I have been having issues with VSTs producing sound. My setup was working then stopped. I reinstalled Sonar X3 Producer up to X3d. I have a midi track. I insert TTS-1 and assign midi output to it. Works fine. I insert SI-Drumkit, click on the drums and get sound. I assign midi track output to the SI-Drumkit and get no sound. Open the SI-drumkit properties and no longer get sound when I click on the drums. My system was working great until a couple weeks ago. No changes now it doesn't work. (And Lost Session Drummer 3 in the reinstall)
 
Very frustrated.

Not sure what inspired the re-install, but that should be done only as a last resort as some problems are transitory. For example I had a problem once with Sonar where restarting the computer didn't solve it, so I figured there was a problem with the software. As luck would have it, I had to leave and postpone dealing with whatever the problem was, and it turned out that turning off power to the computer completely and turning it back on again later solved the problem. It was some computer issue that was affecting Sonar.
 
That said, is it ALL VSTs that don't work, or only SI Drums?

Well it started with losing Session Drummer 3 which is what I usually use. First it was happening with that. Dimension Pro does not work either. Addictive Drums does work. It just seems to be that the MIDI won't output to SI and DP. I have not tried other synths yet. As I don't really use other ones.

I have no idea how MIDI data can decide to feed one instrument but not another. Is this during playback of MIDI data, when trying to trigger from a MIDI controller, or both? The MIDI track feeding the instrument needs to have the focus. Perhaps you've clicked somewhere else and it has lost focus?

It works when triggering from controller when I first insert synth. Then when I play MIDI data, no sound and then controller no longer works.

Sounds like the MIDI track might be sending controller 7 = 0 and turning off the volume. Try this: just before the first MIDI note in the track occurs, enter a controller 7 value of 127 and see what happens.

How do I enter the controller value?

Ok, so now I'm really frustrated. I created a brand new file based on the normal template. I inserted the DP 1.5 Synth with a MIDI source track and a synth track. When I hit the keys on my controller I see the audio meters for the midi track show activity. But no sound, and nothing on the synth track audio meter. I have tried the SI Bass, SI Drums, DP 1.5, and Addictive Drums, and TTS-1 ... AD and TTS-1 works. Nothing else!!! Please help what is wrong here?

Ok, I just recreated a file from the normal template. I inserted the DP 1.5 instrument with just a Simple Instrument track. Then inserted a MIDI track manually. This all seems to work. So my original problem seems to have something to do with the midi sequences that I'm using. I started with a midi sequence and removed all events except notes. And still get no sound from it. Any ideas?

jdenio
How do I enter the controller value?

There are a couple ways to do this. Probably the easiest is to open the strip at the bottom of piano roll view. Select controller 7. Use the pencil tool and click a little past the beginning at the highest possible level in the strip. You can also use the event list and enter a controller 7 value there.