Again, the closest thing I have to "Configuration -> Sound cards -> ... " is Configuration -> FM sound card. I do not see any means there for changing the sample rate. If there is supposed to be another (separate) sound cards area, I'm not seeing it on my end.
It's probably moot now though, I wound up just getting rid of that Xonar U5 card.
I've put in it's place a Behringer UMC202HD. I simply installed it's driver, plugged it in, launched ST, set the device setting to WASAPI, clicked to play a file... Wala! we have full stereo sound! (so FYI, the WASAPI mode does appear to be working
It still sends at 176.4kHz, but with the Behringer it seems everything is working that I can tell.
I tried the regular MME setting and the stereo separation went away entirely, so WASAPI is apparently a necessity with the Behringer (I don't know if this is a new feature you added because of seeing my dilemma here, but if so, I appreciate it very much Hans. Thank you).
Sure enough, it also outputs a decent square wave using 102,099µs of tilt correction:
Incidentally the UMC202HD was also about $10 cheaper than the Xonar U5, so that was just a bit of icing on the cake.
So I guess this thread has now run it's course.
Again, I appreciate your help.
If I notice any bugs or other issues in your beta, I'll be sure to let you know.
(a minor one is several of the tool tip windows come up blank or are absent entirely, perhaps you're still in the process of composing them)
P.S., I found the spectral hole filter.. That was the issue, I guess it must've been enabled by default.