Topic: Audacity matrix question and observation - syncing creates new peaks?

[Roving Sign]

I am syncing to 2 track sources together.

I notice that when I get the tracks perfectly synced, there are suddenly clips and peaks that aren't in either source...

If I mute each source - no clips, but together they clip...

Will Audacity prevent clipping when exporting? I'll answer that one...no...

Both individual recordings have plenty of headroom

Any workflow suggestions here?

It seems like I am getting some sort of additive reinforcement when the wavs sync up? (or is this just a bug in Audacity)

Do I actually have to reduce the volume of each source? (presuming I want to keep that ratio)

Maybe this is why Audacity has that -3db normalize preset...?

[Brian Skalinder]

It seems like I am getting some sort of additive reinforcement when the wavs sync up? (or is this just a bug in Audacity)

Don't think it's a bug.  Makes sense to me that summing two sources will produce a louder result.  Same thing happens for me in Audition/CEP and Samplitude SE.

Do I actually have to reduce the volume of each source? (presuming I want to keep that ratio)

Yes, just use the Gain slider for each track and adjust accordingly.

[gratefulphish]

Brian is right.  You are summing the two sources, and will end up with a much louder mix that either of the two sources separately.  As a simple example, I can see this on the output meters of an R-4 Pro, when I am recording four channels.  Although none of the channels are clipping, the summed channels shows clipping on the output meters.   As Brian indicated, you need to adjust the relative gain of each source, so that the result will not clip.  Best to copy a piece out of one of the loudest segments, paste it to a new file, and experiment with it there, until you find the levels you like, and ensure that it won't overload.

[BayTaynt3d]

This is also an excellent example of why when running 4 channels and knowing you're going to matrix them, you don't have to run your levels nearly as hot -- you not only leave yourself headroom in case it gets louder than you expected, but you also are less likely to have clipping when their summed (removing the need to digitally lower the volume of both before digitally summing them together). Combine this with 24-bit, and 4-channel allows you to leave yourself significant headroom with no downside.