Hi Folks, I have the strangest issue that I cant sort out. I open a multi track midi file, created a default TTS1 instrument, select all the midi tracks, set their outputs to the TTS-1 and play the file no problems.
I now want to use a better bass sound, so I create a new SI-Bass Guitar instrument. I can open the SI-Bass Guitar GUI and click on the strings and hear the audio no problem and see the levels in the meters. I now drag the bass midi clip to the new SI-Bass track. At this stage I can still manually play the SI-Bass. As soon as I hit play the output from the SI-Bass Guitar disappears! I can see the midi notes being triggered in the midi view of the SI-Bass track but no sound (and no audio on the meters). At this point I have to reload a preset on the SI-Bass GUI to get the sound back, but it only works while the track is stopped until I press play again.
I can play the SI-Bass from an external midi keyboard no problem. If I leave the bass midi clip in it's original track and just point it's output at the SI-Bass Guitar, the exact same thing happens!
There are no tracks muted or soloed, I have turned off automation track reads on all tracks.
I've spent days on this now and am all out of ideas..... Any help please..
I can do a quick video if that helps?
Regards Simon

Did you open the midi track and SI-Bass separately (not opening it via - Insert Soft Synth). If yes, then you will need to set the midi track output to SI-Bass manually.
 

 
A better option is to open midi track and the soft synth at the same time via
Insert - Soft Synth (select VSTi) - check Simple Instrument Track and Synth Track Folder.

Make sure the notes in the PRV are triggering the correct Midi Channel.

This should be obvious, but make sure that the MIDI notes are in the correct range for the instruments.  If they're outside the realistic scope of the bass, they won't play.

If the notes are the the synths range, the problem is likely in the file. Third party MIDI files often have data at the beginning which shut down sfz engine synths. Either open the Event List and remove the data or enable "Do not intercept NRPNs" in plug-in properties.

My goodness! That's the best tip yet!!  Thanks a million scook, I've never looked closely at that dialog. I have been opening files in Cubase to edit out the unwanted data. 
But it does kind of suck that Sonar would hide simple things like this in impossible places. 
I work from time to time with download files to use as backing tracks and often tracks revert to original settings no matter what you do in Sonars instrument dialogs. And controllers for things like instrument effects. Just try shutting the reverb off on the BAss in tts-1 as example..no way. 
The data is never in the event list which to me is where it belongs. That is where you will find it in other DAWs. So I've just always used Cubase to strip this data from the file. 
 
There's always more than one way to do the same thing in Sonar. 
Changing the bass to the SI Bass is as simple as this.
 
Open the synth rack on the right of screenset 2.
Insert the SI Bass 
In the dialog the only box I check is "use single output" and "always ask" - all other are not checked. 
Now go to the track header of the midi bass track and point it's output to the SI Bass.
90% of the time you will need to transpose it up +12. 
 
I don't like using the sythns audio track to put a midi track for a few reasons, just my way of working, we all work differently. 
One main reason is I might insert a few synths and then I can audition the midi track with different sound by simply changing the output. 
I also might point the output of more than one track at a certain instrument. 
to me everything is layed out logicialy if midi is in a midi track
audio in an audio track  and the synths are sitting there out of sight. I put all synth tracks at the top grouped to gether. 
It's great that we have all these options for workflow 'cause we all think differently. 
 
 
 

Cactus Music
My goodness! That's the best tip yet!!  Thanks a million scook, . 

Steve is such a show off
 
Have you ever gotten advise from someone on here and been like " I don't know about this".
I never get that feeling with Steve. when he gives a solution its typically right on.
I also say the same for you Johnny. your also a very knowledgeable gentlemen. 
A lot of great people on this forum. probably the fastest turn around on the internet.

To the OP:
 
it may possibly be your Inputs/Outputs this is target for drums but its basic midi I/O:
https://www.youtube.com/watch?v=k83UVo1OiKA
 
Also, I believe you were asking a while back about using an Alesis SR 16 in Sonar.
here's a video on how to do that:
https://www.youtube.com/watch?v=TjZS61Wg-XY
 
not sure if any of this will help but add it to the pile of possible solutions.
because there are a few and mine probably is not one of them

Cactus Music
The data is never in the event list which to me is where it belongs. That is where you will find it in other DAWs.

 
Initial values of Volume, Pan, Bank and Patch events will get pulled into the corresponding track header fields on loading. Otherwise, all controllers should show in the Event list by default, including RPN/NRPN events, unless you've unchecked the option to show that 'Kind' of event.

Thanks Chuck, you are too are very helpful.
Dave I've tried every option I could find with that event list and gave up. Yes I do see what happens in Sonar to certain events but it's always been frustrating to me that the event list is different than other DAWs. To me even if it is somewhere else that list should show every possible bit of data lurking in a mid file. I'm just old school and after living with my Dr T's event list as my only editing option for ??? years I'm slow to learn new fangled ideas like piano roll :)