Does anyone have information on how to tap into the current wiring system and add a second amplifier solely to power an aftermarket sub in the trunk? I'd rather get some JL Audios than go with the factory subs. I just need to know what's involved in adding that second amp.

Thanks.

I read all the strings an heard nothing about putting in a cap for all that power on the subs, this way it would not put a strain on lights and alt. Believe me its worth the extra money then buying a new alt every 6 to 12 mo.

The OEM dash unit doesn't have low level phono outputs like the aftermarket units all do but all remote aftermarket amps have optional speaker level inputs so you can tap into your existing rear speaker wires to get the sound to the sub amp.
Now, as for powering the sub amp, they use alot of current so you'll need to wiring a power source to the battery with a heavy guage wire and good high current fuse located at the battery. The amp is switched on/off usually by the antennas power lead (low current) and you've already got that back there now.
Places like BestBuy, Circuit city, etc sell amp wiring kits if you want to simplify the install but some of those kits get kinda pricey IMO.
If you'ld rather not install it yourself, those places will also install their stuff in your car too.

There's still one problem... if you're going to use a 12" sub to reproduce, say ALL the sound below 120HZ, you should ideally also be pulling the input from all four 8" woofers in the car. If I remember correctly from the dolby diagram, there are two on the hat shelf and one in each of the doors; the ones in the doors are receiving different musical info than the ones in the back. Perhaps you could use two 12" subs, run one off of the front left and one off of the back right woofers via a crossover, then use a bass blocker on the other two to most accurately reproduce ALL of the low frequency bass. It is unlikely that all the bass would be concentrated in one quadrant (i.e. left front, or left rear... usually it would be reproduced in at least two speakers). Anyone looked at the pro-logic diagram lately to see if this makes any sense?
-Jon
--
CPT Jonathan T. Belmont-- '99 C70R 48K 'Valdemar'

There's an excellent post on www.swedespeed.com (the most active C70 board). Click Forums > C70 (1997-present). There's a post titled "2000 C70 Stock Amplifier" and someone by the alias Audioguy writes a long, detailed and accurate outline of the C70 audio system.

Gary, great post. For those interested, I also found this helpful link on Crutchfield....
http://www.crutchfield.com/infocenter/S-ZgVoUMv2urR/car/amplifiers_install.html?page=3

I'm going to give it a go myself within the next few weeks. I'll post with the results.

I've been doing the "high perf" soundsystem stuff in my cars for about 10 yrs now and one learns alot by trial and error but if you know any driving age teenage males, most are REALLY into this stuff, it's in their blood. Unlike me, most of those younger guys are more into pure BASS for rap but they learn alot from all the other kids. My own 18 yr old son has his "booming system" in his old 744 and we hear him coming when he gets near the house. Now he complains about his lights dimming with all that power (2 800W amps powering 2 12" subs!)....yeah! His 54W alternator's not exactly able to keep up with all that, the plot might thicken there.

Sounds like he needs a capacitor or two!

An appendix to installing an aftermarket amp in a C70...if you plan to splice the speaker wire and connect to speaker level input connectors, one might want to splice the wires for the rear deck speakers BEFORE they connect to the factory amp (between the receiver and the factory amp)...Amp source to amp destination could be harmful to your aftermarket amp.