Date:         Thu, 21 Apr 1994 15:43:40 -0500 (CDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Werner Kenneth Hellmer <whellmer@icaen.uiowa.edu>
Subject:      Re: Vanagon Subwoofer

vas ist los?
	More audio questions, definintely more fun than the report about 
	nephelometric advances for the measurements of turbidity I just 
	finished for the UofI water treatment plant.
	
	I would have to strongly advise against placing subs anywhere near
	the roof. Being that close to the sheet metal and parallel to the
	direction of soundwave propagation, you are all but guaranteed to 
	to reach resonance (really nasty metal buzzy sound:) ) at some 
	frequency the subs put out, probably 40-80hz. Please...
	Proove me wrong ;)
	
	Martha's right. That little Tandy RS sub is decent for the $. May I 
	also suggest, if you go with it, to install an inexpensive  subsonic 
	filter to remove all waveforms below about 40hz. (The thing will growl 
	when trying to reproduce these frequencies, and you won't be able to
	tell its there unless you listen to gangster rap, classical, or 
	digital music) Tandy RS drivers are ok, just make sure to stick
	w/ the 4ohm models, otherwise you will have different design 
	considerations.
	
	As far as Q goes, this is a big theoretical argument. From practice
	it depends on what kind of bass you like and what you want to hear/
	spend. While using a lower Q is less than ideal, it can be done.
	Porting, for instance reduces the req'd Q signifigantly. The important
	thing is to keep the front and back of the speaker sonically separated.
	As long as the negative and the positive wave do not meet at "close
	distances" you will be fine. A simple barrier to prevent this is all
	that is truly necessary. The smaller Q is another reason to stick w/
	8 inchers. 
	
	Consider lurking in rec.audio.car for a while; underneath all the
	"which cd player is best" bs there is some good info to be had.
	Keep the questions bouncing. I'm always ready for a new idea!
	 
*Werner Hellmer		whellmer@icaen.uiowa.edu