On The Bench
Benchmark audio tests of the JBL 4367 Studio Monitor Loudspeaker were conducted using a calibrated Earthworks M30 microphone. The source device was a LYNX Two professional PC sound card using test signals created by SpectraPLUS audio measurement software. Measurements for on and off axis frequency response were taken at a distance of 1 meter from the speaker while distortion measurements were taken at 1 foot distance from the appropriate driver.
The JBL 4367’s on-axis frequency response shows essentially textbook good behavior from 500 Hz right up to 20 kHz and certainly a little beyond. Everything below 300 Hz is governed by room modes and is less of a concern at this point with this measurement.
This chart shows the on-axis frequency response directly compared to the 30 degree off-axis measurement. The two plots track each other tightly until we get to about 13 kHz where the treble energy begins to gently roll off.
This graph shows an averaged in room response that was culled from six measurements taken at various points around the main listening area. Unlike the on-axis measurement, this tries to give a better indication of what the speaker’s legitimate response is. There is a very mild upper treble reduction beyond 13 kHz but this is typical for most speakers in room. The entire midrange to lower treble area is exceptionally flat and well behaved. The bass region shows a gentle lift from room gain at 150 Hz down to almost 30 Hz where it begins to gradually roll off.
Distortion measurements for speakers are typically done at a 90 dB reference point but the distortion numbers for the JBL 4367s were low enough that I also measured them at 100 dB to really see what these drivers could do. This is considered loud by any stretch and some lesser drivers would balk at these levels. This particular graph shows a distortion level at 10 kHz of only 0.389017% at 100 db. Essentially inaudible.
At 5 kHz the distortion level at 100 dB is lower still, at 0.364581%. Also, inaudible.
At 1 kHz the distortion level at 100 dB drops even further to 0.096540%!
At 500 Hz the distortion level at 100 dB goes even lower to 0.066376%. That is remarkable and counts towards a squeaky-clean sounding midrange.
At 250 Hz the distortion level at 100 dB begins to rise ever so slightly to 0.080793%.
I seem to have misplaced my 100 dB distortion measurement at 40 Hz but I kept the one I took at 95 dB which shows a distortion level of only 0.127169%. Still inaudible and I guarantee at 100 dB, it was barely any higher than this.
At 32Hz, the distortion level at 100 dB rises gradually to only 0.453090%! Remember that distortion levels in speakers are commonly considered to be audible at levels of 10%.
At 24 Hz the distortion level at 100 dB rises to just below the level of audibility, when measured at the driver, at 9.55191%. This is taxing the driver to beyond the limits of its low-end rating and should be considered an excellent showing at this SPL.
For the sake of comparison when the same 24 Hz measurement is taken at the ports, where most of the sound will be emanating from at this frequency, the distortion level is only 2.639647%!
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