L7 Breakup

[John W]

Hi everyone.
I recently got a good deal on a pair of L7s. The drivers are all in fine shape and functioning great, unfortunately the cabinets and grills are a little messed up. They are repairable, but even so, my room wouldn’t be ideal for the speakers. Placement would be a problem. My wife thinks they are ugly as sin too.
I am considering a separation… of the drivers.

What I am thinking is placing the top 3 drivers into their own bookshelf cabinet, keeping the same time-aligned angle and baffle size, and putting the LE120H drivers into a separate pair of subwoofer cabinets like the Synthesis S3S.

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/S3S%20quick%20specs.pdf

I figure it would be easier to align the woofers to the room if they were separated somewhat from the rest of the drivers.

Good idea or waste of time and speaker?

The current L7 configuration has the LE120H crossing in at 180hz. Is that too high for what I am considering?

[Earl K]

Good idea or waste of time and speaker?

- I think it's a good idea to make something that you and the family will like to keep around.

- Look to the L3 for inspiration ( you'll just end up with a L3 plus midrange ) . That model runs full range using the same 8 inch woofer ( obviously , its' cabinet is tuned lower ) .


The current L7 configuration has the LE120H crossing in at 180hz. Is that too high for what I am considering?

- Yes, IME, you want to build a speaker enclosure that does nicely on its' own, down to @ 70 hz .

:)

[John W]

Finished the first half of the L7 breakup.

The top section with the 035TiA, 704g, 708g and slightly modified NL7 crossover have been put in there own boxes. The boxes are roughly 1 ft3 tuned to 35hz. The width, baffle layout and angle are the same as the original L7s, 9.1/2 in. Otherwise they are 22 3/8 tall 10 3/8 deep on top, 13 5/8 deep on the bottom. There is a 5.25 x 2” vent out the back.

The veneer is a nice quarter sawn cheery with cheery corners that have a slightly larger radius than the original. They are pretty light right now, but should darken up a fair bit in the next year or so.

[John W]

The L7 has two separate crossover boards, which works out great. I modified the upper section by removing the 90uf capacitor on the 708g input and replacing it with a solid wire link. This basically removes the 180 Hz high pass on the woofers and lets them run as low as they’ll go.

Here’s a picture of the modified crossover, a plot of the response, and a picture of the speakers on the shelves in the living room that were the reason for the modification.

[John W]

They sound great as is. Even without the subwoofer, they have a nice low-end.

Next step is a pair of LE120H subwoofers. I haven’t been able to trace down the actual TS parameters for these drivers. Does anyone have these? From searching around the forum it looks like a good alignment is 3 ft3 tuned to 30Hz which appears to be the approximate size of Synthesis subwoofer.

[Robh3606]

Very nice John. Not surprised on the low end with the 8's I have L3 and they are nice 2 ways.

Rob:)

[sourceoneaudio]

L@@@ks very good John. Nice touch on the rear panel, looks factory.


Jeff
J/S-S1A :D

[4313B]

I always look forward to your posts John!

Outstanding as always. :)

[DavidF]

"... here's a picture of the modified crossover, a plot of the response, and a picture of the speakers on the shelves in the living room that were the reason for the modification.

John, where did you have the enclosures when you ran the plot? Curious if they were on the stands out from a boundary.

The beading around the trim pieces is a very nice touch.

DavidF

[John W]

John, where did you have the enclosures when you ran the plot? Curious if they were on the stands out from a boundary.

The beading around the trim pieces is a very nice touch.

DavidF

The enclosure was on the edge of a low table, sort of in the middle of the room. The 200Hz dip is likely due to boundary issues.
For curiosity, I tried measuring on the shelf, but I couldn't adjust the mic to reach high enough. The whole setup is not the pinnacle of accuracy, but gives a pretty good idea on how they behave within the room.

[Titanium Dome]

Good looking, indeed.

The LE120H-1 was used as a sub driver in the Citation 5.4 and in the Fosgate Audionics CSS220 THX sub. I have three of the latter, but they're buried in the dungeon, and my back's out of sorts.

Maybe I can dig one out tomorrow and give you a volume estimate.

[Zilch]

http://audioheritage.org/vbulletin/showpost.php?p=44535&postcount=7

[Titanium Dome]

http://audioheritage.org/vbulletin/showpost.php?p=44535&postcount=7

Ah, well, there it is. Thanks, Zilch (and Giskard). Now I can continue to rest my back.

[Zilch]

Now I can continue to rest my back.Not so FAST, Advil breath.

Well still need the port dimensions, and the Fosgate volume may be different from the other two.... :yes:

[Titanium Dome]

Oh, all right.

..and it's Flexeril breath to you, Mr. Flexeril breath. ;)

I'll be back in a minute.

[Titanium Dome]

This should be everything you need to get a volume. Looks to be just above 3 cu. ft.

[John W]

Thanks,
That about covers it.

[John W]

Finished the bass bins this weekend.
I tossed around few different layouts including the S3S and the nice sketch by titanium dome. Eventually I went with the stock box size recommended by JBL for the 128h in the enclosure guide.

http://www.jblpro.com/pub/manuals/enclgde.pdf. 2.5 ft3 tuned to 30hz.
The main factors in this choice were that I wanted them a little taller than a cube type subwoofer, and I had a 4x4 square of veneer left from the top boxes. This shape allowed veneer on 3 sides.
Anyway, they sound great. The setup in the picture has them bi-amped at 100hz which works fine.

[Titanium Dome]

John, that looks really nice. I'm glad you were able to do this. You may be the first person since the original design team to hear these drivers all facing frontward.

You were able to accomplish one of the main design goals, which was a narrow baffle for the top three drivers. Well done.

