Hello,
 
I'm getting nasty pops and clicks when starting and stopping playback in sonar using the spacebar on the pc keyboard. I'm just using two virtual instruments; Addictive Drums 2 and SI Bass. Any tips greatly appreciated.
 
Thanks,
 
-Warren

See Fade On Start/Stop settings in Preferences > Audio > Playback and Recording. Careful with Fade On Start, though as it can 'eat' percussive attacks, making you think something is out of whack with synth rendering. A few milliseconds is usually all it takes to smooth things out if this is the cause.

Thanks brundlefly! I followed your suggestion; worked like a charm! Now I am enjoying super smooth playback in Sonar. THANKS!!!

Tried this and it didn't help in my case. Still clicks and pops.