Hi Marius, Thanks for checking it out, pinning this problem down will help others avoid it in the future. The fact that it's phasey suggests there are time offset problems. Constant phasing pitch is a constant offset, varying phasing would be a varying offset... How did playback sound when you were running the bounce? Was that satisfactory or inferior? Am I right in reading that the bounce & comparison recording were both made on the same pass? What audio hardware are you running Logic with? And what EQ & effects are involved? It is possible that some effects like eg Chorus might have their LFOs at different phases on successive passes. Another possibility is that the bounce might be slightly offset in time, out of sync compared with the actual analog & digital outputs from your hardware. If you trim both up to the first transient with sample accuracy, thus re-syncing the two, they would then compare identically. Any other ideas on what might be wrong? Cheers, Thomas