What size amp will I need?

Question

I have 2 450 watt 6x9 speakers and a 600 watt sub that I plan on getting Installed into my car but I am not sure what sized amp I will need to power them. Is there a correct size or is the more power the better?

Answer 1

Eric is very wrong, in that he explains that you need to go by the Peak Watts rather than the RMS Watts.



You must always match the RMS Watts to the amplifier accordingly, and not the Peak Watts.

Don't even take the Peak Watts into consideration when spec'ing your amplifier.



Those values you've given us to use, are pretty likely the Peak Watts.

So, by using them as a reference, you can kind of guess that the 6x9 speakers are of around 120wRMS, and the sub-woofer around 200wRMS. You'll really need to check this, but we'll use it as a guide for now.



I'd recommend getting 2 amplifiers in total.

You'd need a 2 channel amplifier to run the 6"x9" speakers, the specs on this would be something like 120wRMS x2 @4ohm.



You'd then need a mono-block amplifier that will run the sub-woofer.

This is a bit more tricky, because you have several options for the ohms rating (impedance).

If it's a 4ohm DVC, this means it has 2 voice coils both having a 4ohm impedance. Your options are either 2ohm or 8ohm. 2ohm is the most common with regard to compatibility with amplifiers.

If it's a 4ohm SVC, this means it has only one voice coil having 4ohm impedance and your only option is 4ohms in this case.



Now, for a mono-block amplifier you need something like 200wRMS @2ohms, or 4ohms.



As for 'more power, the better', it is alright in some circumstances, but not this time.



Good luck!

Answer 2

You don''t want to amp your back speakers before you amp your fronts. you don't hear 6x9 in the rear over your front speakers and the only reason they are there is for back-fill and a little bit of midbass, thats it. 600w im guessing is peak power, so you need a 300w amp or less. Same thing goes with speakers, RMS is what you want to power at, not peak.

If you need clarification as to why I say that then read this:

http://www.crutchfield.com/S-E79cnI9hWw3/learn/reviews/20030722/subwoofer_power.html

Answer 3

most likey you can hook up the 6x9s directly to the stereo as it should push them just fine. you want to look at the peak wattage of the sub and buy an amp accordingly, not the rms wattage. if you cant find the peak wattage of the sub, then going by rms (600 watts) is ok. oh and you only need a mono amp if your only going to hook up 1 sub.