I acquired a pair of used KG2s, one of which has a black midrange K-9-K, and the other a white plastic one that the previous owner indicated was replaced by Klipsch under warranty. Were there iterations of the K-9-K driver, and did they have slightly different properties? I've noticed that the original, black K-9-K doesn't sound right when I run a 30 Hz test frequency-- it vibrates much more strongly than the other and practically buzzes. Above this frequency (around 50 Hz), they're more or less comparable to my ears.
