Okay, I tried PulseAudio and that didn't help.
I tried Daytona USA and that does not suffer from the problem! So, it looks like it could be something to do with the particular hardware for OutRun and Super Hang-On. They use similar hardware. I will look into it.
On a vaguely related issue, does anybody know why Magical Sound Shower sounds wrong out of VGMPlay and M1? I already know about the corrupted ROM shipped with the original game (see bottom of page: https://github.com/djyt/cannonball/wiki/Cannonball-Manual
). Compared to the CD releases and the song as heard inside MAME, Magical Sound Shower from VGMPlay and M1 sounds dull and lifeless.