My Cell phone , a motorola Iden 1000 on Nextel Service causes magnetic interference with most speakers including magnetically shielded computer speakers, a clicking or crackling when the phone is close enough to them. I have seen various other cell phones do this too. AT&T's digital Startac does it as well to speakers form my experience with it.
As for the battery terminal, I'm not sure if a nut that wont fully tighten is the issue, have you used any anti corrosion gel, spray or pads?
Also if the corrosion was not completely removed when the new battery was installed, I believe it can spread quicker.
I usually use a wire brush to rid my terminals and cables of the corrosion, then I use some anti corrosion stuff to prevent corrosion.
Hope that helps..
Metallic Black (Blue Flaked) on Parchment
Black Grille Insert
17" AMG Monoblocks or EVO II's
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