Sounds like a lose connection or BAD tweeter not one breaking in. Does it make the noise regardless of if vehicle is in motion or running or just on accessory? One way to tell off loose connection if the vibration of running engine or movement makes it worse.
But since others are noticing it may be poorly shielded cables to or from amp which may be picking up interference from veh alternator or other source in the electrical system. Sometime PIA to diagnose these because it can be as simple as a speaker wire running too close to another wire carrying power somewhere on the vehicle.
2011 WK2: Limited, 4x4, Hemi, 730n, Class IV Tow, Brilliant Black. 30% Ceramic Tint, Lockpick, LED DRL, LED License Plate, LED Backup, LED Liftgate (all), Axle/Transfer Case OEM add-on skid plates, Sharkfin Antenna.:thumbsup: