Hi, I have an audio file that contains two songs playing at the same time. I also have a portion of one of the songs as a separate file. I put both tracks in audacity, but they were’n aligned correctly. How do I align them so I can invert one of them?
Yes but how do I find the right spot to move it to? I tried 9.5 seconds but it wasn’t quite right.
What are you trying to do?
To get cancellation you have to flip one of them over Effect > Invert. Then you painfully shift the cancellation track little bit by little bit until it cancels. You can sometimes select a very little portion of the show, shift one track and watch the blue waves line up. Sometimes in complex shows you just have to keep shifting it and listen until it works.
And it may never work. Cancellation is very tricky.
Koz
So would it be possible to write a plugin that would, e.g., open a sound file and find where that file starts in the audio track?
All files imported by Audacity import with the start of the audio data at zero, whether that data is silence or quiet noise.
Are you looking for where the song starts, after any silence or quiet noise?
What are you trying to do - remove vocals?
Gale
I’m working with a remix of a song, and the remix contains clips of the original song playing along with the remix. I’m trying to remove those clips.
https://forum.audacityteam.org/t/produce-an-acapella-song/32457/1
That’s all the steps in this posting. If you need any details, post back. (to this thread, not that one).
Koz
Looking at the spectrogram view , rather than waveform view , may make alignment easier, the matching patterns are more obvious.
The invert cancellation technique (destructive interference) will only work if the waveforms match perfectly,
IMO you’re going to have to use a spectral-subtraction method like Kn0ck0ut
where the timing and amplitude don’t have to match exactly ,
( however the results of Kn0ck0ut have digital processing artifacts 
).