strange noise driving me crazy help!

[Dashvortex]

ive got a weird noise with my recently purchased 04 civic ex coupe. its like a low tone, muffled du-uh-dut sound is the best i can describe it. kind of similar to the dut-uht sound of driving over the expansion cracks on a concrete road but lower tone and a bit quieter. it sounds as if it occurs with every rotation of the wheels and has a slight pause (half a second or less) between reoccuring. it speeds up and slows down with the cars speed but only is noticeable between 45-65 mph and is loudest at 55. it does it in neutral and in gear and brakeing dosnt seem to change it any. the only thing that changes it any it taking a slightly hard right corner at about 55 then it makes the same sound twice then has a shorter pause more like a du-uh-dut-du-uh-dut if that makes any sense. it definitely sounds like its coming from the drivers side rear wheel area so i rotated the tires/wheels around in all different combinations and it didnt change anything about the sound. so i figured it must be a rough bearing or brakes so i swaped out the whole spindle, hub and bearing on that corner of the car, changed the rear brake shoes and hardware and resurfaced the drums and rotors and still have the exact same noise. the car does need an alignment but it doesnt show any irregular tire wear im starting to think it may be a suspension component though i cant find and play in anything and it sounds like a spinning type noise for sure.

any help is greatly appreciated, this sounds driving me nuts!

[somick]

It might be a muffler or a heat shield.

Sam

[Dashvortex]

thanks for the suggestion. ive checked all the exhaust mounts and shields and they all seem good and solid with no contact anywhere. also laid under the car while running and theres no noticeable exhaust leaks at idle. im almost sure the noise is something spinning though as its very consistant and occurs regardless of rpm but only between 45-65 mph