[Earl K]

- This new L7 ( plus ) setup is absolutely stunning .

- John, I've always loved that yellow & blue patterned rug ( & the fireplace ) .
- They always brings out the best in your new projects. ;)

<> Cheers

[4313B]

Outstanding! :yes:

[macaroonie]

They are too near your Jotul stove, all your great work will come undone in the winter.:p

[John W]

- This new L7 ( plus ) setup is absolutely stunning .

- John, I've always loved that yellow & blue patterned rug ( & the fireplace ) .
- They always brings out the best in your new projects. ;)

<> Cheers
Thanks for the kind words. I'm enjoying the setup, and my wife appreciates the compliment on the rug. :)
The location is only temporary. I'm still waiting for the dedicated media room.

[kingjames]

Beautiful work.

[ka7niq]

Hi everyone.
I recently got a good deal on a pair of L7s. The drivers are all in fine shape and functioning great, unfortunately the cabinets and grills are a little messed up. They are repairable, but even so, my room wouldn’t be ideal for the speakers. Placement would be a problem. My wife thinks they are ugly as sin too.
I am considering a separation… of the drivers.

What I am thinking is placing the top 3 drivers into their own bookshelf cabinet, keeping the same time-aligned angle and baffle size, and putting the LE120H drivers into a separate pair of subwoofer cabinets like the Synthesis S3S.

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/S3S%20quick%20specs.pdf

I figure it would be easier to align the woofers to the room if they were separated somewhat from the rest of the drivers.

Good idea or waste of time and speaker?

The current L7 configuration has the LE120H crossing in at 180hz. Is that too high for what I am considering?
I have some L7's I have had for about a month now.
The low frequency crossover at 180 hz is an interesting choice by JBL.

IMHO, they "get away" with it in the L7 design by side firing the woofers.
This makes the inevetible cabinet vibration fire to the sides, instead of right at you.
A quick and dirty way of doing it as opposed to my B&W 801's.
The 801's have a relatively high 300 hz crossover.
So, to control coloration in this all important region, B&W went to heroic measures and designed the Matrix Cabinet.

The relatively high crossover to the 8 inch driver in the L7 is what gives it it's ability to play LOUD w/o distortion.
This it does real well.

Your ultimate choice of woofer to 8 inch lower midrange crossover points will ultimately be determined by your room, and how well you have controlled coloration in your lower woofer boxes.

IF it were me, I would consider an adjustable electronic crossover, and a big solid state amp on the woofers, and your tube amp up top on the rest.

This will pay enoromous dividends in sound quality.

BYW, in a steep slope passive crossover w/o time delay compensation, driver voice coil alignment is critical.
I see you paid attention to it.

I used to live in Seattle, up in the North End.
My friends own Definitive Audio in the U District on Roosevelt Way.

Haven't been back to Seattle since 1989.
I miss it, but my friends up there say it has turned into LA, with trees.

The L7 has proved to be an "interesting speaker" for me.
I must have had a bad pair initially, because they sounded truly awful.

This pair I have hadn't been played for almost 4 years!

Initially, they sounded wonderful.
I was quite excited
But, they changed, perhaps the caps had to re form from 4 years of non use ?
My opinion of them is still very good, but not quite as good as what I heard initially.
One thing is for sure, they like a big, high current amp, at least in my big room.

My 50 lb JVC RX DP 9 receiver gets the life sucked right out of it.
My Luxman M 117 amp sounds good, but is a little too mellow for these speakers, and my Adcom 585 isn't right either.
My Moscode 600 will be back shortly, and I plan to try some other amps on them too that I own.
Got to get them bi wired too.

My pair are MINT, got lucky!
You could literally eat off of mine.

Nice Job you did :applaud:

[JBLnsince1959]

that's really one beautiful job..congrads:applaud:

[hjames]

Finished the bass bins this weekend.
I tossed around few different layouts including the S3S and the nice sketch by titanium dome. Eventually I went with the stock box size recommended by JBL for the 128h in the enclosure guide.

http://www.jblpro.com/pub/manuals/enclgde.pdf.
Anyway, they sound great. The setup in the picture has them bi-amped at 100hz which works fine.

Thats a pretty set of speakers - very neat work - kudos to you for that idea and the design!

[89-300ce]

This is probably obvious to most, but, how did you get that transition line/joint from the corner pieces to the sides and baffle. It really set them off.

Jorg

[John W]

This is probably obvious to most, but, how did you get that transition line/joint from the corner pieces to the sides and baffle. It really set them off.

Jorg
Thanks,
The front edges of the boxes are solid wood, cherry in this instance, which is needed to round over the baffle edges. I figured I would have a hard time matching color and grain pattern between the solid wood and the veneer, so decided to add a thin walnut band between the two. The darker the better in case the glue joints don't mate perfectly. Basically the banding is 1/8in walnut strips glued to the edging before it is applied.

[89-300ce]

Beautiful!

Is the banding recessed a bit?

Jorg

[John W]

Beautiful!

Is the banding recessed a bit?

Jorg

Nope, it is flush.
A few of the jbl boxes have a recessed kerf around the edges, probably for the same reasons. Here is an example from a 120Ti

[Russellc]

All I can say is WOW! I sure wish I could build cabs half that nice! If the wife doesnt like those, you may as well get a new hobby. Outstanding!:cheers::applaud:

Russellc

[mike]

Impressive, well thought out and very tastefully done in my opinion. Even though it's a unique design the overall look is very "upperend JBL-ish" to me at least.

Is that a home made 6550 based amp in the picture?

Mike

[ken.pugmire]

My L7's are loaded in the car as we speak. Im building new cabinets as well. Not quite sure on the design direction yet...however I want to use aluminum/zinc alloy for the enclosure.