Front end noise, not hub?
 

Hearing a buzzing noise from the front of the car. Begins at about 25mph. Follows vehicle speed (changes pitch), not engine speed. Doesn't sound or feel like a wheel bearing. Rides fine at city and highway speeds. Both my front hub assemblies were replaced within the last 20,000 miles. Is there anything in the hub other than the bearing that could make noise? Any other things to look for?
Thanks,
John

Easiest thing to check is to rotate the tires and see if the sound follows or stays in the same place...

A "Buzzing" that follows road speed could be anything, really... even a loose body panel could do that. (Or the center cap on a wheel... thus, the rotate the tires deal)

I'd still be looking at a hub although that seems odd if you just replaced them. In the summer of 2018 mine made a sound like a playing card makes against spokes when clipped to a bicycle wheel. I've never heard a bearing make that kind of noise before but that's what it was.

Other things are as Greybeard suggested.

Yeah, my first thought was a loose splash guard or something hitting a tire. Can't see anything like that at first glance. Plan to rotate tires next. Just trying to think of things to look for.

I've heard that description for flex pipe.