I'm not sure where you stand as far as electrical theory in your background. If this seems overly simple please forgive me - I'm just trying to offer a complete explaination.

Scott is correct in that you would have N x 2 watts AVAILABLE, however that would not really be delivered.

Watts are computed by multiplying amps by volts. So an 8v RMS sine wave into an 8 ohm impedence would drive one ampere, resulting in an 8 watt power disipation across the load.

Amplifiers are a voltage source - the output voltage is designed to be a magnified version of the input voltage instant by instant. They are also capable of supplying a relatively large amount of current, but the actual current draw is not controlled tightly by the amp. The load is allowed to draw whatever it needs at the currently applied voltage, instant by instant.

A speakers impedence will not be altered by your amplifier.

If a uniformly distributed (noise) signal is used as an example, and it is driven into a speaker with a crossover that splits the current (and power) in half, and the overall speaker impedence with this signal is 8 ohms, then under these conditions each half of the speaker is exhibiting a 16 ohm impedence. If the speaker inputs are split between two amps each amp (all else not changed) would see a 16 ohm effective load. Total power available to this system would be whatever the amps can deliver into 16 ohms (NOT 8) x 2.

So you may get a bit more power, but I doubt it would be much, as most amps are optimized to drive loads 8 ohms and below.

[This message has been edited by charlie (edited September 11, 2002).]