JBL S4800 Owner's Manual

Contents

The following sections describethe primary features and compo-nents of the S4800 loudspeakersystem.The enclosure of the S4800 isspecially designed to transferunwanted mechanical energyaway from any acoustically activesurfaces, virtually eliminatingcoloration.The massive enclosure, alongwith its specially designed brassmodular feet, couples directly tothe floor, and the system literallybecomes a structural part of itsenvironment. Any vibration istransmitted harmlessly down thechannel provided by the ring/disc axes and into the floor. TheSonoGlass combination hornmaintains a smooth energytransmission path.The S4800 transducer/enclosurearrangement represents the bestpossible balance of the varioustuning options and avoids themid-bass response buildup foundin other vented systems. Responseworks with, rather than against,the effects of “room loading.”The unique design of the systemis the platform for its equallyunique acoustical attributes.Thanks to the combination horn,both the UHF (ultrahigh-frequency)and HF (high-frequency) driversare located at the ear level of thelistener.See Figure 2.The large 3-inch HF transducerallows the 15-inch woofer to becrossed over at a frequency lowenough to eliminate any audibleeffects of its exact location andproximity.Full image coherency is main-tained, resulting in an acousticallystable pinpointed stereo image. Allthe sound seems to come from thecombination horn. Music imagingis more realistic since the soundappears to emanate from one pointand not from multiple points at dif-ferent times.The S4800 is a constant-angle sys-tem without regard to frequency.Careful horn design enables theloudspeaker to strictly adhere to a100° horizontal/60° vertical cover-age pattern. This controlled cover-age arrangement precisely definesthe optimum listening area andminimizes room effects. At thesame time, it provides a generous“sweet spot” for more comfortablecritical listening sessions.THE 1500FE LOW-FREQUENCY DRIVERSee Figure 3.In order to achieve the lowest pos-sible distortion and compressionalong with the high linear excur-sion necessary, the 1500FE isequipped with a ferrite magnet.As with earlier JBL low-frequencydrivers, it utilizes forced-air cool-ing. The entire magnetic structureFigure 2. Height of S4800 speaker system in relation to listener.Terminal Base:Glass-Filled ABS Terminals:Gold-Plated 5-WayBinding PostsMagnet:CeramicBack Plate:Steel SAE-1008Pole Sleeve:High-Purity CopperVoice Coil:Aluminum Ribbon WireES-1350 on High-TempFiberglass FormerCone Body:Special Paper-Pulp CompositeFrame:Cast 380AluminumTrim Ring:NBR RubberSpider Spacer:Extruded Aluminum6063Dust Dome:Paper-PulpCompositeSpiders:Nomex®Pigtail Leads:Silver-PlatedCadmium Copperw/Conex CorePolepiece:Steel SAE-1008Surround:EPDM Foam RubberFigure 3. Cutaway view of 1500FE low-frequency transducer. 5