Contour Enthusiasts Group Archives Forums Modifications Audio Can subs and amp be added to factory system?

hey guys

i was wondering if subs and an amp could be added to the factory amped system without changing the factory head unit. i pulled out my system from my last car and would like to install the subs and amp this weekend if at all possible. thank you in advance for the help.

Yep, you can either:

(1) Use speaker-level inputs on your amp (if it is so-equipped)

(2) If no speaker-level inputs, pick up a pair of speaker-level to RCA converters ($20 or so from BB/CC)

You've just got to splice into the factory speaker wiring (behind the HU would probably be easiest).

If you get an amp that has good gain system all you need to do is splice into the hu output before the factory amp. get some rca cables and cut the ends off on the hu side and run the wires stright to the amp. Factory head puts out about 1 volt IIRC.

i did it...it worked great (aside from the fact that my sony sub is junk). Like they said, all i used is a radio shack line-0ut converter (radio shack part number 12-1338, i spliced it in right behind the radio..the radio can be shoved back into its slot with the line converter behind it) it has adjustable gains on it which really helps filter out distortion IMO. after that peice, everything else is the same....wiring, mounting, setting levels, is normal..

Yes it can be done.
The question is why would you want to do it.
The facory HU puts out 1-2V, that's horrible.
I could introduce distorion into that with a hair dryer or a well placed magnet.
A bad aftermarket HU puts out 2-3V, a good one puts out 3-5V, and a great one put out 5-8V.
A competition sound system will work between 12V and 14V.
How much voltage you HU puts out is directly related to how loud and how good your sound system will sound.
The average street person runs around 5V.
There is no point in amplifying a signal (regardless how could of an amp, if the signal is crap).
1-2V output effectively decreases the range of frequency your system can reproduce.
Why? Because it take more power to reproduce certain frequencies.
The average human hearing range is 20Hz to 20kHz.
A competition sound system will reproduce one octave below and one third (1/3) octave above that. That makes the range 10Hz-25kHz, which can be done at 12-14V.
5-8V will do from 35Hz-20kHz,
3-5V will do 40Hz-18kHz,
2-3V will do 55Hz-15kHz,
and 1-2V will do 80Hz-12kHz.

Funny you should ask.

I was looking through wiring diagrams in my Haynes manual the other day and it shows an OEM audio option which includes a separate amp and subwoofer combination. Don't believe it was ever actually offered as an option in North America.

Can you imagine -- OEM HU, separate amp, subwoofer amp -- three boxes to produce a sh***y sound.

RE previous post. Quality of pre-amp output is not related to line-out voltage.