Thanks for responding dboucher.
Solution, I think?
Presonus / Configure Audio Device / Audio Setup / Audio Device - select Focusrite, Device Block Size 512
Control Panel / Sound / Playback tab /
- Set As Default
- right-click Focusrite USB / Properties / Advanced tab / Exclusive Mode, uncheck Allow applications to take exclusive control of this device
Control Panel / Sound / Recording tab /
- Set As Default
- right-click Focusrite USB / Properties / Advanced tab / Exclusive Mode, uncheck Allow applications to take exclusive control of this device
Here's what I think cleared things up - Start / ASIO Control Panel / set samples to 512, not 8 ?!? (I kept seeing ASIO bubble in the task bar when I loaded up Studio One, and I finally clued in that ASIO was my motherboard's sound, not the Focusrite, I think).
I followed the Sweetwater advice on optimizing the PC for audio with Win7, including "#7. Disable USB Selective Suspend (for USB interfaces). This prevents your hub driver from suspending an individual USB port. To do this: Start - Hardware and Sound - Power Options - Change advanced power settings - USB Selective Suspend and select 'Disabled'"
So far so good. Loads up fine no matter what other audio software I'm playing.