From: jreiser@scott.skidmore.edu (jason reiser)
Newsgroups: rec.audio.car
Subject: Re: Alternators and Amps
Date: 28 Sep 92 19:16:08 GMT
Distribution: na
Organization: Skidmore College, Saratoga Springs NY

Hey Trav,
 
> I will be running two Punch 45 amps, and I am not sure if I need a
> bigger alternator?  If I do, how much should I expect to pay for one?
> I have a '91 Talon and ran a Coustic 460 before and never seemed to
> have any problems.
> 
Actually, a lot of people would consider upgrading the alternator in
this system, but from my own experience with the vehile, I'll tell you
it is not necessary.  I presently have two amps (a Hifonics Gemini
50x4 and an Orion 275sx).  The Hifonics is running mids and tweeters
at 4 ohms and the Orion is running a 12" RF pro sub at 4 ohms (1/2 the
rated impedance).  Even with this much current draw, I have been very
surprised that the stock electrical system in my Eclipse GSX can keep
up.  The radio and dash lights DO NOT dim on heavy bass rifs.  When I
planned the system, I had planned to add the alternator when I added
the Orion amp.  I installed the amp and have noticed zero problems.
Given that, I don't think that a pair of Punch 45's would be any
problem.

> I am going to run one Punch to 2 12" Kicker Competition Subs in sealed
> 1.9 cuft enclosures and I was wondering how to wire them.

What impedance are they, or have you purchased them yet?  A pair of 4
ohm subs could be wired in stereo (one per side) or in series to a
bridged mono channel.  Parallel wiring of two 4 ohm subs would show a
dangerously low impedance of 2 ohms to the bridged output.  (Remember
that when you bridge an amp, you add the left + right power AND the
left and right impedances.  So an amp that is stable to 2 ohms stereo
will be stable to 4 ohms mono!)  If the subs are 8 ohms, you could
parallel them to show 4 ohms to the bridged amp.

> Also I will
> be running 2 Kicker 14mm tweeters, 2 Kicker 5 1/4" mid-ranges and 2
> Sony 6x9's off the other Punch.  How should I wire them, and how should
> I run them through the crossover?  The tweeters and 5 1/4's have there
> own passive crossovers that came with them, so do I need to run them
> through my active (Coustic XM-3) crossover?

Your XM-3 has more options than you will be using in the beginning,
but that's the way to build a system, right?  Run either one or two
(your preference) inputs to the crossover and use one high pass output
and the sub output.  You'll run the sub outs (low pass of course) to
one amp that powers the subs, and run the high pass output (either
one) to the other amp.  For the sub frequency, use your ears and taste
to determine a point somewhere between 50 and 200 hz. (approx) and a
high pass between 80 and 250 hz.  The subs are pretty easy to figure
out from there, but the other speakers might create a little
confusion.  The high pass frequency you choose will serve primarily to
protect your speakers from attempting to produce low frequency notes
that they are not designed to do.  Set the point listening to the
speaker that has the weaker bottom end (more likely the 5.25").
Wiring from the amp is as follows...  Run the rear speakers in stereo
as normal.  Run the front speakers through their passive crossovers
and parallel the fronts with the rears.  (Think of the front separates
as being one speaker as far as wiring at the amp is concerned).

> 
> Thanks alot,
> 
> Trav           Soon to be boomin' again
> tjd28@cas.org

No Problem.  If you have any vehicle specific questions, drop me some
E-Mail.  I'd love to help!

				- Jason