Hey Zippy
Last summer I put on a set of Elite 4's. They ride real nice but occasionally made a lot of noise. It almost seems like if the temperature and texture of the pavement are just right those tires really sing.
At first I thought it might be a front wheel bearing but there was no grinding feel and the wheel was tight when I pulled over. It didn't happen all the time and I still haven't pinned it down to what pavement conditions do it.
When I get back on the road this year I'll pay more attention to the conditions but I'm sure my noise is the tires. I wouldn't rule that out on yours.
But, the next time you get that noise, if you think of it, pull in the clutch and report back. It will surely make someone feel better.