What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





JBL L26 Decade

 The L26 was developed through the technology that made JBL the leading manufacturer of loudspeaker system for professional use. It meets the same stringent requirements as JBL studio monitors, providing clear, crisp reproduction, freedom from distortion and lack of coloration - all reasons most major recording groups insist on JBL professional loudspeakers for live performances as well as studio recording.
The L26 achieves the open, effortless performance that is characteristic of JBL loudspeaker systems. It even approaches, within just a few decibels, the thunderous volume levels required of JBL monitors in the recording studio. Each component of the L26 - low frequency loudspeaker, high frequency direct radiator frequency dividing network and enclosure - has been designed to function as part of the complete system, optimizing performance and efficiency without sacrificing definition orthe ability to accurately reproduce the fleeting bursts of sonic energy, known as transients, so essential to realism.
Like all JBL loudspeaker system, the L26 utilizes a ported enclosure to increase efficiency and dynamic range rather than a sealed "acoustic suspension" enclosure which achieves bass response at the expense of efficiency, dynamic range and transient reproduction. Efficiency is important for two reasons; it permits use of a relatively low power, moderately priced amplifier, and it allows the amplifier to operate at a lower power level, providing the reserve necessary to achieve full dynamic range and excellent transient reproduction. Efficiency and outstanding reproduction make the L26 ideal for the music listener wanting to combine superb performance with compact size.

 Technical Information
Each component of every JBL loudspeaker system is designed and produced by JBL personnel to the most rigorous standards in the industry. JBL loudspeaker frames are massive cast structures, produced to exacting tolerances. Magnetic assemblies are precisely manufactured of low-reluctance iron, energized by large, high grade megnets. Voice coils are held to within one turn of design specifications. Stamped frames and mass-produced voice coils would be less expensive; however, the resultant loss of structural integrity, magnetic force and acoustic efficiency would tend to degrade low-distortion performance and transient response - qualities that have become JBL hallmarks.

 The L26 Enclosure
The enclosure, embodyying every concept of fine furniture design and construction that has made JBL leader of the industry, complements the  acoustic characteristics of the loudspeaker system. It utilizes a ducted port extending through the baffle panel to provide the proper resistive load on the loudspeaker cone for improved efficiency and dynamic range. To achieve maximum strength and resistance to vibration, all panels are constructed of 3/4-inch stock, side and back panels are lined with acoustic padding, and all joints are hand-fitted, lock-mitered and wood-welded.
The search for refreshing visual approach to loudspeaker enclosures led JBL to explore the use of new finishes, in this case natural oak. The beauty of its grain structure is brought out by a hand-rubbed oiled finish. The contrast of the contemporary grille and natural finish reflects the most recent decorator trends, permitting use of the L26 as an active design element in the listening room.

 High Frequency -
The 1,4-inch direct radiator contributes to the dramatic  presence of the loudspeaker system and provides accurate reproduction of delicate overtones and harmonicas extending beyond the range of human audibility. Presence creates the feeling that a performance is taking place in front of the enclosure, rather than coming from within it.
As in the low frequency loudspeaker, the high frequency direct radiator combines a large voice coil interacting with a powerful magnetic potential for efficiency and transient reproduction with definition and accuracy. The small diameter of the cone and center dome provides a wide sound distribution pattern, assuring that each listener hears the same tonal balance and blend of direct and reflected sound, regardless of position withhin the listening area.
The entire dynamic assembly is surrounded by a ring of dense foam damping material to absorb unwanted radiation and reflections.

