2017 Equinox - harmonic noise in rear at 92 kph

[andyfest]

I bought a brand new 2017 Equinox Premier AWD 2.4L about a month ago and have about 3500 km on it now. I like it a lot so far, having come from a 2011 Buick Regal CXL with the same drivetrain. The only thing that bothers me a bit is a "humming" noise that comes and goes in the rear when I am locked in at 92 kph. If I go below that speed or above it the sound kind of fades away. Anyone else experience this, or have any ideas as to what it could be? I'm thinking that it's some kind of harmonic noise from the tires, but that's just speculation on my part.