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From: gvcormack@watmum.UUCP (Gordon V. Cormack)
Newsgroups: net.audio
Subject: Re: subwoofers (bass from small speakers)
Message-ID: <303@watmum.UUCP>
Date: Sat, 26-Oct-85 09:00:46 EDT
Article-I.D.: watmum.303
Posted: Sat Oct 26 09:00:46 1985
Date-Received: Sat, 26-Oct-85 19:16:50 EDT
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Organization: U of Waterloo, Ontario
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> Ahem...the audio-pro B2-50 subwoofer uses (2) 5-1/4" drivers and I
> believe it is fairly flat down to 20Hz.

>  ...  other testimonial evidence

I have a couple of comments.  First, speaker manufactures LIE about
their low-end frequency response (and accuracy, for that matter).
I don't know about audio-pro, but look for independent test results
to verify any manufactures claims.  Polk, for example, claims the
monitor 10b is 22Hz - 22Khz +- 2db.  Tests in SOUND revealed it
was pretty flat down to 40, but was down >10 db at 30.  That still
makes it a pretty decent speaker, but not as fantastic as claimed.

Second, it isn't hard to make small speakers have excellent low-frequency
response AT LOW OVERALL SOUND LEVELS.  But in order to get
a decent sound pressure level out of them, small speakers would have
to have a cone excursion of several inches.  This is nearly impossible
to accomplish, and were it accomplished I doubt that the suspension
would be very linear.  Even if a linear ultra-long-throw suspension
were developed, there would still be doppler distortion of the higher
frequencies (maybe this wouldn't be a problem in a subwoofer).
So, when you talk "frequency response", make sure you find out at
what Sound Pressure Level.

Here are some test pieces to use when checking out the bass response
of a speaker system (see if you can play them at a realistic level). 

 Time Warp (Telarc cd-80106)  1st and 2nd cut.
 1812 Overture (Telarc cd-80041)  12:00-15:20 in particular
 Bach Toccata (Archiv 410 999-2)
 Pink Floyd - The Wall (CBS C2K-36183) "Don't Leave me now" --
               has some very low synthesizer tones, but they are not
               all that loud.