User manual JBL 830

[. . . ] A hallmark in design, engineering and performance, the DD55000 set the stage for the team's Project K2 S9500 in 1990 and its successor, the K2 S9800, in 2001. "With Project Everest 830, we were seeking the perfect balance between the enclosure design and the acoustical vision. " Daniel Ashcraft Project Everest 830 Cherry Project Everest 830 Exterior Handcrafted in Your Choice of the Finest Veneers Project Everest 830 RW Rosewood · Real Wood Veneer · Cabinet: Rosewood · Woofer Baffle: Black Leather · Grille Cloth: Grey Project Everest 830 CH Cherry · Real Wood Veneer · Cabinet: Cherry · Woofer Baffle: Black Leather · Grille Cloth: Grey Project Everest 830 EB Ebony · Real Wood Veneer · Cabinet: Ebony · Woofer Baffle: Black Leather · Grille Cloth: Grey Project Everest 830 MA Maple · Real Wood Veneer · Cabinet: Maple · Woofer Baffle: Cashmere Leather · Grille Cloth: Light Grey Project Everest 830 System Design An Augmented Two-Way System ­ Because Integration Is Everything "A properly designed two-way speaker is the ideal loudspeaker. " ­ Project Everest 830 was developed by JBL Chief Engineer Greg Timbers to demonstrate the truth of this simple statement. A bass driver and a high-frequency compression driver cover the entire audible range. An additional woofer handles the extreme low end and a second compression driver acts as a super-tweeter. [. . . ] All components are carefully integrated to achieve an imperceptible transition from the deepest notes to ethereal highs with incredibly flat response. At any frequency and volume level, linearity is maintained to deliver all musical information in a consistent timbre. Music floats freely, as technology and loudspeakers seem to disappear. Project Everest 830 Chief Engineer Greg Timbers (Chief Engineer, JBL) "The 830 system, like many before it, is comprised of the finest components, a truly stunning visual design and top-notch craftsmanship. All the system knows how to do is make beautiful music. While it delivers every bit of content and detail incorporated in the original recording, it does so with passion. Never before in my history in the hi-fi industry have I come across a system that is so competent at being a conduit for music as opposed to being just a loudspeaker. " Greg Timbers Project Everest 830 Rosewood Basic Configuration Project Everest 830 is an augmented two-way speaker system, a classic JBL design. One 380mm (15") woofer crosses over to a horn-loaded compression driver at 700Hz, the midpoint of the audio spectrum. A second 380mm woofer reinforces bass from below 30Hz to 150Hz, while an ultrahigh-frequency driver operates exclusively in the supersonic realm above 20kHz. The choice of crossover points minimizes the sonic degradation that can be caused by even a high-quality dividing network. The woofers are phased to achieve uniform directivity across their entire operating range, greatly enhancing low-end realism. With unparalleled dynamic linearity and harmonic distortion levels approaching those of a fine amplifier, we know of no loudspeaker system better able to realistically reproduce the subtlest nuances of any musical source. in order to support the dual 380mm woofers. This fully vented frame and motor design also serves to minimize the back pressure under the dome and spider, helping to reduce harmonic distortion to even lower levels. Taken together, the cutting-edge technologies of the 1501AL reduce harmonic distortions at both high and low acoustic outputs, reduce power compression and deliver a more consistent spectral balance, regardless of input levels. Perhaps most important for people who prefer their music at concert-level volumes, power handling is improved by as much as 25% over earlier low-frequency drivers. Dual inverted Nomex® spider Alternating steel/copper gat rings Die-cast aluminum motor housing Polepiece Aluminum conductive ring Back plate Alnico 5DG magnet Paper-pulp composite cone Foam rubber surround 100mm Edgewound voice coil Die-cast aluminum frame Aquaplas damping material 1501 AL Low-Frequency Driver 476Be High-Frequency Driver With a 100mm (4") pure-beryllium diaphragm, a 100mm (4") aluminum edge-wound voice coil and a rapid-flare, coherent-wave phase plug, the 476Be high-frequency driver delivers astonishing high-end performance with minimal distortion and power compression, even at the highest output levels. The diaphragm is formed of pure beryllium foil, manufactured with a proprietary high-temperature, pressure-forming process. This process enables the integrated JBL diamond-pattern surround to be formed as one piece with the dome. Compared to other methods, forming the diaphragm out of sheets of beryllium foil yields greater reliability and resistance to failure due to fatigue. Pure beryllium has proven to be superior to aluminum, magnesium, titanium and other premium diaphragm materials. Because of its far greater stiffness-to-density ratio, it responds to the highest frequencies with more precise and consistent pistonic action and resists modal breakup better than any other widely used material. In place of a conventional copper-plated polepiece, the 476Be combines a powerful neodymium rare-earth motor structure with an innovative, high-purity copper-sleeved polepiece to maintain gap flux and significantly enhance electrical conductivity without compromising on size and weight. Better conductivity directly translates into lower coil inductance, more effective heat dissipation, reduced dynamic power compression and greater output at frequencies of 15kHz and above. The 476Be's unique coherent-wave phasing plug is precision-diecast of zinc to ensure dimensional and structural stability under high heat and acoustic pressure. [. . . ] The four-slot coherent-wave design shapes the wave output to deliver a true coincident wave front to the Bi-Radial® horn, producing exceptionally smooth frequency response and reducing secondary harmonic distortion by up to 6dB, relative to earlier designs. Neodymium magnet Top plate Foam damping pad Beryllium diaphragm assembly Acoustic seal 045Be-1 Ultrahigh-Frequency Driver With a 25mm (1") pure-beryllium diaphragm and 50mm (2") neodymium magnet structure, the ultrahigh-frequency 045Be-1 is considerably smaller than the high-frequency 476Be. The pure-beryllium diaphragm is less than 0. 04mm thick and has a mass of only 0. 1 gram. The single-layer aluminum-ribbon voice coil is wound without a former and is attached directly to the diaphragm. The driver employs the smallest annular-slit phasing plug that JBL has ever designed. [. . . ]