<VV> LM coupe rear speaker housing

[Tony Underwood]

At 09:54 AM 12/18/2006, kaczmarek at charter.net wrote:
>---- "Kinzelman wrote:
>Andy
>I am RAPIDLY approaching the point where the Eastern ULTRA Monza is 
>driving me nuts without some Allman Brothers coming thru some 
>speakers.  I am getting a
>Custom Auto Sound Radio for it, with the CD Changer, and have had my 
>options open for what kind of speakers I would like to put in.
>
>This kind of thing seems custom made for my needs.  At one point 
>someone was going to make these---old Joe in Miami (where's HE 
>been?) was going to send me the plans for the one he made for the 
>rear package area but he never did send it.
>
>I would be interested in one---Pls let your friend know I'm 
>interested, and I'm sure many LM owners are as well.  He can build one for me.


If anyone is interested, I have a program for calculating port 
size/length for automotive speaker enclosures so as to correctly tune 
the enclosure to the speakers used.   It does require the use of 
better quality speakers with supplied T/S parameters 
(Thiele-Small)  for correct tuning.   It does a LOT for bass response 
via matching the speaker characteristics to the volume inside the 
enclosure, using ports to "fake" the volume into being resonant with 
the drivers used.    The dimensions of the enclosure, T/S parameters 
for the speakers, and that's it...  program calculates ports for best 
efficiency based on where you want the low freq roll-off to be.


The program I have is a bit dated but it's very effective (already 
has T/S parameters embedded for appx 400 different drivers) and it's 
been used to design some enclosures which have won prizes at car 
"sound-off" competitions.   I used it to design a woofer for my 
livingroom (doubles as a coffee table, uses a pair of 12" drivers) 
which works well enough to rattle the silverware in the drawer in the 
kitchen.    It can really boom out some noise.

For what it's worth, tuning a woofer to between 50 and 80 hz works 
out pretty nicely for most things, since that's where the majority of 
bottom end is gonna be in most music unless you're a fan of 
synthesized contoured bass such as in hiphop, rap, etc.    It's also 
easier to tune a woofer to these areas since it doesn't demand as 
large an enclosure to be efficient.    Boomcar junkies wanna have a 
woofer that's efficient at 30 hz, which usually means a box the size 
of a Crown Vic's trunk...  sure, no problem if you have a Crown Vic 
but in a Corvair there's nowhere nearly as much room, so compromise 
is the order of the day.     In my case I whittled the car, cooked up 
a ducted port woofer (in the trunk, fed low freqs through a port into 
the car via an opening under the dash) that ended up as a 
quasi-seventh  order enclosure, used a pair of Stillwater Design 12" 
drivers with an active crossover (I wanted a loud Corvair) and it 
worked nicely.    With 450 watts running the woofer (which would get 
the drivers hot enough to smell "burnt" if pressed hard enough) it 
would rattle the fillings in your teeth, along with loosening the 
majority of phillips screws in the car holding stuff together.

I got away from that sort of nonsense, now there's no desire for more 
than a couple-hundred watts total, max, for everything in the 
car.   The 12" drivers got sold to a boomcar fanatic, now there's a 
pair of "free-air" 8" drivers in their stead, which requires 
different tuning etc but that's no problem.


That package area behind the back seat is about the only practical 
place  (without cutting the car) in a Corvair where you can put a 
woofer that will actually do its job, if you're interested in a 
serious sound system in a Corvair.


tony..