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Author Topic: Lab Horn - Brad Litz's Design and Honresp data  (Read 659 times)

Erik Genthe

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Lab Horn - Brad Litz's Design and Honresp data
« on: November 20, 2017, 07:24:40 am »

Hi,
this Winter i would like to build a Labhorn. I've got the Eminence Speakers already.

I have found some hornresp data via Google Images (i dont know exactly where i got them from).
The simulation showed a 3,5dB dip at 45hz. So i started experimenting and end up in decr. Throatchamber (Frontchamber?) volume by 10liters and increasing rearchamber volume  by 10 Liters. You can probably archieve this by moving the Driver a bit towards hornthroat... Horn flare would change as well.
After I did this, i found out, that Brian Litz has already done this (Labhorn v3), and that this type of Labhorn has already been built.

Sadly every link to building plans that i have found is down.
Could someone help me getting theese plans please?

I guess theese plans: https://www.prosoundweb.com/channels/live-sound/lsp_documentation_page_drawings_photos_specs_and_more/, don't include Brian Litz improvements.
The measurement (https://www.prosoundweb.com/lsp/response1.gif) shows the same Dip at 45hz.

2nd Question:
Is there Hornresponse input Data for the plans shown on the Documentation page?
Is there Hornresponse input Data for the plans of Brian Litz?
If not, of course i will create the Data by myself and post it here.


Of course i will post Measurements of the finished Horn afterwards. :)

Btw: I archieved some nice Result's in (at least in frequency response) using Passive Radiators. Probably someone with more Knowledge could take a look at theese. (Hornresp records are attached)

Best regards
Erik Genthe
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Tim McCulloch

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Re: Lab Horn - Brad Litz's Design and Honresp data
« Reply #1 on: November 20, 2017, 07:47:15 pm »

Hi,
this Winter i would like to build a Labhorn. I've got the Eminence Speakers already.

I have found some hornresp data via Google Images (i dont know exactly where i got them from).
The simulation showed a 3,5dB dip at 45hz. So i started experimenting and end up in decr. Throatchamber (Frontchamber?) volume by 10liters and increasing rearchamber volume  by 10 Liters. You can probably archieve this by moving the Driver a bit towards hornthroat... Horn flare would change as well.
After I did this, i found out, that Brian Litz has already done this (Labhorn v3), and that this type of Labhorn has already been built.

Sadly every link to building plans that i have found is down.
Could someone help me getting theese plans please?

I guess theese plans: https://www.prosoundweb.com/channels/live-sound/lsp_documentation_page_drawings_photos_specs_and_more/, don't include Brian Litz improvements.
The measurement (https://www.prosoundweb.com/lsp/response1.gif) shows the same Dip at 45hz.

2nd Question:
Is there Hornresponse input Data for the plans shown on the Documentation page?
Is there Hornresponse input Data for the plans of Brian Litz?
If not, of course i will create the Data by myself and post it here.


Of course i will post Measurements of the finished Horn afterwards. :)

Btw: I archieved some nice Result's in (at least in frequency response) using Passive Radiators. Probably someone with more Knowledge could take a look at theese. (Hornresp records are attached)

Best regards
Erik Genthe

The back story behind the LABhorn is that Tom Danley designed it in response to the price/output/SQ of an expensive horn sub from a T.L.A. company.  The original was intended to be used in multiples so Tom D used the same criteria.  It was his gift to those who'd trade sweat equity and sawdust to receive significant monetary savings.  Also interesting is that Tom designed this solely in simulation and never built a physical unit.

The response evens out as you add more LABhorns together - 4 was the target quantity to get smoothest response.  You can play with the design if you like but I'd suggest building a pair (or more) for each side.  By the time Brian got involved I'd mostly stopped following the topic so I can't comment on his modifications.

I heard 1 LABhorn at Paul Bell's Jan 2007 NYC sub shootout (there is a thread about this in the LAB forum archives) and that unit had a couple of changes but in auditioning it we were kind of surprised that the "FrankenLAB" was still a pretty good sub (it was shorter and lacked the woofer cover plates) and held up pretty well until compared to the top subs in the shootout.

Have fun, good luck.

Tim Mc
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Mark Wilkinson

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Re: Lab Horn - Brad Litz's Design and Honresp data
« Reply #2 on: November 21, 2017, 08:48:41 am »

Hi,
this Winter i would like to build a Labhorn. I've got the Eminence Speakers already.

I have found some hornresp data via Google Images (i dont know exactly where i got them from).
The simulation showed a 3,5dB dip at 45hz. So i started experimenting and end up in decr. Throatchamber (Frontchamber?) volume by 10liters and increasing rearchamber volume  by 10 Liters. You can probably archieve this by moving the Driver a bit towards hornthroat... Horn flare would change as well.
After I did this, i found out, that Brian Litz has already done this (Labhorn v3), and that this type of Labhorn has already been built.

Sadly every link to building plans that i have found is down.
Could someone help me getting theese plans please?

I guess theese plans: https://www.prosoundweb.com/channels/live-sound/lsp_documentation_page_drawings_photos_specs_and_more/, don't include Brian Litz improvements.
The measurement (https://www.prosoundweb.com/lsp/response1.gif) shows the same Dip at 45hz.

2nd Question:
Is there Hornresponse input Data for the plans shown on the Documentation page?
Is there Hornresponse input Data for the plans of Brian Litz?
If not, of course i will create the Data by myself and post it here.


Of course i will post Measurements of the finished Horn afterwards. :)

Btw: I archieved some nice Result's in (at least in frequency response) using Passive Radiators. Probably someone with more Knowledge could take a look at theese. (Hornresp records are attached)

Best regards
Erik Genthe

Can't help you find your actual link requests.  But I do remember Brad Litz and Peter Sylvester's modification efforts. In case you haven't seen this thread that delves into such mods, you probably want to...
http://www.diyaudio.com/forums/subwoofers/171294-fixing-labhorn.html

My take from having built 4 off the original plans, is those plans are fine unless you're wanting to only use 1 or 2 together....then I'd probably work on smoothing.
That said, I've found 2 labs together to measure as smooth as other horn subs that nobody ever talks about needing smoothing...so it's kinda just a matter of how important is it to you...
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John Chiara

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Re: Lab Horn - Brad Litz's Design and Honresp data
« Reply #3 on: November 21, 2017, 10:08:45 am »

Can't help you find your actual link requests.  But I do remember Brad Litz and Peter Sylvester's modification efforts. In case you haven't seen this thread that delves into such mods, you probably want to...
http://www.diyaudio.com/forums/subwoofers/171294-fixing-labhorn.html

My take from having built 4 off the original plans, is those plans are fine unless you're wanting to only use 1 or 2 together....then I'd probably work on smoothing.
That said, I've found 2 labs together to measure as smooth as other horn subs that nobody ever talks about needing smoothing...so it's kinda just a matter of how important is it to you...
I use a system weekly with 2 Labs/side in a club. Works pretty well. Live Rock music.
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