Okay, I think I'm figuring this out.
SooperLooperAU seems to default to only 1 loop on first use. "select_next_loop", etc, doesn't do anything because there are no other loops available.

- Default SooperLooperAU with only 1 loop
- SL default 1 loop.png (66.91 KiB) Viewed 3558 times
To fix this I clicked on the SL GUI. This brings up the SooperLooper menu bar in OS X. From there, I added 3 more loop channels (command 2).

- add more loops menu command
- SL-addLoop.png (54.92 KiB) Viewed 3559 times
Now, the AU GUI shows 4 total sets of SooperLoopers.

- SooperLooperAU now has 4 loops!!
More can be added
- SL with 4 loops.png (161.09 KiB) Viewed 3559 times
The reason I didn't know SooperLooper worked this way is because I never launched it as a standalone to check out how it works. As a standalone, I discovered that I could drag the window to reveal more loops. Then using the key bindings 1,2,3, I could select the different loops. (That never happened in the AU). I recommend to anyone having trouble with the AU to launch the standalone App first in order to grasp how it is designed to work before diving into AU land.
Now that the AU instance has 4 loops, when I trigger "select_next_loop" I see "selected_loop_num" changes to reflect the current loop selected. I haven't tried recording or routing audio yet but I'm sure it will work now.
This blows my mind. This means I can overdub a bunch of loops into loop 1 of SooperLooper, then select the next loop and add a bunch more to that one. And then I can control those 2 loop individually. Amazing.
my worthless 2 cents: I find the naming conventions to be a little bit confusing. What is a "loop"?
In the SooperLooper menu it says add loop. To me I thought that's what I was doing every time I hit overdub, or added a new layer of sound. I personally consider an SL loop more of a "loop group", "loop track" or "channel" or something like that.
I consider all of the overdubs recorded onto a single SL Loop as individual loops because they are not destructively rendered as 1 pattern, it is still possible to play with them using "undo" + "redo".
Or maybe I could call what I record to be a "cycle" instead of a loop. And that each SL Loop can contain many layers of "cycles".
Regardless of naming conventions, this latest discovery of having multiple loops, each with the possibility of being very sonically dense thanks to overdubbing, really blows my mind. What a versatile piece of software!!
Thanks,
Zef