Low Frequency -
Solid, well-defined reproduction is provided by a 10-inch, long excursion loudspeaker. Its massive Alnico Vlow-loss magnetic assembly concentrates all the magnetic energy where it contributes most to loudspeaker performance - the voice coil gap.
A massive die cast aluminum frame maintains the precise alignment of the voice coil within the gap to a tolerance of ane thousandth of an inch. An ordinary stamped frame cannot insure the structural rigidity necessary for long term, low-distortion performance. The copper voice coil, two inches in diameter, drives an integrally stiffened cone. This large coil, interacting with the magnetic force, provides the physical drive necessary for instantaneous transient reproduction; the mass and stifness of the cone have been carefully researched to provide optimum low frequency performance and definition. The cone is suspended at its outer edge by a highly flexible ring to absorb extraneous sound waves within the cone material and allow the long excursion necessary to achieve dynamic range and extend bass response through the lowest registers of the audio spectrum.

 Dividing Network -
The function of a properly designed frequency dividing network is much more complex than simply directing low and high frequency information to the appropriate reproducer. Vitally important to the sound of a loudspeaker system is precise control of the drivers through the transition frequencies. To accomplish this, the tolerances of JBL network components are much more stringent than normal industry practices. The network,installed in the l26 has a continuously variable control permitting adjustment of the relative loudness of the high frequency direct rdiator to satisfy individual preferences and the acoustic properties of the listening room.

Power Capacity
The specified power capacity indicates the continuous program power level that can be accepted by a JBL loudspeaker  system without damage. Its peak power capacity is considerably greater than the continuous rated value, as indicated by the remarkable transient response of JBL loudspeaker system components. The L26 will reproduce clean sound at comfortable listening levels when driven by an amplifier having an output of as little as 10 Watts RMS per channel. However, for reproduction of the full dynamic range of contemporary recordings at high volume, a quality amplifier delivering up to 60 Watts RMS per channel will provide optimum performance. Such an amplifier has the reserve power necessary for accurate reproduction of transients, which can reach momentary peaks equivalent to ten times the average power level. In almost all cases, the volume level generated by a JBL loudspeaker will become noticeably discomforting to the ear before the loudspeaker can be damaged by excessive power from the amplifier.


 Specifications
JBL attributes major importance to the validity of published information.  Rather than repeat the ambiguity of most technical specifications, JBL has traditionally refrained from listing data  for which no widely-accepted test procedure has been established. In the absence of such standards any wellequipped laboratory can legitimately produce a variety of frequency response curves for a loudspeaker, depending on the conditions selected. At JBL the final analyses are comprised of extensive listening sessions. Although laboratory data are an integral part of the process, the trained ear is the ultimate criterion.  The success of this philosophy is reflected in the enthusiastic acceptance of JBL systems by recording studio engineers, producers and performers - professionals whose artistic achievements are closely related to the equipment they use. In every critical listening situation - wherever the sound of the loudspeaker must be depended upon - JBL is the overwhelming professional choice.


Specifications
Power Capacity:  35 Watts continuous program
Nominal Impedance:  8 ohms
Dispersion:  90° horizontal and vertical
Crossover Frequency:  2000 Hz
Efficiency:  76 dB (1 Watt at a distance of 15 feet)
Low Frequency Loudspeaker
Nominal Diameter : 10 inches (250 mm)
Voice Coil : 2 inch (50 mm) copper
Magnetic Assembly Weight : 2,5 pounds (1,1 kg)
Flux Density : 8500 gauss
Sensitivity : 40 dB
High Frequency Direct Radiator
Nominal Diameter : 1,4 inches (36 mm)
Voice Coil : 5/8 inch (16 mm) copper
Magnetic Assembly Weight : 1,6 pounds (0,7 kg)
Flux Density : 15,000 gauss
Sensitivity : 47 dB
Finish: Natural Oak
Grille:  Stretch fabric
Grille Color Options:  orange, Blue, White or Brown
Dimensions:  12-3/4 x 24 x 13-1/4 inch (320 x 610 x 34 mm)
Weight:  41 lbs (19 kg) shipping



1 commento:

  1. I think it is an excellent product, i like to listen to music in my free time. They introduce a lot of products and they launch new products in domestic and global markets. " S700 " It's the latest product of JBL .i like black

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