Looking for Amplification Advice (for e36)

[p-lo]

Hi all,

I have a non-hk 10-speaker e36 coupe. Currently have:
-Deck: Alpine CDA-9855
-Subs: JL-10w0 x 2 with JL JX250 amp = 250w.
-Rear: Alpine R-Series 6x9 coaxial.

-Front: Currently stock, but I am planning on installing Alpine R-Series 5.25" components (to match rear)

I have an old amp I would like to use. Alpine V12 MRV-f300s: 50w x 4ch, or 75w x 2ch RMS.

MY QUESTION: If I used the V12 amp, would it be better to amp just the fronts at 75w each or all 4 speakers at 50w?

Thanks in advance.

[earthwormjim]

I don't think you realize how loud 50W can be when talking component speakers, let alone 75W. That amplifier should be better than what is in your head unit, so use the amp to drive all your speakers. There's no way your head unit is realistically going to match 50W on the back channels anyway. The power ratings on headunits are a joke.

[Gregs///M]

I agree with Jim too. Powering all four may be the best bet. However, in the end, its all personal taste. For me, I am not too fond of loud rear speakers, I keep the gain on mine barely audible and my front stage gets most of the volume. Therefore, if its your personal preference to lower the output of your rears, then use the amp for the front only.

[bmwman91]

Head units can only really deliver ~15W-RMS before distortion shoots through the double-digit percentages. Their amplifier IC's are running on Vbatt, and the "50Wx4" figure is really BS. It is what you get running 14VDC into a 4 Ohm resistor, and by the time the output is within 1-2V of one of the rails it is going to be pretty nonlinear and highly distorted. Hence the reason why an aftermarket amplifier that also delivers "50W" per channel is physically huge...it has a switchmode or boost converter to provide a >34V supply to get a real RMS 50W output.

Anyway, as the guys above said, 50W of true RMS output is a lot with any halfway decent speaker. A reasonable mid-range or full-range driver should have a sensitivity of ~90dB at 1W, so 50W would have you at ~107dB from that speaker. Two of those would mean 110dB sound pressure...more than enough for most people.