I'm sure this has been covered, but I have not been able to find it anywhere here. I am writing a piece for a Winter Guard group I work for, and anytime I playback the score the rhythms are uneven and sound inconsistent. When I highlight a specific part (say Snareline Manual LITE (A)) the rhythms are still not truly accurate. When I export the score audio, however, this problem is fixed, and all rhythms playback true.
I run: Mac OSX ver. 10.7.2 --3.4GHz Intel Core i7 --Memory: 8GB 1333MHz DDR3 Sibelius 7.0.3 Kontakt 4.2.4 VDL 2.5.2
The buffer size is 1024, and the sample rate is 44.1.
Have you tried setting Sibelius 7 to launch in 32bit mode? You can do this by quitting the application, going to its ";Get info"; window, and clicking the ";Open in 32bit mode"; checkbox. Let us know if you see any differing results after trying that.