I need some audio help. how do i know how many watts speakers i can power off of an amp? or vice versa? ?

Most normal stereo amplifiers can handle a 4 ohm load on each side. That would be two 8 ohm speakers on each side for a total of 4 speakers. You really need to read the owners manual for your amp. It should explain how many speakers the amp can handle. A 1000 watt amp cannot handle 1000 one watt speakers. It does not work that way. I would recommend reading up on speakers and amplifiers (ohms, impedance matching etc). There are some great books and some good info online: http://www.bcae1.com/spkrmlti.htm http://www.prestonelectronics.com/audio/Impedance.htm The watts you need will depend on many factors including your room size, the type of music, your speaker's sensitivity etc.

In general, if you want to use a power amp (As opposed to a home theater receiver) to run more than one pair of speakers, then you need a power amp that is built to run more than one pair of speakers. Its not just wattages, but it's also a matter of impedances. Most speakers have an 8 ohm load, and if you hook two speakers to one speaker output, you will cut that in half, and could damage both the speakers and the amp. There are power amps that can power more than one pair of speakers, if you want such a capability, buy an amp that is built to do this. Also, in general, when matching up the max power ratings of an amp and speakers, its useful to get speakers whose top limit is not less than the power output top limit on the amp.

It depends how much you are willing to spend, and what you are using it for, $100-$1000, home or professional use. Lets say speakers are 100 watts RMS. It's best to have an amplifier that has 200 RMS, and only run the amp at half power (100 watts) so clipped signals won't blow the amp. If you are really serious you'd get a 400watt RMS amp, so even the peak transients wouldn't be distorted and clean power would go to the speaker. always get a more powerful amplifier if you can, and don't run the amp to 0db (full power), run it at -3db in this case (half power). and -6db in the 400 RMS case(fourth of the power) If you can't afford the more powerful amplifier, make sure you don't clip the little amplifier and drive it above 0db, or speakers will fry sooner or later.