[rescue] Workers of the World, Unite!

[Joshua D Boyd]

On Mon, Jul 22, 2002 at 02:13:03PM +0000, Kris Kirby wrote:

> > > I build a `sub' from a cardboard box and two 10-ohm 6x9's from my wrecked
> > > 1987 Buick Lesabre.
> >
> > Was it any good?  Aren't car speakers usually supposed to only be 4 ohms?
> 
> GM, go figure. It's OK, up until it starts rattling because of the power +
> frequency. My next sub will be a folded horn. I am seriously thinking
> about building a folded horn for a 6x9 or 8" (or 10") speaker as a sub in
> the back of the Sentra. This single largest problem is that I'd have to
> cut a hole in the back deck for the `breather' hole. That or build a
> folded horn beneath the existing 5" speakers on the back deck.

Well, I'm not an expert in sound reproduction, but IMHO, the best
results come from using a large speaker for a woofer, not from fancy
box techniques.  For awhile, the best indoors subwoofer (never done a
car one) I had was made from a 14" speaker taken from a peavey
monitor.  It just took the audio straight from the amp with no fancy
electronics.  

Now, I suspect things would get messier in the case of a car, where
such a speaker would need to go in the trunk, where the rear deck and
rear seat are going to muffle it, so maybe something fancy is needed.
But if it were me, I'd be looking for a plainer/purer approach, like
modifying the back dash to just hold 6x9s.

But, for now, I'm sticking with what is easy for the car, and wishing
I spent more time at home to make all the work I've poored into trying
to get the best on a budget worthwhile.  I hate being so busy.

BTW, did you do anything to make up for the ohms mismatch?  I could
have sworn that even if GM did something wierd, most car stereos, and
the stuff that comes with the Nissan specifically, are designed for 4
ohms.  My recall is that 10ohm speakers on a 4 ohm amp puts to much
load on the amp, and that if you aren't going to match the amp to the
speaker, then at least the speaker should be a lower ohm-age. And it
should be easy enough to add a circuit to adjust for the different
speakers.   A 6.6667ohm resistor network in parallel with the speaker
would bring your resistance down to the desired amount.

-- 
Joshua D. Boyd