It's just happened using a song with the TWO_BEAT.STY style. The first beat was almost silent then the rest was OK.

Looking at the audio edit window, the drums all look OK and if I play again from there it sounds fine. It normally sounds OK on the second time of playing anyway.

I am using the MME driver. I can try changing, but as it doesn't always happen I'm not sure how easy it will be to tell if it's made any difference.

Thanks for the suggestions.

Andy