JBL S4800 Owner's Manual

Contents

is attached to a die-cast alu-minum-alloy frame. This providesaccurate, rigid support for themotor and cone mounting points,as well as doubling as a massiveheatsink by providing a huge sur-face area for heat dissipation.The 1500FE has a central coolingduct that effectively cools thevoice coil and reduces the likeli-hood of hot spots. By reducing theoperating temperature of the voicecoil, power compression is signifi-cantly reduced, which enables thelow-frequency driver to operate ina more linear fashion over a widersound pressure level (SPL) range.The voice coil itself is constructedfrom edge-wound aluminum wireon a massive 4-inch-diameterfiberglass former. This configura-tion provides for further coolingability in conjunction with themotor design.The Aquaplas-coated, Kevlar-composite cone, along with theEPDM rubber surround, providesexcellent damping and transientresponse characteristics.435AL ALUMINUMDIAPHRAGM/NEODYMIUM MAGNETHIGH-FREQUENCYCOMPRESSION DRIVERSee Figure 4.The 435AL neodymium high-frequency compression driver isbased on the professional JBL 2430device. It incorporates a rare-earthneodymium magnet structure,designed by extensive computermodeling, including finite elementanalysis, which combines theattributes of efficiency, strength,low mass and compact size. Thismotor structure is coupled witha 3-inch aluminum diaphragm.Aluminum provides improved low-distortion characteristics and flatfrequency response.High-temperature materials andadhesives allow the driver to han-dle extremely high power levelsover extended periods of time. TheSonoGlass horn is acousticallyinert and precision-molded toexacting tolerances.Phase PlugAluminumEdge-WoundVoice CoilNeodymiumMagnetAluminum-Alloy Cover3" (75mm)Pure-AluminumDiaphragmBinding-Post InputTerminalFigure 4. Cutaway view of 435AL high-frequency transducer.6