Fixing sound files generated with Cepstral

If you generate a bunch of files with Cepstral, using default settings, you're probably going to be suprised when Asterisk doesn't play them. Even worse, sox will likely fail to recognize the file and refuse to transcode it.

The problem is that Asterisk is expecting an 8 kHz wav while Cepstral generates 16 kHz wavs (for most of its voices). You're faced with regenerating the files or transcoding them. Depending on the number of files, one method or the other will be preferable. I've put both methods in the wiki.