i want to shift audio more precisely than possible i think. maybe audacity only works till 0,000 ?!
You have me baffled…
Why?
That’s 0,1 msec. Should be unnoticeable to any listener.
The smallest time unit for digital (PCM) audio is 1 sample period. If the sample rate is 44100 Samples per second, then 1 sample period is 1/44100 = 0.022675737 ms.
If you need greater resolution in the time domain, resample the audio to a higher sample rate (Tracks menu > Resample)
thank you very much steve 
right now i’m simply creating an acapella by phase cancellation method
but in the past i very often used one half of the frequency spectrum from one track and the upper/lower / other half of the frequency spectrum of an other track
thats how i created perfect mixes https://www.mixcloud.com/dnbTime/calibre/
turn out the acapella sounds much cleaner