Can you try hooking it up on the bench without the car to see if you hear the same sound? You don't hear the static sound on the radio at all? I haven't had a problem yet with that alpine unit but it sounds like a problem with the radio. If you don't get an answer ther try calling alpine tech support @ 800 tech 101 if you dont have any luck give us a call @ 8004676545.

Scott

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The Mercedes Specialists Since 1986