How To Properly Set Amp Gains With A O-Scope AND By Ear

The number 1 most misunderstood adjustment in car audio is setting the gains on amplifiers. The gain knob is NOT a volume knob, instead it is for level matching, to match the output voltage of the head unit. The correct way to do this is with an oscilliscope.

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Moreover, most head units do not put out a clean signal all the way to the top of the volume knob, especially on the internal power side. Many people believe that you set gains by setting the head unit at 75% volume, but Jefferson shows you why that is not a good plan, as even a high-end Alpine head unit clips the signal BEFORE 75%.

For our tests, we have an Alpine head unit from 2003, a Pioneer 2-channel amp from the same era, and a couple of speaker pods. We are using a 1khx sine wave test tone. You don't want to use music for this test, it is too dynamic and you won't be able to see the actual signal on the scope.

We do play the test tone on the speakers, which is very loud, so be prepared for that in the middle of the video.