Cell phones will interfere with most car electronics. Don't put your cell phone near your head unit. It will make noise if you have it near your amps too, but i don't usually have the cell in the trunk.

At home, i keep my cell near my sub so it warns me before it rings.

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Alpine CDA-9887, TUA-T500HD, CHA-S634, CHA-1204 & KCA-410C
Pioneer TS-A6981, 6 x GM-5100T
Kicker 2 x CVR15,
MBQ RCE-216
PG MX2
Soundgate LanStar1
PAC SWI-ALP