JBL4311音箱

Smooth, powerful, wide-range response within a compact enclosure. Components: 300 mm (12 in), long excursion, low fre- quency loudspeaker; 130 mm (5 in) midrange loudspeaker; 36 mm (1.4 in) high frequency direct radiator; matched fre- quency dividing network with front panel controls for mid- range and high frequency output. 90” dispersion allows vertical or horizontal placement. A product of JBL’s long experience and intimate involve- ment with the recording industry. the 43llB is a powerful, yet compact monitor loudspeaker system. Its wide-band re- production at loudness levels required in professional work make the 43llB ideally suited for control room installations, small studios, mixdown facilities, broadcast monitors and portable playback systems. Low Frequency Loudspeaker Bass material is reproduced by a powerful, long excursion, 300 mm (1’2 in) loudspeaker having a 75 mm (3 in) diameter edgewound copper ribbon voice coil operating in a mag- netic field of 1.0 T (10,000 gauss). The magnetic assembly weighs 4.7 kg (10% lb); free air resonance is approximately 22 Hz. The surface of the cone is coated with an exclusive damping formulation that provides the precise mass and density necessary to optimize bass performance, prevent spurious resonance and provide smooth performance ex- tending into the midrange region. Midrange ‘Eansducer Transition to the mldrange urut 1s made at a crossover fre- quency of 1.5 kHz. The 130 mm (5 m) transducer provides clarity and freedom from audible dIstortIon, even at the high loudness levels encountered m professional appllcatlons. The transducer IS energized by a magnetic assembly hav- mg a total weight of 0.74 kg (1% lb) and creatmg a magnetic field of 1.35 T (13,500 gauss). The 22 mm (% m) diameter cop- per voice co11 drives a 100 mm (4 in) edge-damped cone that operates as a true piston, provldmg smooth frequency re- sponse and wide dispersion throughout Its operating range. High Frequency Direct Radiator Reproduction above 6 kHz is accomplished by a 36 mm (1.4 in) direct radiator. Its 0.74 kg (1% lb) magnetic assembly ana resonance. Internal padding absorbs spurious reflections and standing waves. All components mount directly to the baffle panel and are removable from the front of the enclosure. A ducted port provides proper acoustical load- ing of the low frequency loudspeaker. 2213H LE252 LE5-10 3112BNetwork notshown LE25-2 Adjustable Response Contour - he frequency dividing network of the 43llB is provided with front panel controls to allow separate regulation of output in the 1.5 kHz to 6 kHz range and the region above 6 kHz. Con- trols are continuously variable from maximum to full off. With suitable settings of the two controls, the frequency re- sponse contour of the 4311B can be altered to compensate for almost any acoustical environment, or to achieve the tonal balance desired. Control scales are clearly marked so that special settings can be logged and easily reset when needed. Performance Characteristics The accompanying graph and specifications were com- piled from measurements made under standard laboratory test conditions. The loudspeaker system was mounted flush in.the.center of a large, flat baffle in an anechoic environ- merit; a calibrated condenser microphone was suspended at a known distance from the sound source, sufficiently far to be safely out of the near field: and all electronic equipment was checked and calibrated before tests were run. The on-axis frequency response of a typical 43 11B does not vary more than 23 dB from 45 Hz to 15 kHz. Due to the wide- angle characteristics of the midrange and high frequency units and their physical orientation, response measured up to 45” off axis, horizontally or vertically, does not deviate more than 6 dB from on-axis response at 2 kHz nor more than 10 dB at 8 kHz. The 43llB’s lack of distortion is equally out- tanding. Distortion is inaudible even at high power levels b&d at very low frequencies, as shown in the photo at right. While specifications indicate that the 43 11B has impress- ive performance characteristics, they cannot convey the full impact of an extended listening evaluation. Clean, crisp, wide-range performance, even at very loud levels, power- ful bass fundamentals without doubling and lifelike voice projection are qualities found in few loudspeaker systems, regardless of size or price. When heard from a monitor oc- cupying less than 71 litres (2.5 ft3), the effect is little less than awesome. Response Frequency resPo”se of the 43llB taken with ‘V-octave band pink Norse. Measured at 1 m with a l-watt (“put 35 Hz Output This unretouched photo shows the acoustic output of the system when dwen by a 50 W Sine wave slgnal at 35 Hr. A laboratory microphone was used to pick up the sound from the 43118 The signal from the microphone was connected directly to a” o~~lll~S~oPe and the trace Photographed. Sustained Performance at this lntenslty would not be encountered during normal “se. A 50 W Sine wave represents a far more dlfflcult job for the loudspeaker than ,ts rated capactty of 75 W program mawal, particularly in the very low frequency range Even so. 11 can be seen that the 43118 produces an almost perfect sine wave. (Note Below 50 Hz, most loudspeaker systems produce substantial dtstortion with an Input of only a few watts ) Specifications JBL continually engages in research related to product improvement. New mate- rials, production methods and design refinements are introduced into existing Power Capacity’ 75 W continuous program products without notice as a routine expression of that philosophy. For this rea- son, any current JBL product may differ in some respect from its published de- Crossover Frequencies 1.5 and 6 kHz scription but will always equal or exceed the original design spectflcations unless Nominal lmpedence 6 R otherwise siated. Hugh Frequency Drspersion Frequency response Sensitrvrty* Drstortron M Power, 95 dB SPU3 m (loft), Single Frequency Finish Grille Dimensions Net Weight Shipping Weight 90” horrzontal and vertrcal 45 Hz - 15 kHz t3 dB 91 dB. 1 W, 1 m (3 3 ft) 42 dB, 1 mW, 30 ft (9 1 m) Less than 1% third harmonrc generation from 100 Hz to 15 kHz Textured arav or oiled walnut Black fabrrc 597 mm x 362 mm x 296 mm deep 23fi in x 14% In x 113/4 in deep 21 kg 45 lb 24 kg 52~lb ‘Continuous program power IS defined as 3 dB greater than continuous sine wave power @MS) It is a conservallve expression of a loudspeaker systems ablllty to handle normal speech and muw program material ZMeasured wth Input swept from 500 Hz lo 2 5 kHz with controls set for flattest re- sponse Unlike many theater type loudspeaker systems that exhlblt sensltlwty peaks I” the mldrange the JBL Control Monitor provides substantially the same sensltlwty through the full range of audible frequencies Measured serwtlwty below 500 Hz or above 2 5 kHz may be corwderably greater than that of other systems with higher sensltlvlty ratings Professional Division James B. Lansing Sound, Inc., 8500 Balboa Boulevard, Northridge, California 91329 U.S.A.