JGH summarized the KLH Nine in October 1968 (Vol.2 No.10):
KLH Nine: Low efficiency, highly reactive loading characteristic, and superb transient response make this speaker extremely critical of the driving amplifier and input signal cleanness; drivers well-blended; tweeter highly directional, best heard off-axis; sound very smooth, liquidly transparent, likened to a spotlessly clear window on the sound; "Row-M" perspective places sound rather behind panels; somewhat cold sound; two panels (one complete Nine system) essentially flat to around 40Hz with panels together, gradually rolled-off below 60Hz with panels separated for wider stereo separation; with usable bass to around 32Hz in a large room, plus somewhat warmer sound; imaging with two panels (apart) good but optimum listening area restricted; listening area fairly large with four panels, but imaging only fairly good.
This is probably the most nearly perfect loudspeaker we have tested until this time.—J. Gordon Holt
