Yes, you need to ensure both the MP3 and the .wav are exactly the same in volume and where the play back is from or you will get the sound of phasing and volume imbalance skewing the result. The easiest way to get the start lined up is to go to the first transient on both tracks and line them up.

The term used by Audacity to reverse the “polarity” of a track is to “invert” it. That is the option under effects.

So basically what you are doing is putting the tracks 180 degrees out of phase. If both tracks were exactly the same the result will be zero output. Usually even what you are left with (assuming MP3@320kbps and .wav) you’d need to amplify a fair bit to hear.

Tony

Last edited by Teunis; 05/14/19 05:20 PM.
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