On some cars a brake caliper that is not sliding correctly will do this...it stays in contact with the rotor and heats the rotor until it warps slightly, then you feel and hear the kickback as it knocks the caliper on each revolution of the wheel. The sound will go away when the brake is applied, but there will be shake in the brake pedal and steering wheel.
If any of that sounds like what you are experiencing, that's where I'd be looking...
Also, rule nothing out...
A lesson I learned in the shop. I once did a complete brake service on a customer's car. Loaded calipers, new rotors, front brake hoses. Two days later she brought it back with a loud thumping in the right front. I went back over my work but found nothing wrong.
Just to be safe, I defected out the caliper and rotor, carefully checked the hub bearing and cv shaft while it was apart, put it back together, and it was exactly the same, noise still there.
It was still on the rack when she came in to get it after getting a ride to the shop from work. Out of habit, I checked the tire pressures after putting the wheels back on. THE RIGHT FRONT TIRE HAD 110 PSI IN IT!!

...the thumping was the bead cords fixing to explode off the rim...
I asked her how it could have happened, because I'd checked the tires the first time it was in the shop. She said "I thought it looked low the next morning, so I put air in it..."
Did you use a gauge?
"No...I just filled it until it looked right..."
So I explained to her how she was lucky to still have hands on her arms after doing that, and how she'd cost me the use of a bay and my time for a whole day...and politely suggested she buy a $2 tire gaugerunaround