How to change tempo to compensate for pitch change?

[Sucre]

Hello Audacity Forums;

First post.

I am changing the pitch of music in various places and then trying to figure out how to change the tempo of those same places to compensate for the change in length that occurs after I change the pitch. So far, no matter what calculations I do, it never works out. If I am doing this completely wrong, try not to laugh too hard

An example:

Track is 00:03:00.548 long

I change the pitch of section 00:00:00.000 to 00:00:01.900.

Doing so, changes the length of the entire track to 03:00.493, therefore it is now 00:00.065 shorter.

I assume then that the section I changed is what has been shortened so what was 00:00:00.000 to 00:00:01.900 is now in fact 00:00:00.000 to 00:01.835.

So I have been assuming that I could then select 00:00:00.000 to 00:01.835 and then change the tempo to make it again 00:00:00.000 to 00:00:01.900. I have tried both selecting the length of seconds from 1.84 to 1.90 and selecting a percent change of up to 10 decimal places (-3.4210526316). Doing either gives me a new track length of 00:03:00.548, that is out 00:00.010.

Thank you for any help.

[steve]

You are banging up against the limits of what the pitch / tempo stretching can do. These effects work by chopping up the sound into lots of little pieces, then splicing them back together again. The process is not 100% precise, so as you have discovered some minor discrepancies occur. In most situations accuracy is well within half a percent, which is close enough for most purposes but not necessarily for all. To get greater precision you will need mess about making little manual adjustments, or use a more specialised tool such as Acid Pro. (there may be other open source alternatives, but I usually resort to messing about with little manual adjustments, or using Adobe Audition).