Fluttering Sound-Front End Right-97 Nissan Sentra

Could anyone please tell me the most likely causes of a definite fluttering sound which seems to be coming from the passenger side, front end of my car (probably the wheel but not sure). The car is a 1997 Nissan Sentra with 152,000 miles. I replaced the right front axel about 5 months ago.



I thought immediately of a wheel bearing, but I never associated a bad wheel bearing with this kind of a distinct flutter. It starts around 30mph and gets worse at around 40mph. It doesn’t seem to make any difference whether I am turning either direction or going straight. (Sounds almost like the sound we produced as kids when we put playing cards on the spokes of our bicycle wheels).



Thanks

by worse, do you mean louder? faster? both?

Definitely louder.

(I haven’t noticed it to be any faster, but would appreciate any thoughts you had on all reasonable possibilities).

Thanks