Instead of having the looped region repeat incessantly, I want to control starting the replay of the looped region.
In other words, "Play loop region once and stop"
 
(I my be misremembering, but I recall older versions of Sonar had "Play loop region once and stop" option.)
 
Can I do that in Sonar Platinum?

I don't think it's possible. Although you can shift+spacebar to audition a selection, it automatically creates a loop around the selection - I think the assumption is if you want to audition just that part you might want to hear it repeatedly, and if not, you'll just hit stop when you've heard enough.
 
However, one useful aspect is if the Now time isn't at the start of the selection, shift+spacebar will start playback at the beginning of the selection anyway.
 
You might want to propose a feature request that shift+alt+spacebar plays the selection but doesn't enable a loop.
 
What I'd really like is the option to have playback skip over a selection, like Sound Forge can do. Hmmm...maybe a feature request for that is in order. 
 
 

I am shocked.
Imagine overdubbing a tricky section needing multiple attempts and a moment for preparation between takes (and you want it to start and at exactly the same points each attempt). Right now there is no way to make sure the target section stops and starts at exactly the same points.
 
I am almost sure I used a "loop once and stop" option many years ago in Sonar.
 
So yes...Guess a feature request is best suggestion at this point.

Punch recording?

That does exist.

You can also just expand the region and loop, that's my favorite.

dougalex
I am shocked.
Imagine overdubbing a tricky section needing multiple attempts and a moment for preparation between takes (and you want it to start and at exactly the same points each attempt). Right now there is no way to make sure the target section stops and starts at exactly the same points.

I'm glad you defined the task you wanted to do rather than what you think you need to do to accomplish that task, because unless I'm totally misunderstanding what you want, punch recording should take care of you. Define the region you want to punch. Create a loop longer than the region to be punched, with as much pre-roll and post-roll time as you want compared to the punch region. Set the Now time before the section you want to punch, probably at the beginning of the loop but you don't have to. You can also set an option to return to the Now time after you hit stop, or not.
 
You can also forego looping entirely and just go through punch once. You'll have as much time as you want to prepare between takes, SONAR will start at exactly the same point on each attempt, and if you set the loop point past the punch you can either let it start over if you want to re-punch, or stop before it hits the end of the loop.
 
There's also comping, which if you do the "speed comping" can be wicked fast.
 
The only drawback to punching is if you leave punch enabled and want to record somewhere outside of the region you defined for punching. This is what accounts for 99.9% the "SONAR doesn't record any more" threads.

Anderton,
 
I don't think you understand the true convenience of what I am actually suggesting.
 
If I have option "play loop once and stop"...THAT MEANS
1] The start and stop is always the exactly same
2] There is never a unnerving accidental restart of the loop (playback always just stops where you expect)
3] (This is the big one) I literally have "one single key press" for every take. 
 
Your method cannot guarantee that the loop does not jump back and start playing before you "catch it". Or if not using loop region, you still have to intervene to "stop" playback (while you might want to be thinking about the performance of the take you just heard).
My method is like having a computer that knows exactly where I want to stop. (What a concept!)

I typically do a 2-bar pre/post roll and simply loop record in comp mode (no punch used). I discovered recently you can delete garbage takes afterwards with the transport running - let it loop/play while promoting with the comp tool, and can simply hit delete. This works on full takes (prior to splitting) and sections post splitting. For what I was doing, I was unable to start/stop the transport, so simply recorded and deleted the garbage takes/phrases when comping.
 
Edit: For the purpose of the OP, Punch Recording seems the most useful. If not set as a loop, I believe it makes only a single pass and records only the defined punch section (I honestly have never used this feature).

dougalex
I don't think you understand the true convenience of what I am actually suggesting.
 
If I have option "play loop once and stop"...THAT MEANS
1] The start and stop is always the exactly same
2] There is never a unnerving accidental restart of the loop (playback always just stops where you expect)
3] (This is the big one) I literally have "one single key press" for every take. 
 

I guess what's confusing to me is you're using the word "loop" to represent a region that you actually don't want to have loop. If you use punch recording and don't create a loop...
 
1] Where you start the transport, and where recording starts (which doesn't have to be where the transport starts) and stops, is always exactly the same.
2] There is never a unnerving accidental restart of the loop because there is no loop.
3] Press "R" and you have "one single key press" for every take. 
 
The only difference is that the transport doesn't stop playback automatically after recording, but so what? It's the region that gets recorded that matters. And when you stop playback, you can have the Now time scoot automatically to your start point, hit "R", and do another punch recording. I just don't see how that's an onerous workflow. I guess I just don't consider it a big deal to stop the transport manually after the punch has happened, especially given that one "R" keypress later, I'm back to recording.

Markers are also your best friend in this situation, with keyboard shortcuts to jump to previous/next markers. Then even if you stop late, is easy to hop back to the take start.

Anderton
...punch recording should take care of you. Define the region you want to punch. Create a loop longer than the region to be punched, with as much pre-roll and post-roll time as you want compared to the punch region. Set the Now time before the section you want to punch, probably at the beginning of the loop but you don't have to. You can also set an option to return to the Now time after you hit stop, or not.
 
You can also forego looping entirely and just go through punch once. You'll have as much time as you want to prepare between takes, SONAR will start at exactly the same point on each attempt, and if you set the loop point past the punch you can either let it start over if you want to re-punch, or stop before it hits the end of the loop.

This is exactly a part of my regular workflow. Make sure that you have the right box checked to go back to the Now time after you hit stop. I rarely loop record...typically only when I'm experimenting with a melody in composition...but will often use Ableton Live for this. Loop record (particularly with MIDI instruments) generates lots of funny clips and overlaps from notes that are close to boundaries (but on the 'wrong' side!!)