I have an aftermarket head unit and speakers.
When I first got this head unit it would make a similar noise. The previous one did not.
Added an aftermarket amp, this is when the noise started happening.

It only happens in my left rear door speaker. Sounds like a space ship.
Static, high pitch frequencies, static burps etc. Only lasts a few seconds.
Rarely occurs

Happens at 0 volume, happens at max volume but the sound is not amplified.

What could be causing this?
Bad ground? (o awg ground)
Bad Wiring?

Not my patch chords - Monsters (I have tried 3 different sets)
Big 3 upgrades'
Ground is good, on amp and head unit.
Amp is not touching vehicle chassis.
Power is on one side of the vehicle, RCAs are on the other.

Not sure if head unit or amplifier

Help me out guys! Thank

Similar to this. : http://community.crutchfield.com/car_audio_and_video/f/26/speakers/t/25273/speaker-buzz-that-is-temporarily-fixed-by-rolling-one-window-down-and-up-any-ideas
It's a kenwood bluetooth deck.