One of my projects has suddenly developed an intermittent distortion. On playback it occassionally produces a loud and ugly static type distortion sound. I'm not sure whether it is specific to certain individual / specific channels or is across the master. I've been working on the track for some time and seem to remember having some trouble tracking the bass guitar initially as I was experiencing some less aggresive distortion then also. My bass is active so I presumed the battery may have been running down at the time and causing the problem. I changed the battery and it seemed to clear. However, I thought I could still detect a subtle distortion on the bass track but wasn't sure if I was imagining it or not. The real big and obvious distortion has only happened once and, as I say, was on playback. This was quite some time after the initial problem I encountered when tracking the bass and there had been no problems for quite some time in between the two events. There is quite a lot going on on the project but CPU is only pushing 50% or so at peaks. Also, there was very little on the project at the time when the bass guitar was tracked and the initial distortion was noted. After the heavy distortion on playback event I immediately closed the project without saving and re-opened. The distortion had then gone! I've been working on Logic Pro 9 for a couple of years and never had this problem before. Any ideas.