magnet to choke a horse and a phase plug (not exactly sure what it is but is sounds so cool) make the 375 very forceful. This is my first vintage JBL rig and I'm amazed by the effortlessness that these speakers produce sound. Wow.

The hardwood floors start to resonate a bit with the bass when you crank them up. Not a lot I can do about that. A friend did suggest mounting them on concrete pillars anchored in bedrock but I'm not quite there yet:). I think that they might have a secondary bass frequency that they resonate at that I need to sweep out. At some point I might rent an audio spectrum analyzer. Right now I'm doing all tuning by ear and feel. Advice is welcome!

I'm pushing them with a cheapo Sony 5.1 reciever rated at 100w per channel. I put it in 2 channel mode.

I've got to say again how I couldn't have come close to the design and quality without this forum. I'm very happy with the speakers and this forum.

Robh3606

07-13-2006, 07:24 AM

Hello Val

Those look great!! I like the finish on them. I would get them up a bit off the floor. That should help decouple them.

Rob:)

Val

11-27-2013, 11:18 PM

So I've now been listening to these speakers for about 6 years and I still love them, but, I know their limitations too. The most bothersome to me is the lack of mid-bass. Today I was reading up on Paragons as they use the same driver set (LE15a/375/075) and saw a note that they sound better with the LE15a/375 crossover bumped up from 500hz to 800hz. Then the light went on, why not try running the LE15a full range like the 2213 in my 4312? Tonight I rewired them and it is a huge improvement! Even my dog noticed the difference. I plan to run them like this for a bit. This certainly reawakens my desire for tri-amping them (I've been using the Lx-5 500hz and N7000 7000 Hz crossovers that came with the driver set).

My other obsession of late is building a 2973 smith horn for the 375. I've read all I can on this site on the topic and is seems this would be a jump up from the H93 horn/L91 lens.

Any other thoughts on how get the best sound from the LE15a/375/075 driver set?

Mostlydiy

11-28-2013, 12:45 AM

Any other thoughts on how get the best sound from the LE15a/375/075 driver set?

Besides building a paragon cabinet? :)

/Mostly

Val

11-28-2013, 03:26 PM

Besides building a paragon cabinet? :)

/Mostly

I should have seen that coming but I did say I wanted them to sound better. :D

Mostlydiy

11-29-2013, 03:03 AM

I think you are spot on by changing that horn. If you want to stay vintage the 2397 would be better by a large marigin I believe. If you got hold on a pair you could just place them on top and go active all the way.

Its kind of funny because I have considered building a system very similar to yours. The only difference beeing a D130 in between the Le15a and the 2397. If the cross over is successful I think that would be the ultimate JBL vintage system, utilizing the most popular and renown JBL drivers :)

/Mostly

Val

11-30-2013, 05:32 PM

Its kind of funny because I have considered building a system very similar to yours. The only difference being a D130 in between the Le15a and the 2397.

/Mostly

Interesting. Just to be clear, you would create a 4-way of LE15a/D130/375/075? If so, what crossover frequencies would you start with?

Mostlydiy

12-01-2013, 04:59 AM

Interesting. Just to be clear, you would create a 4-way of LE15a/D130/375/075? If so, what crossover frequencies would you start with?

Yes, thats my intentions. I have approximately 1245,5 projects on my to do list and Im not sure just where in the list this project is hiding. I know it wont be started tomorrow, thats for sure. I havent thought much about the xo but I would probably start with an active system to go trial and error with different xo points and slopes. Right of the bat I think i would start with 80,800,5000 12db or something like that.

/Mostly

donsof

12-04-2013, 03:49 PM

Val

12-04-2013, 11:08 PM

Val
This was a very good read. I recently found some of your JBL components, and was trying to put something similar together.
were your drivers all 16 Ohm?
Is the 7000 and LX5 also rated for 16 Ohm loads?

How does one know if a crossover / divider network is 8 or 16 Ohm when found in the wild, with no knowledge of the origin?

