If the sound is prior to braking I would say that it is something caught between the dust shield and the rotor on one of the front wheels. You said that you went to a car wash and flushed stuff out, but did you just do the rear? I had a rock get wedged in between the dust shild and the rotor in my passenger front tire and it made an awful noise. To get the rock out we had to remove the wheel, loosen the dust shield and finally pry the rock (actually a pebble) out; it was wedged in there that good.
I say "we" above, because the rock removal was a group effort at The Portal, in the dark, a couple of years ago in Moab.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless