i have this too... i had my brakes changed at DR SHOCKS, also lowered my car 2", brakes required new disks and pads as the disks were heat scored. ever since i have had the brakes changed i have found that when you come to a slow pace to stop it sounds like *duddududududududududud*
I had much the same problem with my car. Took it to my mechanic and he found that whoever had the car before me had really cheap pads installed. He changed them for good Bendix pads and haven't had a problem since!
I swapped my discs on the front for some DBA slotted and some bendix ultimate pads....no noises at all, even with the stock discs and bendix pads i had no dramas, but i think your problem could stem from the brand of pad youre using as previously mentioned
