Sounds like the shims on the carrier are missing or loose. What pads did you use?
The hissing/rubbing sound is probably from the thickness of the pads. The pads are always touching the rotor, it's called drag. Usually when the pad mates with the rotor this noise gets less pronounced.

Perhaps, as an after thought, your front end (ball joints, tie rods and associated bushings) may be worn or wearing.