I believe that would be via the ASIO Panel in Sonar.
I know you could get to the M-Audio2496 that way, and my EMU-0404 and the Akai work the same way.
The EMU had Patchmix to control routing, which was separate, but latency was controlled from within Sonar.
Here's what I see with the Akai:

I haven't pushed the 64 sample setting yet, because 128 is actually pretty comfortable, and feels a lot tighter than the numbers seem to indicate. I might check it out this weekend, because this newer machine is considerably more capable than anything I have had previously.

Thank you Robert for posting that screen shot.
 
It tells me what I am hoping to learn.
 
For example; on my old Win XP machine my old MOTU firewire Traveler mk1 does approximately 3.5ms (measured by me using a loop back) round trip at 64 sample buffers.
 
With SONAR, the way my MOTU drivers work seems similar to your AKAI works. If you open the Audio Console from within SONAR you actually open the same hardware's driver dialogs you can open from Windows.
 
What I was reading about the new M-Audio M-Track Quad is that there is no way to open the drivers using just Windows... which even the M-Audio reps seem to think seems unusual. :-) The M-Audio rep couldn't speculate if there would ever be an update that allowed for that most basic option. 

I can get about 15ms round trip at 128K with the UR44 without audio glitches or dropouts. 
Doesn't the speed of our PC's effect this round trip results?  I don't have the fastest PC that's for sure.
 

Hi Jimmy,
 The speed of the PC's CPU definitely factors into how small a buffer you can run before you experience glitches or drop outs, but the overall round trip speed or latency that you experience, at any given choice of sample buffer size, is determined by the hardware and its specific driver. In this day and age, a lot of the gear uses relatively generic hardware components so often times it is the software, or driver that is unique and separates the good from the very good choices.
 
 Thanks for letting me know about the UR44's round trip at the 128 sample buffer. That is very helpful info for our shopping adventure.

The 44VSL @ 44.1 supports 64 sample buffer, X3 reports 4.9ms RTL
                        

Thank you Scook.

The Presonus AudioBox VSL units are exactly what you're looking for, Mike.

• 4.9ms round-trip latency at a 64-sample ASIO buffer size/44.1k
• Solid drivers
• Pretty good sound
• Affordable

Thanks very much Jim.

Well Mike, don't recommend the Tascam UH-7000.  I have an 8 core computer (with a lot of dongles and such, although I haven't usb tuned it) and I get 10 ms roundtrip.  Superior sound but a tad expensive, so that knocks it out too.  But it is a great bit of kit.
 
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