I posted a thread today on the crossover section about my issues.

thanks for any help... this place is fun to stop and read! Don

Hi Don - I'm glad you enjoyed this rather long post. I have really enjoyed this project and being a part of this community. I consider this project a work in progress and am currently thinking about tri-amping and a smith horn for the 375.

My drivers are all 8 ohm. I don't think 8 vs. 16 ohm will make much of a difference on the crossover but there are many on the this forum that will know better than I do.

I LOVE the tone of the LE 15A. It's limitation, in my opinion, is that it doesn't have a very wide range. If you are doing Home theater or playing music mastered in the last decade, you will want to augment with a sub (a 2245h in my case:)). It also doesn't reach up very high. It's spec sheet says to cross it over above 600hz (though elsewhere JBL suggests a 800hz crossover is fine). As I mentioned above, I am running my full range for fun and loving it. I'm telling you, even with my sub turned off, there are times where I simply adore the tone of this driver! It sounds like yours is re-coned to a 2235 which JBL recommends crossing over at 1000hz.

I see from your other post that you have an LE-85. I don't have experience with this driver but I will say this; the simple cast metal horn in your other post can certainly be improved upon. Read up on this for a better approach: http://www.audioheritage.org/vbulletin/showthread.php?5454-1200Hz-Smith-horns-for-1-quot-driver/page4

Val

Val

06-15-2014, 03:57 PM

I have been wanting to tri-amp these speakers for a long time but have never been able to scrape together enough mad-money to buy 6 channels of amplification and an active crossover. A few weeks ago I picked up a non-operational Marantz SR7400 AVR at a garage sale for $20 including 5 working ProCinema speakers. I was able to repair the AVR and I noticed that it had something called 7.1 Mode which accepts output of an external 7.1 multichannel decoder. After looking at the manual and doing a few tests I now realize that when in 7.1 mode I basically have 7 channels of 105 watt/ 0.08% THD amplification into 8 ohms. Once a volume level is set in 7.1 mode, the AVR "remembers" the volume and mode even after the AVR is unplugged for several hours. So my thought would be to run this in 7.1 mode and plug it into switched power.

Now I'm trying to think of what can go wrong with using the AVR as my 6 channels for tri-amplification. Clearly, if the AVR gets flipped to any non-7.1 mode where signal is present, my tweeter and mid-range could blow. I'm thinking that I need to install shorting RCA plugs in all inputs and short across both FM antenna inputs. That way, if somehow if gets into a non-7.1 mode it will not have any signal to amplify and blow my speakers. What else could go wrong?

As for an active crossover, I'm thinking of an Ashly XR4001 - 4 way stereo active crossover. I like the XR4001 as I have the option of running my sub in addition to the LE15A/375/075, and one pair of channels can go beyond the 8kHz limit of the other models (it goes to 24kHz:blink:). The down side it that these are no longer in production and so I will need to buy a used one. My backup plan would be two XR1001s. Thoughts?

Val

02-10-2015, 11:39 PM

I have been wanting to tri-amp these speakers for a long time but ...
...life happened...Father, I have sinned, my last post was 8 months ago...

I've collected my active crossover (Ashly XR-4001) and amps (JBL 6320 for the LE15A and Emotiva UPA-500 for the 375 and 075). I'm building cables and a guard to keep busy fingers off of knobs. I've put together a diagram because I'm stuck in a hotel room on a business trip. As always, open to input...

Mr. Widget

02-11-2015, 08:04 AM

A couple of thoughts...

That's not a lot of power on the LE15As, but if you aren't into loud, that won't be s problem. What horn do you have for the 375s? Even though vintage JBLs frequently used this frequency, very few horns will pull this off if you don't want the squawky-honky sort of midrange common to vintage systems.

Widget

grumpy

02-11-2015, 08:17 AM

Val

02-11-2015, 09:13 PM

That's not a lot of power on the LE15As, but if you aren't into loud, that won't be s problem.

