这是加拿大的测评:
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Equipment Measurements
June 2006
JBL L890 Loudspeakers: Measurements
PLEASE NOTE: Our standard is to provide the THD+N measurement at 90dB with a measuring distance of 2 meters (within the anechoic chamber). Since this speaker produced low distortion levels under those conditions, we have added a second measurement performed at 95dB to give an indication of performance under higher-output conditions.
All loudspeaker measurements are performed independently at the National Research Council of Canada. Please click to learn more about how we test loudspeakers there. All measurement data and graphical information displayed below are the property of SoundStage! and Schneider Publishing Inc. Reproduction in any format is not permitted.
Chart 1 - Frequency Response and Sensitivity
Microphone measuring position: between tweeter and midrange
Grille: off
Sensitivity: 87.5dB (averaged 300Hz-3kHz, 2.83V/1m)
Frequency response, 20Hz - 20kHz (measured @ 2m, plotted @ 1m)

Top curve: on-axis response
Middle curve: 15 degrees off-axis response
Bottom curve: 30 degrees off-axis response
Frequency response, 20Hz - 20kHz (measured @ 2m, plotted @ 1m)

Chart 2 - Listening Window
Listening Window, 20Hz - 20kHz (measured @ 2m, plotted @ 1m)

Response curve is an average of five measurements:
on-axis, 15 degrees left and right off-axis,
15 degrees up and down off-axis