Hello everyone I’m new on this forum, I’m a 12 years old french so sorry for my very bad english. 
I’m begin with audacity and I have some problems with the mixing. I have create three different instrumental classical instrument tracks directly on the computer with Musescore. Separately on Audacity they are clear and clean but when I’m superposing the tracks, the piece become illegible with very disturbing and unpleasant sizzle during all the piece. I don’t now why that do that, if my computer is too weak for that or if that we can resolve that with settings. If someone can help me, that would be great because that blocked me in my creation process.
Thank you so much !
I’d guess you’re getting [u]clipping[/u]. Mixing is done by summation and the sum of 2 or more tracks will often clip.
FYI - Analog mixers are built-around summing amplifiers, but analog mixers have a volume fader for each input plus a master fader.
The easiest solution is to export to floating-point WAV which essentially has no upper limit .* Then re-open the mixed file and use the Normalize or Amplify effect to bring the levels down to a safe level.
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- If you have a floating-point file and you play it at full-digital volume you’ll clip your analog converter.