Audio player that can adjust playing speed
Solution 1:
The VLC media player is probably best suited.
It is Free
It plays .wav (and almost 100% of anything else out there)
It shows the Playback Speed settings.
- It allows speed setting as fine as 0.04 X increments.
Solution 2:
You can use -r to change the playback rate with afplay:
afplay -r 1.1 file.wav