The only sound file that is not a headache to work with is mp3. some browsers like firefox can be really picky about ‘encoding’ of the sound files or their bit rates. As for ‘previewing’ but not being able to play in the experiment is probably due to preview is using a different decoding then the experiment one. If you really need to use wav files, you can re-export them as 16-bit PCM, 44100 Hz.You can easily do that with the command line tool ffmpeg. go to the folder that all sound files exist, and run the following command:
for f in *.wav; do ffmpeg -i “$f” -acodec pcm_s16le -ar 44100 “${f%.wav}_16.wav”; done