This sounds like alternator whine. Do you have the power and ground connected to your battery, or through the accessory power? Make sure the power and ground wires are sufficient size, and connected to your battery, and make sure you have the power wire fused no more than a foot or two from the battery. If it is only on the right channely, maybe this wire is getting feedback from another wire. Seperate the wires if this is the case.

Wires create magnetic fields, and if a speaker wire is next to a power wire or something, you will hear a noise, typically high pitched whining.

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