scook
The only ways I know to route audio to a plug-in are the audio FX rack and side-chain input. There are synths which may be inserted into the FX rack and process audio but from your description above and the reply in the thread I linked, TX16wx does not appear to work that way.

I agree.  The sampler in the FX bin creates a dead-end for the signal path, until the FX is bypassed.  But then obviously you cannot record anything.
 
It's weird, because in Reaper, I can see that the sampler's receives are exposed in the "route" dialog and you can add any other available tracks in the DAW as receives to the sampler.  So it appears to be host dependent as far as routing goes.
 
To be clear, I'm not trying to start a Sonar vs. Reaper debate.  I'm just trying to better understand how Sonar works, and any necessary workarounds that I may need to know about.  I only keep Reaper on my system as a sanity check to test and compare plugins if something seems a bit off somewhere.

Aux tracks are new and can directly record audio from another track. If you have Sonar Platinum for 2016 you have those. Check out Patch Points and Aux Tracks in the help file.

John
Aux tracks are new and can directly record audio from another track. If you have Sonar Platinum for 2016 you have those. Check out Patch Points and Aux Tracks in the help file.

John, thanks for the tip!!!  Wilco.

I didn't go as far as patch point, but I did try it in an FX bin.  No dice.
 
I do have the freebie version though, and it has some dust on it.

BobF
I didn't go as far as patch point, but I did try it in an FX bin.  No dice.
 
I do have the freebie version though, and it has some dust on it.

Just gotta say, even if I have to drag n drop, it's still a pretty cool tool.  In addition to the keymapping, sound shaping with filters, envelopes, LFO's and modulation, the wave editor with looping and slicing gives it a lot of power.  For $32.36USD you can upgrade to the Pro version which has sample matrix triggering...

John
I would record to an aux track then bring those samples into the sampler. For a test try putting the sampler in the FX bin of the an aux track. 

Well I tried that and hit a dead-end again.  Must be some limitation related to an instrument track, or maybe I'm just brain farting today

I wouldn't use an instrument track. Aux tracks are not instrument tracks. 

John
I wouldn't use an instrument track. Aux tracks are not instrument tracks. 

Sorry, I phrased that comment inaccurately.  I was using an aux track.  My reference was to VSTi in general.  How do you access the return to a VSTi???

abacab

John
I wouldn't use an instrument track. Aux tracks are not instrument tracks. 

Sorry, I phrased that comment inaccurately.  I was using an aux track.  My reference was to VSTi in general.  How do you access the return to a VSTi???

I'm not sure I understand the question. Sorry. 

John

abacab

John
I wouldn't use an instrument track. Aux tracks are not instrument tracks. 

Sorry, I phrased that comment inaccurately.  I was using an aux track.  My reference was to VSTi in general.  How do you access the return to a VSTi???

I'm not sure I understand the question. Sorry. 

I guess perhaps that's because Sonar does not permit a return (audio input, does not exist?) to an instrument.  Effects only?