sounds to me like the howl i get after 4,000 or 5,000 miles on the rear tire (bridgestone).

as the tire wears the rubber on the leading edge of the tread grooves presses into the groove as opposed to wearing off.
it creates little "points" that protrude.

so when ever i lean over into curves i can hear a "humming".

listen closer maybe the "howl" is from the rear