You have a point with the 6230 as it's only rated at 75watts. I got is for a song and may end up swapping it out.

What horn do you have for the 375s? Even though vintage JBLs frequently used this frequency, very few horns will pull this off if you don't want the squawky-honky sort of midrange common to vintage systems.

I'm pretty sure my components were bought in the mid-1970's as a S8 Component Series so the horns are HL93's and the slant plate diffusers are L91's. I totally have the squawky-honky issue you mention. Once I have the tri-amping in place I plan to move up the crossover as much as the LE15A will go...which sadly is likely not very much. Would replacing the HL93 with a smith horn help with the squawky-honky issue?

Val

02-11-2015, 09:19 PM

I'd be tempted to also try it the other way... don't use the lowest filter band
unless you bring in subs, leaving the tweeter high end unfiltered and using
the 'response' knob to get into the 40's as much as possible. Not a huge
effort to try it both ways and your personal preference and listening may
nudge you back to your original idea. Just a thought.

May be possible to modify the unit's lowest crossover range to use a "divide by 20"
rather than by 10 (20-400Hz), but that would require a schematic and some EE know-how.
Seems like someone here may have done that on this or a similar unit. :dont-know:

I've wanted to do just as you say as the highest band let's you crossover up to 24k. There is a bit of harshness in the 075 that I would like to address. The other bands max at 8k. I had not thought about a hardware hack. With the stock XR-4001 if I use the upper bands then I would be rolling off the LE15A at 40 hz. I do have my 2245H sub down there though.

Mr. Widget

02-12-2015, 12:32 AM

I totally have the squawky-honky issue you mention. Once I have the tri-amping in place I plan to move up the crossover as much as the LE15A will go...which sadly is likely not very much. Would replacing the HL93 with a smith horn help with the squawky-honky issue?You can go to 800Hz and use the JBL 2397 horns and you will hear a marked improvement. Be aware of the fact that the 2397 has a very wide horizontal pattern so side reflections should be controlled for the best performance.

As to Grumpy's suggestion... if you plan on going with your 2245 sub then a 40-80Hz crossover between the LE15As and sub should be fine.

Widget

BTW: I see you are in Palo Alto... if you want to borrow a pair of 2397s, mine are not currently in use.

ivica

02-12-2015, 02:01 AM

You have a point with the 6230 as it's only rated at 75watts. I got is for a song and may end up swapping it out.

I'm pretty sure my components were bought in the mid-1970's as a S8 Component Series so the horns are HL93's and the slant plate diffusers are L91's. I totally have the squawky-honky issue you mention. Once I have the tri-amping in place I plan to move up the crossover as much as the LE15A will go...which sadly is likely not very much. Would replacing the HL93 with a smith horn help with the squawky-honky issue?

Hi Val,

I have 2231A & 2441&(with Radian 1245-16) & 2311 & 2308 and 2405 what would be almost equivalent with
136A + 375 + HL93 with "slat plate diffusers" +077 (075), using cut-off frequencies about 800Hz, and 8kHz sounding quite acceptable.
It seems to me that bass section has to be stopped about 600~700Hz, while VHF section has to start from about 800~1000 Hz.
Owing to the relatively short horn ( about 11cm) and internal-driver horn (about 7cm) honky effect is not so 'pronounced', or better to say much, much less then on 2312/2307&2420 combo.

regards
ivica

Val

02-15-2015, 04:37 PM

You can go to 800Hz and use the JBL 2397 horns and you will hear a marked improvement. Be aware of the fact that the 2397 has a very wide horizontal pattern so side reflections should be controlled for the best performance.

As to Grumpy's suggestion... if you plan on going with your 2245 sub then a 40-80Hz crossover between the LE15As and sub should be fine.

Widget

BTW: I see you are in Palo Alto... if you want to borrow a pair of 2397s, mine are not currently in use.

So cool that the 2397's can improve my situation. I would love to borrow your 2397's when the time comes, very generous, thanks.

