JBL MS-8 User Manual

Also see for MS-8: User guide Service manual Installing

JBL MS-8 User Manual Manual pdf 26 page image

www.jbl.comOUTPUT SETUPNext, the MS-8 will display Xover Setup. During Xover Setup, you must tellthe MS-8 which speakers are connected to the system, and you must selectthe crossover characteristics for all of the system’s speakers. Referring to theConfiguration Chart that you filled out when you connected the MS-8 will makethis process easy. During Xover Setup and Channel Selection, you must enter theinformation according to the specific sequence that the MS-8’s display presents.A note about crossoversIn general, your car stereo’s small speakers are designed to reproduce high frequencies,while its large speakers are designed to reproduce low frequencies. Larger speakers do apoor job of reproducing high frequencies, and smaller speakers are not able to reproducelow frequencies and may even be damaged by them.A crossover is a filter or combination of filters that limit the sounds that are sent to aparticular speaker so that it receives only the frequencies that it can safely reproduce.The MS-8 features a sophisticated crossover system that you can set to get the bestperformance from whatever type of speaker system is installed in your vehicle.In the MS-8, a crossover (or filter, abbreviated “Xover” on the MS-8 display) frequencyrefers to the frequency at which the sounds sent to that speaker will begin to beattenuated. The crossover filter slope refers to the rate at which the sounds will beattenuated. The MS-8’s crossover contains two types of filters:• High-pass filters, which send the frequencies above the crossover frequency to aspeaker while attenuating the frequencies below the crossover frequency. This type offilter is used to prevent lower frequencies from reaching smaller speakers.• Low-pass filters, which send the frequencies below the crossover frequency to a speakerwhile attenuating the frequencies above the crossover frequency. This type of filter isused to prevent higher frequencies from reaching larger speakers.A high-pass filter can be combined with a low-pass filter to create a third type of filter,called a band-pass filter. A band-pass filter sends the band of frequencies betweenthe high-pass and low-pass crossover frequencies to a speaker while attenuating thefrequencies below the high-pass crossover frequency and above the low-pass crossoverfrequency. This type of filter is used to prevent lower and higher frequencies from reachingmidrange speakers in three-way speaker systems.The most important thing that determines your selection of an MS-8 crossoverfilter’s frequency and slope is making sure that your system’s small speakersdon't receive too much bass, which can cause the sound they reproduce to bedistorted and can even damage them.For example, an 80Hz high-pass filter will remove frequencies below 80Hz from the signalthat the MS-8 sends to a smaller speaker. However, it may not completely remove thosefrequencies; a 6dB per octave filter slope will still allow the speaker to receive 1/4 of thesignal’s power at 40Hz, while a 24dB/octave filter slope will allow the speaker to receivealmost no power at 40Hz and will keep the speaker from receiving too much bass. Werecommend using 24dB/octave slopes between subwoofers and midrangespeakers and between midrange speakers and tweeters.CALiBrATiON/seTUP26