Hello Free Trial!
Here are some hints how you can optimize the playback.
1. If you get a grace note like sound at a transition, you might want to shorten the preceding note as explained in the "Optimizing Sibelius Playback" manual, page 19. In general I recommend working with the Sibelius Inspector in order to get the best out of the playback.
2. This can have different reasons. First I would check, if it helps setting the Sibelius playback performance settings to "meccanico". Anyway it's true that the attack times of the staccato repetitions are not equal. To get the rhythm straighter, you can trigger the short notes/staccato (non repetition) patch in one of the custom cells. How to do that is explained in the "Optimizing Sibelius Playback" manual, page 12.
3. I guess you are talking about the sustain patch here, right? Please note that this patch includes single notes which will not work that good for phrases in most cases. A slow attack is only natural for single (or starting) notes in string groups. You might want to try legato or for shorter notes detache instead.
Best regards,
Andi
Vienna Symphonic Library