Comments on Profile Post by philipmorgan

That's what I did. Put my multimeter in Vac mode and use P=V^2/R. Note that I am assuming that R is constant across the frequency spectrum.

What kind of test tone did you use? Would measuring speaker R help? Possible to do that at a specific frequency with something simple like a multimeter?

If you want to be completely accurate, you need two multimeters. One to measure current and one to measure voltage. Then do P=IV. You might also be able to add a 1 ohm resistor to the output and measure the voltage across it to get the current.

The R of the of speaker is in DC so not completely accurate. I just go by the spec sheet impedance. I use this website to generate a tone.

http://www.szynalski.com/tone-generator/

I normally do 500Hz or 1000Hz

Dude, thank you! Will give that a try

When you want reliable results (esp in case of high mech Q bass drivers with some impedance swing) you'd be better of with scope than DMMs. A current probe inline (just a resistor can do), voltage across it and voltage bw terminals. You need two channels. Then you can get phase difference out and calc real and reactive power in each freq point.

When using scope be sure that the amp output is either truly floating or (-) is ground referenced, where you connect your probe ground. Otherwise: white smoke!

I think I’ll try a DMM for now, but a picoscope is in the horizon. Hopefully without white smoke :)