# stretch/compact audio accurately

TL;DR version:
I need to make 28.5525minute audio track become 28.54083, but the “change speed” effect can’t be accurate enough (99.95914% became 99.9% when tried)

Long story:
I have two ~28.5 minute audio tracks that need to be combined. Both tracks just have voice. Thing is, there is some cross-talk with the mics, so one is picking up my voice along with a little bit of the other voice, and vice-versa. this shouldn’t be a problem after combining the both tracks into one (I do want both voices in one final track.), but the second audio track doesn’t sync up properly with the first. for example, the first audio track is 28min 32.45sec(28.5408333min), but the other is 28min 33.15sec(28.5525min) (.7 second difference). The difference is enough to have a noticeable echo after about 2 minutes into the audio. After 20 minutes, I’m answering qustions that havn’t finished being asked.
I noticed the change speed effect, but this deals with percentage, so I’d need 99.95914% tempo. first I tried putting in 99.959, but I figured out it wants decimal form… so I put in 0.99959. It seemed to use something like 0.99 instead. so the echo is worse.

P.s. It’s 2am, so if my explanations are bad, I’ll clarify tomorrow.

To calculate the necessary percentage:

The ratio is:
(“old duration” - “new duration”) / “new duration”

(28.5525 - 28.54083) / 28.54083
= 0.01167 / 28.54083
= 0.000408888

To convert the ratio in a percentage, multiply by 100
0.000408888 x 100 = 0.0408888

Copy and paste that into the change speed effect and the result will be 28 mins 32.450 seconds = 28.540833333 minutes (an error of 0.2 milliseconds)