ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  
Pages: 1 [2] 3  All   Go Down

Author Topic: labsub modification  (Read 7934 times)

Art Welter

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4874
Re: labsub modification
« Reply #10 on: March 09, 2009, 04:39:26 pm »

Harry,

Having the drivers in series rather than parallel would reduce the level by 6 dB assuming the amp’s output voltage was the same.

Have you tried the test I suggested yet?

Art Welter
Logged

Art Welter

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4874
Re: labsub modification
« Reply #11 on: March 09, 2009, 04:46:12 pm »

Jim,

The “floppy suspension of the Lab 12 driver” works fine in a ported cabinet as well as the sealed LAB design.

Many of us are using the Lab 12s in designs other than what you are using, and not having excursion related problems.

Art Welter
Logged

Harry Sookraj

  • Newbie
  • *
  • Offline Offline
  • Posts: 9
    • http://www.bubblersound.com
Re: labsub modification
« Reply #12 on: March 16, 2009, 10:04:54 am »

Art Welter wrote on Mon, 09 March 2009 16:39

Harry,

Having the drivers in series rather than parallel would reduce the level by 6 dB assuming the amp’s output voltage was the same.

Have you tried the test I suggested yet?

Art Welter


Hello again,

I tried the experiment, and if I read your directions correctly, the cone has the least amount of excursion right b/t 47hz - 50hz. As I was listening, I did notice the cone reaching max excursion at about 35hz.

I have burnt out at least 6 lab12 drivers, but never ripping any part of the cone or suspension. As a matter of fact, still looking for a supplier to sell me some recone kits. Sad
Logged
Harry Sookraj
Bubbler Sound System
"talk is cheap, bass is everything"

Art Welter

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4874
Re: labsub modification
« Reply #13 on: March 16, 2009, 05:34:21 pm »

Harry,

So I guessed within two HZ your FB, the gray computer between my ears still works.
My bet is the Frankenlab is quite loud at 50 HZ also, right in the middle of where the normal LAB 12 design has a dip.

Since your open chamber Lab sub FB is about 48 HZ, you would  be best HP at 40 HZ, no need to put much power into the box below what it will produce well, and it is dropping about 24 dB per octave below FB.

Are the Lab 12 driver coils burnt, or just open?

There was a defect in some early Lab12 that Eminence would fix under warranty, I had three of four fail at random intervals. That defect (a bad crimp where the voice coil wire crosses behind the former, IIRC) occurred without any discoloration. If you have burnt the coils they are not covered, of course.

Art Welter
Logged

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 9010
Re: labsub modification
« Reply #14 on: March 18, 2009, 07:57:58 am »

Art Welter wrote on Mon, 16 March 2009 17:34


There was a defect in some early Lab12 that Eminence would fix under warranty, I had three of four fail at random intervals. That defect (a bad crimp where the voice coil wire crosses behind the former, IIRC) occurred without any discoloration. If you have burnt the coils they are not covered, of course.

Art Welter

There was another problem they had for a little while in which the curing process wasn't working properly and the coils would fall off.

That has since been fixed.
Logged
For every complicated question-there is a simple- easy to understand WRONG answer.

Can I have some more talent in the monitors--PLEASE?

Ivan Beaver
dB Audio & Video Inc.
Danley Sound Labs

Gareth James

  • Full Member
  • ***
  • Offline Offline
  • Posts: 231
Re: labsub modification
« Reply #15 on: March 19, 2009, 01:42:01 pm »

Harry, from looking at the graph you posted and my own sim it would seem you might be able to smooth off the power distribution over the entire band by leaving one cover off and one sealed. You won't get either peak but a smoother more even response from 35hz on up. Of course this is the theory, would love it if someone could perform a test sweep to confirm this  Very Happy  Ideally on a standard LAB sub for the sake of easy comparison.
Logged

Raj Sookraj

  • Full Member
  • ***
  • Offline Offline
  • Posts: 121
Re: labsub modification
« Reply #16 on: March 19, 2009, 08:29:55 pm »

In the 2007 NYC shootout the speakers were next to each other which changes the response.  However, we leave space on both sides of every cabinet.  Here's the response overlayed with the TH-115.  Keep in mind my speaker were wired in series so each cabinet is about 12-16 ohms.  The last 5 inches at the horn mouth was eliminated which lowered the response about 3db if I recall correctly. Also, notice how similar the response and phase curve is.
index.php/fa/21697/0/
Logged

Art Welter

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4874
Re: labsub modification
« Reply #17 on: March 20, 2009, 08:26:39 pm »

Raj,

The horn being shortened by only 5 inches should have a negligible effect on a horn as long as the Lab.

The fact your cab was about double the impedance of the TH 115 would mean you can raise your cab by  about 3 dB (or lower the other 3 dB) to be apples to apples.

Having another cabinet on either side, if that was the case,  seems to have turned the cabinet, which seem to be operating like a scoop type enclosure, into a tapped horn, and lowered the FB  a few HZ.

Do you know how close the other cabs were to the side of yours when it was measured?

Art Welter
Logged

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 9010
Re: labsub modification
« Reply #18 on: March 20, 2009, 09:38:33 pm »

The cabinets were not measured in pairs-just singles.

The pairs came into play when listening.
Logged
For every complicated question-there is a simple- easy to understand WRONG answer.

Can I have some more talent in the monitors--PLEASE?

Ivan Beaver
dB Audio & Video Inc.
Danley Sound Labs

Art Welter

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4874
Re: labsub modification
« Reply #19 on: March 21, 2009, 01:37:52 pm »

Ivan,

Raj said:
“In the 2007 NYC shootout the speakers were next to each other which changes the response.”

Were there cabinets adjacent to Raj’s cab in the “ TH-115 and labish at 28V.jpg” response chart?

Art
Logged
Pages: 1 [2] 3  All   Go Up
 

Page created in 0.047 seconds with 20 queries.