I used Audacity to “Split Stereo Track”; made some adjustments to one of the tracks, and then “Make Stereo Track” to turn it back to normal stereo. But when I Export this as MP3, although it plays quite happily in all the ‘on-line’ players (eg. Windows Media Player) it won’t play in Yamaha keyboards eg. Tyros 4, which normally will play any MP3. The message I get in my keyboard says “This data format is not supported”. Any ideas what is going on here? When importing a WAV file into Audacity and Exporting it as MP3 it plays fine in my Tyros 4. It’s just after that process of splitting the stereo track into two, and then combining them again as one that I get the problem of it not playing.