Upping my knowledge of digital sound a little, discovered “DSD” format which is fundamentally different from PCM. It’s a high resolution sound format used in PS3 and in some musical instruments.
There’s *one* free editor for DSD files, made by TASCAM. Called the “TASCAM Hi-Res Editor”, it’s free and edits DSD and WAV.
This page suggests using “foobar2000” to convert your MP3s, etc to WAV if you must, although several sites make a strong mention that there’s little point in decompressing MP3 and making it DSD because the compression in MP3 already removed significant signal, making it a bit of a waste of time and space to go from MP3 to DSD.
In any case, this is the stuff. This site has links to both the TASCAM Hi-Res Editor and foobar2000 (if you don’t already have foobar2000. I had it already but forgot as I usually use Audacity)