Can too few asio buffers cause midi problems?

Generally, if Sonar insists on hanging out after being closed - it is waiting for something to be freed up, and many times that will be because BitBridge is running in the background (BitBridge is launched automatically when Sonar loads a 32-bit plugin into a given project, and acts as a bridging mechanism to allow 32-bit plugins to run in a 64-bit Sonar environment).
 
So - if you see BitBridge running in Task Manager, after shutting down Sonar, you can force-terminate BitBridge.
 
I think also that some folks get Sonar to quit running after being closed, by powering down or disconnecting their audio interface.
 
So - neither of the above is difficult or time consuming to try out - I hope one of them works for you.
 
Bob Bone
 

I'm not aware of any interaction between live MIDI input and ASIO buffer size. Re-starting SONAR will probably solve the problem, but if it happens again, start by splitting the Instrument track to see whether the problem is MIDI or audio.
 
If the synth has a virtual keyboard/controller or patch audition function, see if it generates output that way. If the audio engine didn't drop out completely when you lowered the buffer and audio track playback is working, you should be able to get output from the the synth directly.
 
If the audio side is working and the MIDI track is echoing input but the synth isn't responding, the most likely causes would be:
 
1. The synth is set to respond to a specific channel that doesn't match what your controller is sending.
 
2. The notes are outside the restricted range of the patch.
 
3. Some CC message has zeroed the output level (e.g. CC1=0 sent when Zero Controllers When Playback Stops is enabled in preferences will silence Garritan/ARIA Player).
 
4. The patch has an extremely slow attack (possibly increased by an errant CC73 message) such that short duration notes don't reach an audible level (unlikely, but it has been known to happen).