DETUNED

To intentionally lower or raise the pitch produced by a musical instrument. Often done to produce sounds not normally possible, or in the case of stringed instruments to reduce tension for the purposes of shipping or maintenance.

"Some avant-garde composers request that performers detune their instruments before playing."

To alter the capacitance of a circuit such that its resonant frequency differs from the incoming frequency.

Having undergone detuning.

"a detuned instrument or device"