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From: miker@polari.UUCP (Mike Ranta)
Newsgroups: rec.audio.high-end
Subject: Re: Subwoffer Driver Rec's Wanted...
Message-ID: <13174@uwm.edu>
Date: 17 Jun 91 12:49:57 GMT
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Approved: tjk@csd4.csd.uwm.edu
Originator: tjk@csd4.csd.uwm.edu


In article <13024@uwm.edu> shimizu@unix.sri.com (Dan Shimizu) writes:
>
>My cohort and I are on our devilish way to become speaker
>designers and we're trying to design a pair of subs to go
>along with some sattelite speakers we are building.  I
>prefer sealed box designs, so I don't have to go through the
>hassle of tuning and estimating Ql (box loss) that is required
>for vented box designs.  My question is what is a good driver
>to use for a sealed sub?  I just heard about the Audio Concept
>12" (AC12 Mk.2).  They sound good, does anyone have any experience
>with these drivers?

I'm listening to a pair of AC12 subwoofers as I write this.  I have
tried several high quality 10" and 12" drivers in my quest for the
perfect subwoofer, and have to admit the AC12s come awfully close!
 
I like fast, clean, tight and solid bass down low without excessive
distortion or non-linearity at high levels.  The AC12s do this very
well in a sealed 4.0 cubic foot enclosure.  You can also use two
per side in an isobarik configuration in a 2.0 cubic foot enclosure
if you want to give up 3 db of efficiency (Audio Concepts does this
with one of their subwoofer kits).

They have a very linear cone suspension yet are reasonably resistant
to "bottoming" when driven hard.  With 150 watts driving each of them
in my system, the amp usually clips before the drivers complain.  They
are an honest 90 - 91db at 1 watt/1 meter.

My second choice (less expensive too) would be Madisound 10208 10"
drivers in a 1.5 - 2.0 cubic foot sealed enclosure.  They are a few
db less efficient and their 3db down point is a half octave or so
higher, but they have the same subjective "tight" sound and take
power well.

>On the other hand, what drivers are good for vented subs?

In my opinion, there are very few drivers that work well in vented
subwoofers.  On the computer, several look great, but in practice,
nearly all of them distort and/or bottom badly at frequencies well
above and below the tuning frequency of the enclosure when driven
hard.  You are also correct about having to second guess box losses
and other factors.  As you're probably aware, ported designs also
roll off at 12db per octave versus 6 for sealed systems.  For this
reason and the first one above, they do not respond to "EQ" well
if they require it (or the owner likes it).  There are exceptions
to all this, but you'll likely be happier with a good sealed system.

miker@polari.uucp (Mike Ranta)