I have a resonating sound, but mine starts a little
lower, perhaps from 50mph onwards, getting progressively more frequent the faster you go. Very annoying on motorway miles.
For me, i'm 90% sure it's the wheel bearing. (Tell me if i'm wrong!) I hit a gigantic pot hole a few months ago, which threw the alignment out of whack. I got that fixed that but since then have noticed this annoying resonating sound coming from the same side. ( Near-Side Front ) It's on my to do list.
..I do also have 18inch rims.