I have met this problem before and it is related to Kernel parameter setting.
I have read somewhere that the best solution would be to recompile the Kernel which is probably too challenging operation for me who is new in Linux.
When starting the Rosegarden (midi sequencer) I get the following error message. Everything seems to work but no tone comes out.

Code:
Rosegarden was unable to find a high-resolution timing source for MIDI performance.
You may be able to solve this problem by loading the RTC timer kernel module. To do this, try running sudo modprobe snd-rtctimer in a terminal window and then restarting Rosegarden.
Br
Leevi