JBL LSR Owner's Manual

Contents

5.4 Changing Low Frequency Characteristics:Switch 4 reverses the polarity of the LSR12P. At the crossover point between the subwoofer and satel-lite speakers, it is important that all systems are in the correct polarity. If the subwoofer and the satellitewoofers are in the same vertical plane, the polarity should be set to normal. If the subwoofer is not in thesame plane as the satellites, the polarity might need to be reversed. To check this, put on a track that has agood amount of bass and switch between the two positions. The setting that produces the most bass should bethe one to go with.The low frequency response of the LSR12P can be adjusted to compensate for room placement. Bassfrequencies below 80-90 Hz are essentially omnidirectional. Positioning subwoofers in corners or against wallswill increase the in-room efficiency of the system allowing greater apparent output. Placing subwoofersagainst wall boundaries will also reduce frequency response variations due to cancellation interference. Thesebass adjustment switches compensate for location by adjusting the amount of low frequency energy generatedbelow 50 Hz.A technique that has been used successfully is to put the subwoofer in the listening position andmove the mic or yourself into possible subwoofer locations. Finding the positions with the best low frequencyenergy can quickly be found. After you find a couple of possibilities, move the subwoofer into one of theselocations and evaluate.Switch 5 reduces the level below 50 Hz by 2 dB. This position is designed to offer maximally flatresponse when the LSR12P is placed at the intersection of two boundaries such as a floor and wall.Switch 6 reduces the level below 50 Hz by 4 dB. This position has been designed to offer maximallyflat response when the LSR12P is placed at the intersection of three boundaries such as a corner location.5.5 Bypass and Discrete Operation:The 1/4” jack used for bypass and discrete selection operates with a simple dry contact closurebetween the tip and sleeve of the jack. This function can also be initiated with an opto-isolated electronicclosure shorting the two contacts together. The sleeve of this connector is tied to audio ground so care shouldbe taken to avoid ground loops when using this option.13ON115V