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Author Topic: LAB-sub based on 18” seismic driver.  (Read 12560 times)

leon douven

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LAB-sub based on 18” seismic driver.
« on: July 14, 2005, 03:07:04 pm »

LAB-sub based on 18” seismic driver.


Hello all,

Hope some of you can help me out with 2 questions I have.

1 In the history of the forum I read that Tom Danley had an alternative design for the LAB-sub  based on the 18” Seismic driver. It said somewhere that he aborted the idea, because the cabinet would become physically to big. Is there any information regarding this alternative design, drawings/specs? The few links in the history of the forum turn out dead.

2 Are there sub-designs based on physically coupling several LAB-sub-size cabinets to one big horn. What possibilities would a horn the size of for example 4 coupled LABsub-size boxes give. Since it is crucial that the driver compartment is highly air tight it could be made in one of the cabinets (big enough to house 4  18” drivers !!) To form the actual horn one could couple multiple truck-pack-size cabinets. It cant be so hard to couple cabinets air tight enough for the horn-section.

By the way, I started making some sawdust…. The Christmas tree has to be a lil bigger this year honey…

Best regards
Leon Douven
Heerlen
Netherlands
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Brad Litz

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Re: LAB-sub based on 18” seismic driver.
« Reply #1 on: July 14, 2005, 07:30:38 pm »

I don't believe the 18" design was persued at all.

Just stack two of these:

index.php/fa/2090/0/
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Brad Litz

Finn

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Re: LAB-sub based on 18” seismic driver.
« Reply #2 on: July 20, 2005, 11:02:17 pm »

would a single 18" in a modified lab horn produce more output than the dual 12" design?  (assuming you can enlarge the enclosure to fit the 18)
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peter.golde

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Re: LAB-sub based on 18” seismic driver.
« Reply #3 on: July 20, 2005, 11:27:17 pm »

no
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Peter Morris

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Re: LAB-sub based on 18” seismic driver.
« Reply #4 on: July 21, 2005, 01:38:45 am »

This probably fairly close to what you would call an 18-inch version of the LAB. It uses an 18sound 18WL1400 and a slightly higher compression ratio.

Here is the frequency response - the top trace is EQed the bottom was the raw plot

http://www.nucleusaudio.com/18in%20bass%20horn.jpg

Since these plots were made there have been several modifications made.  The box had resonant issues and required more bracing than the LAB, and there was an air leak where the cable entered the speaker chamber that had not been sealed.

The result was a much smoother “text book” response.

I terms of output, if you used the seismic driver you may even get a bit more than the LAB, the issue would be stress on the cone and making the space big enough to fit the driver in.
With an 18WL1400 it is probably a couple of dB behind, but the box is way easier to build.

FWIW depending on what material the LAB is made out of, I suspect it may benefit from some additional bracing.
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Chris Jensen

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Re: LAB-sub based on 18” seismic driver.
« Reply #5 on: July 21, 2005, 02:48:15 am »

Just some random thoughts on the whole LAB project, but they fit well into this post I think.  What was the process of this design?  What many fail to realize, my opinion, is that the LAB was built backwards compared to what most people think the process is.  It's not about the driver, it's about a working system.  The LAB was built based on a desired performance.  It wasn't built then tested.  I think that many fail to realize that no matter what driver you put in the box, only the LAB12 will work the best.  Putting an 18 in a bigger version will not make it any better.  It is more complex then just making it "bigger", the math involved is not simple.  The LAB is a single purpose, fine tuned system, you change a part of the system and expect it to work.  You must desing a new system based on what you want the system to do.  You can't just slam any old engine into any car and make it work right, the transmission has to be mated right, and the computer has to function right, etc.  Point is I dont think any of these questions of will this driver in a bigger box of the same kind be better.  Build 2, 4, 8, or 12 of them and then see if you need a bigger drivers in a bigger box, I suspect you wont.  I know that my one corner loaded can do A LOT of "damage".

Chris
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Finn

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Re: LAB-sub based on 18” seismic driver.
« Reply #6 on: July 21, 2005, 06:08:59 am »

Chris, what i meant to say was that if a horn was designed around a powerful 18" driver, or a driver designed with a box concept in mind, could you expect greater output particularly for 1-2 boxes coupled?  i realise that you can't just shove a driver in a box and expect it to perform miracles.... but if a box roughly the size of the lab were designed around an 18" it'd be interesting to see how it performed, that's all Wink
Finn
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Walt de Jong

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Re: LAB-sub based on 18” seismic driver.
« Reply #7 on: July 21, 2005, 09:58:29 am »

Take a look at the EM acoustic Quake 18" horn. It uses a PD-1850 on a 270cm long horn. A guy here in holland replaced his 6 LAB-horns with these EM-horns. He says the EM 18" horns sound better and go just as loud and almost as deep.

Best regards,

Walt
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Steve Shafer

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Siesmic driver is now CGN which is used by Bassmaxx
« Reply #8 on: July 21, 2005, 12:00:13 pm »

Last i checked the Siesmic/Aura driver is no longer in production.  However, CGN produces a driver called the Neomaxx which is a totally upgraded version of the Aura/Siesmic, and this driver is a mainstay of the Bassmaxx horn loaded subwoofers.  

Bassmaxx uses this neo 18 over the McCauley 18, and when i last spoke to David Lee Bassmaxx was using 18 Sound 18's in thier budget model horn loaded B3's and B0's.

Here is the newest incarnation of the Aura/Siesmic/CGN 18

http://bhivemotor.com/index.html

Steves
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leon douven

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Re: LAB-sub based on 18” seismic driver.
« Reply #9 on: July 22, 2005, 01:05:27 am »

"By Peter"
Since these plots were made there have been several modifications made. The box had resonant issues and required more bracing than the LAB, and there was an air leak where the cable entered the speaker chamber that had not been sealed.

The result was a much smoother “text book” response.



Hi Peter, are there any drawings of your improved 18"based design??

best regards
Leon

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