MKV - Slowing file down?

[coyttl]

Hey all -
Happy Turkey Day for those in the US.

Have a question. Somehow, during an encode of a video file, the video and audio got sped up. i.e. It should be playing at 23.976, but both are sped up playing at 25fps.

To avoid re-encoding both files, is there a way I can re-mux them and slow the audio down?

What I've tried -
Using MKVMerge, specifying the framerate as 23.976 - this works fine. However, when I put in .95904xxx for the stretch (to slow it down, 23.976/25), it seems to stretch the audio a little too much. What should be the proper value for the audio in there? Or am I stuck and have to run the audio through a processor?

Cheers,
Mike.