I have SF 18 and windows 11; all of a sudden the music playback is slow and fuzzy; I have reinstalled the program and looked for updates, but it did not help.
Try resetting Sound Forge and clearing the cache. "File> "Reset all preferences and clear cached data". You could also try a different playback device in "Options> Preferences> Audio". MS Sound Mapper, and Windows Classic Wave Driver are usually trouble-free.