Val

02-15-2015, 04:51 PM

Hi Val,

I have 2231A & 2441&(with Radian 1245-16) & 2311 & 2308 and 2405 what would be almost equivalent with
136A + 375 + HL93 with "slat plate diffusers" +077 (075), using cut-off frequencies about 800Hz, and 8kHz sounding quite acceptable.
It seems to me that bass section has to be stopped about 600~700Hz, while VHF section has to start from about 800~1000 Hz.
Owing to the relatively short horn ( about 11cm) and internal-driver horn (about 7cm) honky effect is not so 'pronounced', or better to say much, much less then on 2312/2307&2420 combo.

regards
ivica

You are right, there are similarities between our component sets with a few notable differences. I think the 2231A rolls off around 2k and the LE15A under 1 kHz and the 2405 is a much better tweeter than the 075. I like my old LE15A's and 075's but the 2231 and 2405's are better drivers.

Val

03-01-2015, 07:50 PM

Forgive me if this is off topic, but, I fear sticky fingers turning knobs. So, I decided to make a locking cover for the bottom portion of my DIY equipment rack. I bought some "Union Jack" design decorative metal from Amazon and a skeleton key lock (the family is very excited to have a skeleton key lock in the house). I knocked together a frame and now can lock my tri-amp gear.

Next up on tri-amping...finish making cables!

64766647656476464767

grumpy

03-02-2015, 10:45 AM

Looks nice. Prudent idea :)

Val

03-30-2015, 08:24 PM

The slowest tri-amp project continues.

Awhile back I bought a Smart Strip to control the power for my crossover and amps. The idea is that is senses power draw on the control plug (I plugged in my AVR) and it turns on the amps and such. Turn on the AVR, all the amps go on. Great idea. Even has a sensitivity control. I could only get it to work some of the time. So it falls into the "don't waste your money" category.

I ended up buying a solid state relay and some parts and made my own 12v triggered power. One plug is always hot, one is triggered by my AVR's 12v. Now it works every time. The SSR was only 12 bucks for 25A. Came with a big heat sink. Who doesn't like heat sinks? Anyway, it was a fun sub-project. About $25 in parts. You can't see it in the pics but there is a 3.5mm plug for the 12v trigger input just under the power cable.

ivica

03-31-2015, 12:00 AM

Val

03-31-2015, 09:29 AM

Hi Val,

Why not to use standard (electro-mechanical) relays, that can be controlled by 12V or 24V or.... supply.

regards
ivica

I actually started with looking at those and they would work fine. The SSR was only $12, is silent and didn't require a cap for emf suppression.

1audiohack

03-31-2015, 10:46 AM

I actually started with looking at those and they would work fine. The SSR was only $12, is silent and didn't require a cap for emf suppression.

+1. Magic. :)

Val

10-30-2016, 05:24 PM

I've finally been able to carve out the time to work on these speakers. I have just replaced my 075s with a very nice pair of 077s (before and after pictures below). No cabinet mod's required. They sound noticeably better. Breathier and a certain harshness is gone.

Before
74310

After
74311

I'm also getting ready to try-amp these (really quad-amp as the 2245H based sub-will be in the mix as well). They were quad-amped before with an Ashly 4001, but it died and I was able to get a few buck on eBay for it. It's being replaced with a MiniDSP 4x10HD that should arrive coming Wednesday. I've already downloaded the configuration software which allows me to start configuring them even without the box being connected. The MiniDSP has two analog inputs and 8 outputs. Each input and output has 5 paramedic eq's available which I will configure another day when I have some help with measurement equipment. Today I played around with estimating the acoustic centers of each driver using only the crudest of tools (ruler) and configuring the delays. These will serve as a starting point and hope to later set them using actual measurements. I've also laid in the crossover frequencies. Going with LR 24db/octave.

Output Screen Shot
74312
Channel 2 Crossover Screen Shot
74313