amp for speakers and sub

[bradl79]

If i get a 4 channel amp and use front speakers and bridge the sub do the speakers and sub need to have the same rms. Also how far off can u go on the rms from speakers/sub and amp.

[zako]

Don't worry about matching amplifier output to speakers. For most speakers 50-80watts is enough, but having too much power is never a bad thing. It can only be good (less THD when driven hard, more head room for dynamics even if not playing very loud). Since you need to drive a subwoofer with the same amplifier, I'd say find an amplifier with as much output as you can find/afford. I'd recommend PPI P900.4. In bridged mode, it's rated for about 450watt RMS output. I have driven a subwoofer with it for some time. It has reasonable side, and never got hot.

[sjv13]

If i get a 4 channel amp and use front speakers and bridge the sub do the speakers and sub need to have the same rms. Also how far off can u go on the rms from speakers/sub and amp.

4 channel amps come with separate settings for channel 1&2 and 3&4. So your front speakers would go on channels 1&2 and would have the gain set a certain way. Then channels 3&4 would be bridged and have a certain gain setting for the sub. The two gains are completely independent of each other.

Like the other guy said, it's never bad too have an amp that is too powerful. You will just have to set the gains lower than you would on an amp that puts out less power. And if you do use an amp that can put out too much power, you will have better sound quality because it will not have to work as hard (so that means less THD (total harmonic distortion) and a better signal to noise ratio).

On the other hand, an amp that puts out not enough power to your speakers (say they are rated to take 75 rms and the amp does 55 rms to each channel) will be the limiting factor in your system and when you push it past it's limit it will clip the signal and ruin your speakers.

[bradl79]

ok so i want my rms on my amp to be more than my speakers, b/c i can then control the gain on the amp?