how to bench test for watts

[enraged]

i think i got it right but can someone tell me how to figure true wattage,,,dont ya use test tones, and check with voltmeter on ac and probe the outputs on the amp while playing tones and square the number and then divide by ohms of subs?,,,,example 55 ac volts equals ?

[helotaxi]

You need to use a large bank of resistors that are wired to the load that you want to test at. You might want to have a way of cooling them as they are going to get really hot. You want to use resistors because there is no variance in the resistance based of frequency, there is no impedance phase shift and there is no risk of destroying your sub.

You will need a multimeter that measures RMS VAC and a 0 dB test tone. Play the tone at max with the gain properly set and measure the voltage across the resistor bank. Square the voltage and divide by the resistance.

[maylar]

You should also have an oscilloscope to verify that the amp isn't going into major distortion while doing the test.