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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Subwoofer FUD Forum Archive => Topic started by: andreas on April 26, 2004, 11:00:40 AM

Title: Sound Quality
Post by: andreas on April 26, 2004, 11:00:40 AM

Dear All

The virtues of the lab sub as pure sub woofer is beyond question. But can anyone comment subjectively on the sound quality if used with proper eq up to - lets say - 200 Hz. The roll off starts around 150 as I can see from the published response plots.

Cheers
Andreas

Title: Re: Sound Quality
Post by: Brad Litz on April 27, 2004, 02:56:44 AM

See v3.0 predicted response here:

http://srforums.prosoundweb.com/index.php/m/1364/500/5bee6ea c8c4aab7c978178d0573ffc17/?SQ=c934a917d19af4e2afe4dea4c5c2fe 31

Title: Re: Sound Quality
Post by: Brad Litz on April 27, 2004, 02:59:45 AM

v3.0 looks even better in AJhorn analysis:

Title: Re: Sound Quality
Post by: andreas on April 27, 2004, 08:09:40 AM

Thanks Brad

response curve looks mighty good, it would be cool though to get som listening impressions of the horn up to 200Hz. As it makes some freedom when considering construction of a horn loaded top box.

Cheers
andreas

Title: Re: Sound Quality
Post by: Brad Litz on April 27, 2004, 08:24:05 PM

I'll measure and post the response when I get them finished.

Title: Re: Sound Quality
Post by: Sound Construction on May 18, 2004, 02:02:30 PM

dude... they're subs

Title: Re: Sound Quality
Post by: Jens Droessler on May 23, 2004, 11:02:30 AM

30 to 200Hz is a big stretch. That's why the LABsub is called LABsub. Best solution would be a filler cab that can do 80 - 200Hz in really good quality. I don't think that it's good idea to force a linear plot by EQ.

Title: Re: Sound Quality
Post by: Brad Litz on May 23, 2004, 11:09:03 AM

Jens Droessler wrote on Sun, 23 May 2004 10:02

30 to 200Hz is a big stretch. That's why the LABsub is called LABsub. Best solution would be a filler cab that can do 80 - 200Hz in really good quality. I don't think that it's good idea to force a linear plot by EQ.

Two LABsub v3.0 no EQ.

Title: Re: Sound Quality
Post by: Sound Construction on May 24, 2004, 01:57:56 AM

Brad,

I don't have a lot of experience reading graphs like this, so I have a few questions. was the source matereial a full frequency burst or a sweep? If it was a full frequency burst these results would mean that the amp and driver are able to simultaniously reproduce lower (frequency's requireing long slow excursions) as well as the faster transients up to 200 hz at approx the same efficiency.

What kind of amp did you use for the tests?

If this is the type of frequency response that can be expected in real world it would mean that the low mid of a 4 way system (like you would have if you matched a set of labs with some EAW 650's) could be eliminated and with a simple crossovers adjustment. Do the measurements you've gotten so far indicate that the Labsub could/shoule be used to cover such a large frequency range in a live sound application?

I saw the new web page for v.3. Your craftmanship is simply astounding.

Title: Re: Sound Quality
Post by: Brad Litz on May 24, 2004, 03:16:41 AM

The test signal was a full frequency maximum length sequence or MLS. It is basically a pseudo-random sequence of pulses. The MLS has a quasi-flat power spectrum. The spectrum envelope follows a square(sin(x)/x) law and falls by about 1.6 dB at 1/3 of the sampling rate (48 kHz).

The amp was a Sony TA-E9000ES.
http://www.sel.sony.com/SEL/consumer/ss5/home/homeaudioes/es poweramplifiers/ta-n9000es_specs.shtml

The measurements indicate a 12dB/octave roll off beginning at 200 Hz. A 12dB/octave low pass filter placed at 200 hz would result in a 24 dB/octave acoustic response. This would match a 24 dB/octave 200 Hz high pass into the midrange.