Re: A Subwoofer Question

["Frontstage" <frntstg9@allinux1.alliance.net>]

first question, what kind of drivers are you using that have an impedance
of 18 ohms?
next, what are the characteristics of your sub?  what type of enclosure
does it require?
next, never seen/heard a bandpass box i really liked.
next, i usually use a sealed enclosure myself as i mostly listen to jazz
and prefer tight, accurate bass.
next, ported boxes are more efficient than sealed enclosures but they tend
to be boomy withing the tuning range of the port.  another thing to watch
out for is port turbulence.  
next, you can't just take any old sub and throw is into any old box.
hope this helps
frontstage	

----------
> From: Brooks Ellis <brooks@fortnet.org>
> To: quattro@coimbra.ans.net
> Subject: A Subwoofer Question
> Date: Monday, August 12, 1996 1:26 AM
> 
> 
>         I'm posting this here 'cuz the newsgroups are full of noise and
BS.
> My required Audi content? My system is installed in the '90 100Q I have.
(
> Although, I really want a '90 200TQ!! That would kick ass! )
> 
>         Anyhow, I have a 10" sub hooked up in the trunk. It doesn't bump,
> rattle windows, etc.. It just sounds good. Great in fact! My current
> dilemma, is that I'm not sure I like the way it is set up. It will work
> Ported, sealed, bandpass, maybe free air.. Basically, whatever. 
>         Currently, I have it in a 1.75 ft^3 box ( a bit large.. ) driven
by
> a 120w (bridged) amp. I have a passive crossover at ~80-100 Hz. Then, I
have
> the rears driven by the same amp, with about 18 ohms of resistance per
> speaker, and they are crossed over about 100 or 200 Hz. ( passive, also
). 
>         The sub is where the action is though. I have ports in the box,
but
> the ports are stuffed, so the box functions as a sealed box. I like the
> sealed box sound better, it will function at a lower freq., and has
tighter
> bass. My question is - What will happen if I go ahead and port the box
for
> 10, 15, or 20 Hz? How will the driver function? Will it be louder at the
> higher freq's? More boomy? ( yuck ) Just plain louder, but have the same
> accuracy? I think that porting it for 15 Hz sounds like a good idea, but
I
> do not know how it will function compared to the sealed box. Any ideas?
> 
> Brooks
> 
> PS - please cc: to me as well as the list...Grazie!! 
>