How to change the Audio speed without changing the duration

are you talking about changing the speed without changing the pitch?  Thats an option in the speed dialog.  Premiere doesn't always do the best quality possible on this.  I usually open the file in audition to do this although the interface is different than within Premiere and can make things complicated...

I do not know if Premiere Pro can handle mixed sample rates (I seriously doubt it can) but by far & away the best way is to change thesample rate but leave the project SR the same.

So for example at a sample rate of 48k, you play out at 48,000 samples per second. To slow this down you need to have the audio at a higher sample rate - so to slow it down by 10% you need to resample the audio by upsampling from 48,000 + approx 4,800 (you will need to work this out properly as upsampling by 10% will cause more than a 10% slowdown of course). Then render the upsampled audio out at the original sample rate. This will slow it down.

Best of all, you will simply not get any nasty time stretching algorithm artifacts.

Audition or your regular DAW is the best way to pull this off, and then re-import the resulting audio file back into premiere

If you have a video track with '100 beats' and an audio track, the same length with '110 beats' you slow the audio down so the first 100 beats match you have 10 beats of audio left over. I would edit the track to lose those 10 extra beats.

I might be missing something here if yt can do it.

I must be missing something...how can slower not take more time?

Hi @Prakriti.90 ,

If you wish to change the audio speed independently of the video, which will maintain you clip length, you can Unliink the video from the Audio from the Video. The video will maintain your track length while you manipulate your audio. 

You may also find this helpful. https://helpx.adobe.com/uk/premiere-pro/using/remix-stretch-audio-audition-premiere-pro-directlink.html

Let us know ho you go.

mj

If you slow down the track it will get longer.