Manufacturer: USA, 1978
Specifications JBL L-300:
3-way speaker with phase-inverter
Sensitivity: 93dB (1W/m)
Power rating: 150 W
Nominal impedance: 8 Ohm
Frequency of the filter section: 800 Hz and 8500 Hz
Speakers used:
LF: 380 mm, model 136H (paper not foam)
MF: 44 mm, model LE85 (aluminium)
Tweeter: 25 mm, model 077 (aluminium)
Finishing: walnut veneer
Dimensions (HxWxD): 803x584x572 mm
Weight of one speaker: 66 kg
Description JBL L-300:
The cabinet is in the form of a rectangular, non-disassembled chipboard drawer. The front panel is sloped. The inside of the case has spacers and stiffeners. The exterior finish is made of natural veneer. Everything is fastened with screws. The interior padding absorbs stray reflections and standing waves. The grill is attached to an inset covering the entire face. It is a solid wood frame covered with acoustically transparent fabric. The difference from the JBL L300 model is the use of a different woofer.
The tweeter and midrange drivers are arranged in a horizontal axis over the woofer. The tweeter and midrange are mounted on the inside of the speaker and the woofer on the outside. To the right of the midrange and tweeters is a nameplate with the model name and the company logo, as well as midrange and treble controls. Just below, between the mids and tweeters, is the reflex port. Everything is fixed with screws. The internal padding absorbs stray reflections and standing waves. The grill is attached to the inserts, covering the entire face. It is a solid wood frame covered with acoustically transparent fabric.
The woofer has a voice coil with a diameter of 102 mm. It is wound with copper wire. The magnet is ferrite. Diffuser with the cap is made of paper, suspension – foam. Center washer is made of cloth. The frame of the speaker is aluminum.
The LE85 model compression driver serves as the midrange driver. It has an aluminum dome driver. The voice coil has a diameter of 44 mm. The magnet is alnico (19000 Gauss) weighing 4,5 kg. Used with a horn and sound diffuser JBL HL92.
The 077 tweeter is a ring radiator made of aluminum. The voice coil is 44 mm in diameter. The magnet is alnico (16500 Gauss). The 077’s dispersion is 130° at 15,000 Hz, wider than any other existing unidirectional tweeter. Even at frequencies as high as 20,000 Hz, the dispersion is 110°. But a parameter as important as dispersion is only the first part of the success. As a horn-loaded, circular radiator, the 077 is extremely effective. It has so much extra acoustic power that no power amplifier designed for home listening would be able to overwhelm it. The 077’s bandwidth in the L300 begins at 8500Hz and extends smoothly beyond the range of the human ear. With this high efficiency and extended frequency range, the 077 reproduces instant bursts of sonic power with outstanding accuracy and clarity. On the bottom of the loudspeaker there are the electrical filters, which are covered by a metal cover. On the back wall are the output terminals.
