Findinging out wattage with DMM

[mythyone 10+ year member]

I was watching some random u-tube videos and ran across one from ED and setting amps with a dmm. He set it to 40 volts and said that that was around 400 watts. I was wondering what type of power my amp is putting out on my electrical right now, and then see what it does after doing some upgrades. Is it as simple as they show in the vid, just hook it up to the pos and neg on your amp and play a tone around 50hz? Or is there a different Freq i should use to test it. Thanks //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

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[pjhabit 10+ year member]

Sq. Root of (Watts × Ohms) = Voltage

50Hz 0dB sine wave works good for subs

1kHz 0dB sine wave works good for fronts

 

[gunz4me 10+ year member]

Only problem is some of the lower cost digital meters will only read AC voltage in the 50 to 70 Hz range since that is the frequency that typical household AC voltage operates at. Make certain your digital multimeter can read 1,000 Hz before you start using it.

Also, do your voltage readings with the speakers disconnected from the amplifier and all processing disabled on the hu and amps. This means keep your bass flat, treble flat, no loudness enabled, no bass boost on your amp, and no crossovers enabled on your amplifiers. Keep in mind that this is just a test to get you in the ball park and you will still have to use your ear for the final tuning.

 

[mythyone 10+ year member]

Sq. Root of (Watts × Ohms) = Voltage
50Hz 0dB sine wave works good for subs

1kHz 0dB sine wave works good for fronts

Dam, im gonna have to do some Math ,So just plug in what i know find the missing link huh?

 

[JimJ 5,000+ posts]

I wouldn't trust what eD told me if they told me that the sky was blue.

 

[n2audio 5,000+ posts]

you can't do a max power test with a DMM. YOu can only measure voltage and calculate power at a level that you know is within the limitation of your amp.

 

[gunz4me 10+ year member]

True, you need an oscilloscope for that! I just wish mine wasn't the size of my 2000 watt Honda Generator.

 

[pjhabit 10+ year member]

Dam, im gonna have to do some Math ,So just plug in what i know find the missing link huh?

(the voltage squared) / Ohms = watts //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[jdawg 5,000+ posts]

use really long lead wires

 

[mythyone 10+ year member]

So would it be pointless to grab a dmm? Was gonna grab it cuz I wanted to see around how much power i added by upgrading my electrical . Im sure i could find other uses for it but this way one of my main ones.

 

[pjhabit 10+ year member]

So would it be pointless to grab a dmm? Was gonna grab it cuz I wanted to see around how much power i added by upgrading my electrical . Im sure i could find other uses for it but this way one of my main ones.

Though it won't tell you when you're clipping. It wouldn't be pointless, everyone into car audio should have one.

 

[mythyone 10+ year member]

Though it won't tell you when you're clipping. It wouldn't be pointless, everyone into car audio should have one.

Ah, i got the little remote thing to tell when im clipping , DJ from AQ talked me threw on setting my gains and what not.I just wanted to see what doing the big 3 and maybe adding a 2nd batt would do to the power the amp puts out.