stereo question adding amp w/ stock subwoofer (Page 1/1) qwikgta FEB 27, 02:14 AM questions. my 88 has an aftermarket Pioneer head unit using the stock wiring harness to the factory sub and 4 Kenwood speakers. Looking at the factory wire diagram, the 4 speakers provide the subwoofer amp with a signal and they also travel from the head unit to the speakers w/ out being amplified, so they must be getting their power from the head unit. In other words, if the Pioneer head unit has 50x4 power rating, the head unit itself is what is providing the power to the 4 Kenwood speakers, while the subwoofer amp is powering the woofer under the dash. (sub was upgraded to a RD replacement one). So, can I keep the wiring going from the head unit to the factory sub amp, using the factory wiring and place an amp between the head unit and the 4 speakers? Also, since the Pioneer head unit has RCA outputs can I use them to provide the signal I need to the "other" amp while keeping the speaker wires running to the factory amp. Can both RCA outputs and wire outputs be used at the same time, or does using one cancel out the other. I know many are going to say "get rid of the factory sub and amp" but they work just fine and I like the factory gain control in the overhead console. I just need more power to the other speakers. Plus, I am adding another set of 6.5 speakers to my Fiero Store door panels. So in total, i'll have 6 speakers running off the amp and i'm not sure the factory head unit will be able to split up the power to the 6 of them effectively. TIA fierobear FEB 27, 01:50 PM I have a similar set up in two Fieros, an aftermarket stereo with the factory subwoofer. The question need answered is whether the speaker wiring from the head unit to the subwoofer amp is speaker level or line level. Obviously, the output from the subwoofer amp is speaker level. Another good question to ask is whether the subwoofer amp does crossover of low frequency from the other speakers. qwikgta FEB 27, 02:51 PM agree. unless someone has a good understanding of the factory amp, i assume that there is some kind of crossover in the factory amp to delete the high/mid sounds. I plan to leave the wiring from the head unit to the factory amp, it works fine. As it is now, if i turn down the sub, i get sound from the 4 Kenwoods but its not a pleasant sound, all highs. My plan is to install a 4 channel amp with the front 4/10 and rear 4/6 on the "front" channel and the door mounted 6.5 on the rear. the door mounted speakers are dedicated "mids" w/ out any tweeter so I plan on using setting up the amp for mids - low freq output. Not too worried about having the 4/10 and 4/6 on the same "front" output, the car is so small its not that big of a deal about F/R sound. I also plan on putting the amp behind the pass seat and running the speaker wires back up to the head unit, taping into the speaker (out) wires there. Save the time of pulling the seats, carpet and interior plastic to get to all the speaker wires. If the wires need to be updated, ill do that in the spring-summer when its warmer out. When I google for using both the RCA outputs and speaker wire outputs I get nothing back, I guess i'll just install it, wire it and hope for the best. Rob qwikgta MAR 02, 05:58 PM bump for some assistance. short version. stock radio sends signal from 4 speaker wires to sub amp. sub amp sends signal to subwoofer. stock radio also sends speaker signal to the 4 speakers, w/ out getting amplified, so the stock head unit is providing the power for those speakers. is this how it works? If so, then if you replace the factory head unit w/ aftermarket using the factory wiring, then the aftermarket unit is now providing the power to the 4 speakers. is it possible to put an amp in this system using the RCA outputs from the aftermarket unit to the aftermarket amp? In other words, can you use both the RCA outs, and the stock speaker wires at the same time. I can not find this in a google search, I must not be using the correct wording b/c i keep getting tons of info on using RCA out to amp data but nothing addressing using both RCA/speaker wires. Fierobear, thanks for the input.