S5 - Suggestion
Each instrument sound is better than musescore 1.3 but the sound needs some improvement after half of a second of the sound start it gets a nasty growl on some instruments the sound of the brass start growling and has a high pitched ring after half a second when a note plays.
Are you talking tuba (and other low brass that uses that same sample)? There was a known issue with that in the beta - see #34151: Noise inside tuba sound.
If you are talking about something else, please post a score demonstrating the problem and describe how to reproduce it.
Here's a small showcase of bugged/improperly working instruments.
Tremolo strings - an unpleasant lagging effect lasting longer than the note itself
Distortion guitar - extremely quiet, practically can't be heard when other instruments are playing
Timpani - too quiet as well