wetdentist
maybe the note values in the sequence don't match up with the note values of the drums in the module. maybe try selecting all the note values in the sequence and move them up or down. maybe worth a try

Tried that, too.  Nope.

robert_e_bone
Since you can hear the drums on preview, it sounds like as noted above a channel issue.
 
Just under the FX Bin on the midi track, try setting the Output Midi Channel to channel 10, AND look at the midi channel setting for whatever synth you are trying to use to play the drum events through.  The accepted normal channel for drums is midi channel 10.
 
You can highlight the midi track and click View>Event List, to see the midi channel that was recorded for the drum events on the track, if you would prefer, then make sure you set your drum module to that same channel.
 
Bob Bone
 

Had done all that, just did it all again.  The MIDI track is set to channel 10 and the synth track is set to channel 10.
 

Loptec
does this happen with all your projects or is it just this one with the already sequenced drum track?

Since I upgraded to X2a a couple of months ago, I have only worked MIDI files in two songs.  One was just two weeks ago.  It worked fine.  I always bounce MIDI files to audio as soon as I have the sound and performance I want, then I delete the synth track, Archive and hide the MIDI track.
 
I went back to the song I was working two weeks ago, pulled up the drums track and bass track, un-archived them, applied SI Drum track to the first and Dimension Pro to the bass, but they will not work. 
 
Then I deleted the two synth tracks and SI Drums and Dimension Pro in the Synth Rack, add TTS-1, and both the bass and drum tracks work fine.

The fact that TTS-1 works fine, and none of the others should be telling me something, but I have no idea what.
It would make more sense if no synths worked, but TTS-1 does.  Damn.  I'm dead in the water.

OK - silly question, but did you change the Input to your audio track to pick up the OUTPUT from the new drum module?  You indicated you were using TTS-1, and when you change the midi track to point to a different synth, you then also need to switch the audio track(s) to also point to the new synth.
 
Bob Bone

Load (2nd) SI-Drums from the Browser (audio+MIDI) and record something in the newly created MIDI track just to make sure it works fine. Then delete this clip and drag the original drum clip(s) from the original MIDI track. If you hear the drums right (make sure it's in the right ocave), then you can delete the first SI-Drums from the Synth Rack (and the associated tracks) and you're all right. But if you want to find out what was causing the problem, before deleting the synth and the tracks you might want to widen the track strips as wide as possible and select "All" from the Track Control pulldown and then compare each option selected on the two MIDI tracks' strips.

What version of Windows? 32 or 64 bit?

Are you sure the audio engine is on?  Sometimes when the buffer is set too low....this will happen and you have to either up your buffer setting or turn the audio engine back on up on the toolbar.

I'd still check to confirm the output of the MIDI track...this should be something really simple.  I just took a blank project and put in a MIDI track, then added a single VSTi after that.  The output of the MIDI track did not go to the VSTi even though it was the only one there.

Dan Barnes
 

doncolga
Is your sequenced MIDI drum track set to output to other VST's?  That would do what you're describing.
 
Donny
 
 
There is only one VST in the Synth Rack, so can't be that.

The TTS-1 is the only multi-timbral softsynth that comes with Sonar. For all other softsynths, you have to load a separate instance of it to have it play more than one instrument sound.