JBL S4800 Owner's Manual

Contents

The S4800 has an HF trim switchmounted on the network panelon the rear of the enclosure. TheHF Trim Switch £ adjusts thehigh-frequency level over therange of approximately 1000Hz to10kHz. The +1dB position gives thehighest HF output and measuresthe most level. 0dB reduces the HFlevel by 1dB, and the –1dB positionreduces the HF level by an addi-tional 1dB.Although the range of these controlsettings is rather small, each ofthem operate over a reasonablywide frequency range and thushave a noticeable effect on theoverall tonal balance of the system.It is recommended that the systemfirst be played with the switch inthe middle position. This settinggives the most uniform measure-ments in a controlled environment.Of course, we are interested in pro-ducing the most pleasing sound inyour environment with your choiceof program material. It is, therefore,recommended that the HF TrimSwitch £ be tested in its varioussettings on a variety of programmaterial. Once you become familiarwith their individual character, youshould have no difficulty determin-ing the setting that produces themost pleasing, natural sound inyour room with your equipment.¡ Mid-/High-Frequency InputTerminals: For bi-wire configura-tions, connect the speaker wiresfor the mid- and high-frequencyranges to these terminals.™ Shorting Straps: Leave theshorting straps in place only ifyou are using the passive single-wire connection option describedon page 13. Otherwise, removethe straps to prevent possibledamage to the speakers or yourelectronics.£ HF Trim Switch: This switchallows you to adjust the output ofthe high-frequency transducers tocompensate for the acoustics ofyour room. The +1dB positionincreases the output, the 0dBposition is a flat-level position,and the –1dB position decreasesthe output. Each position willaffect the tonal balance overa wide frequency spectrum.Experiment by placing the switchin each position while listeningto familiar program material andchoose the position that suitsyour room acoustics and listeningpreferences. You may find after afew months, once the transduc-ers have settled in, that anotheradjustment is necessary. Thisis normal. The switch may beadjusted using a flat-head screw-driver.¢ Low-Frequency InputTerminals: For bi-wire configura-tions, connect the speaker wiresfor the low-frequency range tothese terminals.CHAPTER 6 – S4800 SWITCH OPERATIONS11CONTROLS ANDCONNECTIONS¡™™£¢Model S4800HF - UHFINPUTHF - TRIMLFINPUTJBL Incorporated, Northridge, California USA+1dB+0dB–1dB–– +Figure 8. S4800 controls and connections.