Windows 10, Audacity 2.4.2
How do I move a track more precisely with the Time Shift Tool? I need it so I can do the phase invert thingy and mute the acapella. It’s hard to explain but I’ll attach an image to make it more clear.
In the first image, I need that red line to align the green one, but as soon as I move the upper track a little bit, it is way too much and doesn’t align properly.
I know this might be hard to understand, sorry for that, I’m a newbie.
The Time Shift tool always moves clips by an exact number of samples.
To move a clip by a fractional sample distance you will need to cut and paste it.
Note that the length of a sample period depends on the track sample rate. In the case of your screenshots, one track has a sample rate of 48000 and the other has a sample rate of 44100, so most of the samples in one track will not align with samples in the other.
You can use Tracks → Resample to change one of the sample rates.
But different sample rates means they are probably different recordings and if they are different recordings what you’re trying to do won’t work. 
…Usually the only way you have files that will subtract is if you made the recording yourself. And even if you made the recording & mix yourself you might have changed the volume (or something else) during mixing and this makes it “difficult”.
The recordings have to be “exact”. For example, if you record yourself saying “hello”, make a copy, invert one copy and mix, you’ll get total silence. But if you make two separate recordings, subtraction just makes a normal mix and subtraction sounds exactly like addition.
Thanks guys 