JBL LSR Owner's Manual

Contents

104.4 Low Frequency Adjustments:The low frequency response of the LSR28P canbe adjusted to increase or reduce the output level. Thisis typically done when the system is located near a wallor other boundary surface. With all bass adjustmentswitches off, the unit is set to a 36 dB/octave roll-offwith a maximally flat characteristic.Switch 4 changes the low frequency roll-off toa 24 dB/octave slope, which extends the low frequencycapability, while slightly reducing maximum soundpressure level. This is useful for spoting subsonic dis-tortions that could otherwise go undetected. For exam-ple, extreme low frequency rumble will be visable asmovement of the woofer cone.Switch 5 changes the low frequency roll-off to 36 dB/octave with a 2 dB boost below 150 Hz. If more bass isdesirable in the monitor, this is the position to use. In a typical monitor situation, this position could lead to “BassLight” records as the user compensates in the mixing suite for the extra low end boost.Switch 6 changes the low frequency roll-off to 36 dB/octave with a 2 dB cut below 150 Hz. If required, theLSR28Ps can be used closer to walls or other boundaries. This position reduces the low frequency to compensate forboundary effects caused by this positioning.4.5 High Frequency Adjustments:Switch 7 boosts the high frequencyresponse by 2 dB above 1.8 kHz. This posi-tion is used if the room is extremely dead ormixes translate too bright.Switch 8 cuts the high frequencyresponse by 2 dB above 1.8 kHz. This posi-tion is used if the room is highly reflectiveor mixes translate dull.4.6 LED Indication:A single LED indicator is located onthe front of the LSR28P. In normal opera-tion, this LED will be GREEN. At the onsetof amplifier clipping in either the low or high frequency amplifier, the LED will flash RED. Continual RED flashing ofthis LED indicates that levels should be reduced.Switch 7 On +2 dBSwitch 7 & 8 Off FlatSwitch 8 On -2 dB+2 dB/36 dB Octave0 dB/36 dB Octave-2 dB/36 dB Octave0 dB/24 dB Octave• •••• •••