The possibility of dynamic intermodulation distortion at the amplifier loudspeaker interface is discussed. This distortion is produced in amplifiers using high values of feedback, and having moderate or high open-loop output impedance in comparison with the loudspeaker impedance. The mechanism is intermodulation between the signal and its delayed versions, generated by the loudspeaker and propagated in the feedback loop. Experimental measurements showing the probability of considerable distortion are described.
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