Oh!
BTW--I did try using Layers -- putting one instrument into Layer 1, and the other into Layer2.
I also tried using an Expression to change the channel from one to the other.

In both cases, when the tremolo played back it also made a scraping, almost "chirping," sound along with the tremolo.

When only the GPO Solo Strings Viola Solo KS was used the tremolo playback was smooth.

:-)
Vanessa

I find I usually return to the GPO4 set for my string sounds under normal circumstances. There is something about the GPO5 set; perhaps they are better suited for more specialized use.

Thank you, Adrian,

I am beginning to notice the same.

Some seem to respond in playback better than others.
Sometimes, I notice a passage becomes suddenly subdued. For some reason I tried adding a dynamic Expression where this occurs, and then deselect the "Show" (right-click on the Expression) and that--for whatever reason--ensures continuity of dynamics.

For example, in an 8-bar phrase marked "mf," bars 1-3 will play back correctly, but bars 4-8 might become "mp."
So, at bar #4 I reintroduce the "mf" and turn off "Show," and the dynamic level remains; sort of like a booster shot ;-)

:-)
Vanessa