Ugh- I'm sad. I thought all was going well with my BT 7.1 Titans and my RF 300x2 amp. No noise when engine is off. Happens in all modes FM, AUX, etc, and when my XM module is unplugged from the HK HU. Its not RFI induced as it does not vary frequency when the engine RPMs go up. The cracking happens at the same level independent of the volume control. Bad left channel output in the amp? Need to take the outer fairing off and check that all of the connections are solid. Wondering if it is a bad voice coil in the speaker that rubs when the bike running and is vibrating? Amp is mounted on an EZELL bracket so wondering if its heat induced? Guess I will need to switch LR speaker outputs, reinstall the fairing and go for a ride to hear if it moved. PITA.

 

swap your speakers around and see if the problem moves to the other side. If it does, it's a speaker. If it doesn't then swap inputs to the amp around and if it changes to the other side, then it's the radio. If neither of those work, then it's the amp.