Wow! Sundown Ftmfw

[Derrick824]

so how does it work?

does the speakers have to be hooked up for the ohm load?

David already explained it.

without a true rms clamp meter ur not getting the correct info.

you need to factor in amperage to get the correct true number.

The square root voltage method is a very rough estimate. It assumes that you're seeing an equal output in amperage as you are voltage which is rarely the case especially when running at 1ohm or higher.

[crf450r4u2nv]

wouldn't volt x amps = watts

work in all cases regardless of ohms

of coarse with rms dmm's

[sundownz]

wouldn't volt x amps = watts

work in all cases regardless of ohms

of coarse with rms dmm's

Roughly - you have power factor in a reactive load... but to compare to other "clamped" figures if you have true RMS meters and use voltage x current you can compare. You also need to take the measurements at the SAME TIME as voltage and current don't peak together - if you take peak hold on both meters the number is wrong too.

I just use an Extech True Power meter that just pits out kw figures for me

[Nightshade]

With a load on my subs I consistantly get 54.3 volts and 28.5 amps at 40hz which equals 1547 watts after rise. The actual rise is 1.9 ohms there. But at 48hz these are my figures 48.9 volts and 36.8 amps which is 1799 watts after rise. The impedence rise is 1.32 ohms.

These tests are done with a true rms meter which is a Fluke but I can't remember the model number. The amp's nominal impedence is .5 ohms and you can see that it still makes a ton of power after rise. I really can't say if the amps are clipping of not either cause I've never had them on a scope, but they don't get hot at all and I've never had a problem with any of the voice coils on any of my subs so I'll assume that they aren't clipping.