Originally Posted by sunpole
Vocal sounds fine, do you suspect the tweeters are defective?
I already cut the original connector off for both front speakers and tweeters and I was hoping I'd never have to take those doors apart again, arg!
It could be possible one crossover is defective, less probably both.
I was looking to remove the front speakers variable and concentrate in the possibility of the RCA signal as the source of the problem. In other words, if the noise was still there with the OEM speakers then there must be something wrong in the harness RCA contacts -assuming the same problem with two different amps and two different RCA extension cables.
If the noise goes away with the OEM speakers then the problem must be the crossover circuit.
Unplug the tweeters at least and see how this affects the noise.
-2015 F30 320i, Imperial/Oyster, 8AT, ED
-2012 E92 M3 Jerez Black/Rust Brown, M-DCT, ED: Gone
-2008 E90 M3 Melbourne Red/Bamboo, 6MT: Gone
-2007 MK5 GTI United Grey/Grey, DSG: Gone
-2004 E46 M3 Carbon Black/Cinnamon, 6MT: Gone