Bob,
 
When I bypass all effects I get sound when I play.  When I hit 'E' again to enable effects, I get no sound. I can toggle back and forth and I always get the same results. Maybe we're getting somewhere? 
 
Driver Mode: ASIO
ASIO Reported Latencies:
Input: 10.9 msec, 524 samples
Output: 16.8 msec, 808 samples
Total Roundtrip: 27.8 msec, 1332 samples
ASIO buffer size -- I couldn't find the value for this in my Tascam interface, but to the right of the Buffer Size slider (disabled) it says: 5.3 msec, 256 samples
 
Thanks,
Mike

With plugins enabled and no sound, when press Play is the Now Time marker moving forward along the timeline or stuck in place?
 

When the audio issues go away when the effects are all bypassed, it is a big clue that one or more of the effects that are loaded in the project are meant to be used for mixing and not for recording.
 
Some effects use something called 'look ahead processing' or otherwise chew up a bunch of CPU to do their thing, and these are designed for use once you begin mixing, because they really spike DPC latency.
 
I suppose one of the effects could also just be problematic, but the above is the usual explanation.
 
Please list all of the effects loaded into this particular project.
 
Bob Bone
 

Your latency values also seem about twice as high as what I end up with.
 
I run with an ASIO Buffer Size of 128 when recording (and 1024 when mixing).
 
That gives me the following reported values in Sonar:
Input: 4.9 msec, 215 samples
Output: 6.8 msec, 256 samples
Total Roundtrip: 11.6, 513 samples
 
What interface are you using?  Some audio interface control panels use a slider to adjust the buffer size, and may use a different term than ASIO Buffer Size.
 
Bob Bone
 
 

i went back for a quick cruise from the beginning of the thread.
 
Please list all loaded effects and soft-synths for this project.  
 
Thanks, 
 
Bob Bone
 

Actually those values are what would be expected for that interface etc. But what I'm reading into the latest update is that one of the effects is stopping your audio from reaching your master buss? 
Obviously you would now toggle each effect until you find the offender. 
This is sounding like a signal path issue. 

I'm using the following effects:
 
BlueTubes BrickWall BW2s-3 -- in the Pro Channel FX Chain for the Master buss
Three busses with Valhalla Room.
 
Btw, I've noticed that if I press play, then stop, then disable the effects ('E'), I hear the endings of the notes that were played. From my naive layman's perspective, it sounds like the sound is stuck when effects are on, and get unstuck when they're turned on.
 
I tried deleting all the effects from the busses, but still have to press 'E' to get sound.

Well, the Brickwall effect has negligible latency, per the web site latency chart (that was so nice of them to have one of those).
 
And, I didn't find any info regarding Valhalla Room, on it potentially causing latency issues.
 
So, I don't know, at the moment what's going on.
 
How many tracks do you have present?  How many synths are loaded?
 
Bob Bone
 

Take some time to verify your routings, even disabling FX "feeding" your master buss. From a cursory run on the last several post it seems you may have an effect with a bad output assigned (check effect chains too).

mleghorn
Bob,
 
When I bypass all effects I get sound when I play.  When I hit 'E' again to enable effects, I get no sound. I can toggle back and forth and I always get the same results. Maybe we're getting somewhere? 
 
 
 
Thanks,
Mike

I had this same issue so I disabled plug ins one at the time and would hit play to see if it would go until I found the plug in that caused the problem, not just buses but tracks too. Turned out to be one of the vx 64 plugins. Reinstalled the plug in that was at odds and have not had the problem since.