1999 360 strange clicking sound

my 360 has a click clic click sound that varys with the speed of the car.it is noticable from3 to about 25 mph,after that there is too much regular engine noise to see if it is still there at higher speeds.i do not see any stones in the tire treads,just had brakes done recently,and cant seem to be able to find the source of the sound.imput from any one who has any ideas would be appreciated.