Howling sound - what is it

[mr_z4mc_oz]

I was driving my z4mc ('07 with 47,000kms) last night and noticed a faint howling sound when the car was moving only. It stopped when I was stationary.

Its very hard to pinpoint where its coming from over the engine sound and s-sprint exhaust.

Any ideas what I should look out for would be greatly appreciated.

Thanks

 

[Bad_Pritt]

if it's a noise from winds, Iwould check the front of the , see if everything is still well attached. That's what I did and noted that the undertray behind the bumper had come loose

 

[srhutch]

Stone between disc and pads?