Well here is on example: Total Harmonic Distortion (THD), 2500 ohms load
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''COL. KLIPSCH: It is a matter of fact, not opinion, that a single direct radiator of small size will give a more nearly flat
response over a wider range than some larger and more complicated systems. But likewise it is a fact that a small direct - radiator speaker, say six inches in diameter, would have to perform an excursion of several inches to produce a barely audible fundamental output at a few feet distance at some low frequency like 60 cycles, which, even if possible, would result in distortion many times the fundamental output. It is also a fact that when two or more frequencies are mixed in a single piston radiator, the lower frequency amplitude will modulate the upper one, which causes the oft -referred -to inter - modulation distortion. The result of recognition of these facts is that the best loudspeaker systems now employ at least
two loudspeaker elements. The design problems entail minimizing the frequency anomolies and interferences between a pair of speakers radiating the same frequency
near a crossover point. At present, only multiple speakers have been capable of duplicating the sound to a high degree of accuracy.''