I agree it is more of a harmonic vibration. For me it generally occurs between 30 and 50 mph, with slight pressure on accelerator, in V4 mode. We never feel (hear) it at highway speeds, >50 mph, even in V4 mode.
Fortunately the truck doesn't appear to have any of the other issues mentioned...booming, buffeting, ear pressure, even after 23k miles. Maybe it's because it has 18" wheels? I could be I just don't notice it, but I'm pretty sensitive to noise. Ask my kids