[Update 2]
I believe I tracked it down to VoiceMeeter and Sonar interfering with one another's access to the audio engine. I started VoiceMeeter and then Sonar. Sonar was taking almost 100% CPU. I restarted the audio engine in Sonar, but as soon as it restarted, the CPU climbed back up. Then I restarted it in VoiceMeeter and that did it. No noise and a happy CPU.
 
Other than this little glitch, VoiceMeeter is a nice piece of software.

Cactus Music
USB mikes are a huge waste of money... they rarely work with a DAW and they can't be used with any proper audio equipment.

I mostly agree, but there's no inherent reason USB mics have to be bad. USB mics were designed originally to hit a price point for VOIP, Skype, dictation, etc. As a result they had no need for audiophile specs. Ultimately, what determines the performance of a USB mic is the preamp and converters. Although you're not going to get $500 converters in a $200 mic, the converters in affordable 24-channel digital mixers aren't $500 converter either, nor are the ones in most multichannel audio interfaces.
 
I've used USB mics while traveling and some of them are quite good. Some are execrable  All of them are good for getting into spiriting conversations with TSA agents.
 
Although USB mics are generally not designed for studio work (e.g., form factor), I've evaluated some USB mics recently that were surprisingly good...but they also weren't cheap. I would not hesitate to use them if pressed, or I'd run out of conventional mics.
 
The really one nice thing about XLR connectors is they're not dependent on Microsoft and Apple deciding what's the port du jour. Good thing I don't have any SCSI mics sitting around...

Craig - Now I have a new word to use in a sentence this week - execrable!