Aftermarket Stereo Head Unit Install Question

[BumbleZ]

I have the stock alpine passive/active amp and 10-speaker system in my 94 325is. When replacing the stock head-unit with a 50Wx4 max head-unit (like the Pioneer P730), do you use both the stock alpine amp and the built-in amp from the new unit? One installer said that you did because the stock Alpine amp is not a true "active" amp (whatever that means). The pioneer has 3 RCA outputs but I know that the Alpine only accepts line wires. I will have the Sub RCA from the Pioneer connected to a 150Wx2 rms amp and 10" JL sub. Thanks for your help.

[jayhudson]

I don't know if the factory amp is made by Alpine, but if you're talking about adding an aftermarket head unit to a factory amp then yes, you use the speaker outputs from the head unit. The reason you can do this is because the factory amp doesn't actually operate on a line level signal. It's best to use a head unit with a wide range of volume adjustment because you're feeding an amplified signal into another amp. Example: Kenwoods go from 0-35. Eclipse goes from 0-80. The Eclipse is a better choice because each increment of volume on the deck is smaller. Therefore, the amp doesn't jump so much with each increase in deck volume. Jay

[BumbleZ]

Thanks, Jay. One more question. I just got the Pioneer installed (the volume increments are 1-100) and the sound is greatly superior to stock. One question though...the volume of my front door and kicks are much louder than the rears at equal fade. With the stock head-unit, they were about the same. Plus, the Pioneer seems to want to put mainly bass in the back speakers (even though the rears are really a mid and tweeter, right?)

Is it possible that the rears aren't hooked-up to the Pioneer's amp? Any ideas?

I think that the rears are really just to add some fill-in, as I installed a JL sub in the trunk, but I'd like a bit more sound from them. Thanks for your advice!

[Racer_X_Kidd]

yes the back are really mids with tweaters and if u want more bass from ur subs then go to ur installer and ask em to tune it right......i just had a $2500 system put in my car and ive been back 3 times to ask them to set it up different and stuff if u drop anywhere near the cash that i did to get it they will help u out with whatever u need

[BumbleZ]

The bass from my sub is fine: the Pioneer's sub RCA is connected to a 150x2 rms amp in the trunk, and I use the Pioneer as the crossover and power control.

My problem is that the rear speakers are not producing the same amount of volume as the fronts with the Pioneer. Does anyone have any idea why this might be?

[jayhudson]

You are now feeding a different signal to the factory amp than it was designed for. It probably has something to do with the internal crossovers in the amp. As long as the rear speakers work OK, don't worry about the fact that you have the fade adjusted differently. On the other hand, you may have some crossover or speaker EQ thing going on in your deck. I'm not familiar with the Pioneer products, but some decks allow front and rear crossover points or specifying the type/size speakers being used. Check out your owners manual. I have my rear speakers removed to let more bass in. Don't need 'em if you do the fronts right. Jay