Help with thud thud (or whop whop) from the front end

I drive a 01 325 ci with 215k miles on it but it runs good. I recently noticed a thud thud sound (or whop whop sound) coming from the front end. It is more distinct and prominent at lower speed (20-45 mph). I replaced the control arm bushing but the noise remains. The DIY dude who helped me replace the CAB suggested that it might be a bad wheel bearing. Any suggestions before I take it to the dealer and have the bmw mechanic pinpoint the cause of the noise?



Additionally, I began to notice the noise after I replaced all four tires. Haven't hit any potholes since that time. I rotated the wheels but the noise remains. Again, any suggestions will be looked into (and please give me pointers on how to check the suggestions). I appreciate all the helpful tips.