Specifications JBL ES150B Specifications:Frequency response: 27Hz – 150Hz Amplifier RMS power: 300W Amplifier peak dynamic power**: 500W Crossover frequency: 50Hz – 150Hz; 24dB/octave, continuously variable Driver: 250mm (10") PolyPlas Dimensions with grille (H x W x D): 457mm x 337mm x 387mm (18" x 13-1/4" x 15-1/4") Weight per speaker: 17.7kg (39 lb) ** The Peak Dynamic Power is measured by recording the highest center-to-peak voltage measured across the output of a resistive load equal to minimum impedance of the transducer, using a 50Hz sine wave burst, 3 cycles on, 17 cycles off. Measurements:
Frequency response, outdoors, at 6 inches.
Frequency response, outdoors, at 1 m, tip of mic against the ground.
Distortion, outdoors. At 100 dB SPL @ at 1 m, tip of mic against the ground, distortion stayed well under 2 % through the usable range up to 200 Hz. At 105 dB SPL @ 1 m, shown below, distortion stayed well under 3 % through the usable range up to 200 Hz. At 110 dB SPL @ 1 m, distortion was just under 10 % at 44 Hz, stayed well under 7 % above that to 100 Hz, and well under 4 % above that to 200 Hz. Remember that distortion is far less noticeable at these frequencies than in the mid- and high-frequency ranges.
Room modes ganged up to almost eliminate the octave between 100 and 200 Hz. It was possible to vary crossover parameters and phase shift to almost eliminate their effects, as the overlaid plots show, but SS&I suffered greatly, as found in listening tests.
A set of crossover vales was arrived at by trial and error that greatly improved the response through that frequency range while improving SS&I rather than degrading them. Note that in-room response was strong clear down to 25 Hz. These curves were taken before the final tuning was done. I am still investigating ways to improve the frequency response between 100 Hz and 200 Hz.
Measurement Methods Asus G74SX Laptop, Intel I7-2670QM @ 2.2 GHz, 16 GB DDR3 Memory, Windows 7 64-bit, Room EQ Wizard, foobar2000, Reaper DAW Digital Audio Workstation, Phenom II x6 1100t @ 3.5 GHz, 16 GB DDR2 Memory, AMD Radeon HD 6670 Graphics & HDMI Media by Sapphire, Windows 7 64-bit, Room EQ Wizard, foobar2000, Reaper DAW Digital Media Server, Phenom II x6 1055t @ 2.8 GHz, 8 GB DDR2 Memory, AMD Radeon HD 6450 Graphics & HDMI Media by Asus, Windows 7 64-bit, Room EQ Wizard, foobar2000, Reaper DAW Roland Quad-Capture Audio Interface M-Audio Fast Track C600 Audio Interface M-Audio Firewire 410 Audio Interface Beyerdynamic MM1 Measurement Microphone American Recorder SPL-8810 Sound Level Meter Axiom ADA-1250 4-Channel Power Amplifier, Courtesy Axiom Audio Onkyo TX-SR705 Receiver Bosch DLR130 Laser Distance Measurer Fluke 77 Multimeter P3 P4400 Kill-A-Watt Electricity Usage Monitor CyberPower PP1100SW Sinewave UPS
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