History:
Installed myself new front brakes (StopTech Sport Slotted Rotor, Akebono euro ceramic pads and new sensor). This was back in June.

Last week I went to an open track day. HPDE type of thing. No passing unless signaled, no lap times.

This week we notice when breaking anything beyond light there is a low frequency hum. Not vibrations in the pedal. Pedal might feel a bit lower than normal, but can't be certain. Tires are nearly dead so am installing my winter wheels/tires today.

Here are photos of the brakes w/ the wheels off.

http://imgur.com/a/H7Emu

There is a small barely catches your nail groove on the passenger side from rotor.

 

Have you pulled the pads? Good chance you might've caught a rock in there at some point.

 

thanks, i will go take a look.

 

Good call. I took the front pad off cleaned it with some brake cleaner. Then I wiped the rotor down with a paper tower. Reassembled and the noise is gone. 20+ internet points to you!

Thanks
Will