User’s Guide for the LS4 24dB/Octave Active Stereo Crossover In order to achieve the highest level of performance from your crossover, please read this owners guide prior to its use.
LS4 24dB/Octave Active Stereo Crossover Congratulations on the purchase of your new Crate Pro Audio LS4 Crossover. This outstanding device has been designed with the audio professional in mind, providing the degree of accuracy and level of quality you demand. Its straight-forward design and simple operation make it easy to use by novices as well.
LS4 24dB/Octave Active Stereo Crossover The Front Panel: 1,12 - INPUT: This control adjusts the level of the input signal to accommodate a wide variety of sources. The Input control should be set so the Peak LED (#2,#13) flashes occasionally during strong peak-level signals. The control functions as follows: Stereo Mode: #1 controls the input level for Channel 1 and #12 controls the input level for Channel 2. Mono Mode: The input signal level is controlled only by #1.
LS4 24dB/Octave Active Stereo Crossover The Rear Panel: 22 - POWER JACK: Plug the small end of the AC adapter into this jack. Plug the other end of adapter into a suitable source of the proper AC voltage, as indicated on the adapter. Use only the supplied 10VAC, 1400mA adapter. 23 - POWER SWITCH: Use this switch to turn the crossover on and off.
LS4 24dB/Octave Active Stereo Crossover The Low Cut and High Cut Switches: The Low Cut switch (#3,#14) provides a 6dB/octave cut in the amplitude of signals below 40Hz to eliminate subsonic rumble. The High Cut switch (#4,#15) provides a 6dB/octave cut in the amplitude of signals above 15kHz to reduce hiss and other unwanted high frequency noise. These circuits are engaged when their respective switches are depressed. The chart below illustrates the effect these switches have on frequency response.
LS4 24dB/Octave Active Stereo Crossover The CD Horn EQ Switch: The CD Horn EQ switch (#9,#20) allows the user to boost the upper frequencies by 12dB to compensate for Constant-Directivity horns. The chart below illustrates the effect of this switch. How to Use the Crossover: With a Subwoofer: Adding a subwoofer requires an additional power amplifier and a couple of cables. The basic connections are illustrated below. 6 Connect the line level output of your source (mixer, preamp, etc.
LS4 24dB/Octave Active Stereo Crossover How to Use the Crossover (con’t): With a Subwoofer (con’t): Before turning the amplifiers on, you will need to set up the crossover. First, set the Input level to “10” (full clockwise). Set the Frequency control to properly match the spatial relationship between the subwoofer and upper range cabinet. For the subwoofer, the frequency will be low, so make sure the X1/X10 switch is OUT. Start with the Frequency control at 50Hz, then adjust as needed.
LS4 24dB/Octave Active Stereo Crossover How to Use the Crossover (con’t): With a Subwoofer (con’t): Now you are ready to adjust the output levels. The easiest way to balance your system is to look at the manufacturer’s specifications of your speaker enclosures. Most manufacturers will give a sensitivity spec in terms of one watt input power at a distance of one meter.
LS4 24dB/Octave Active Stereo Crossover How to Use the Crossover: For Bi-Amping in a Single Enclosure: IMPORTANT NOTE: Whether you are bypassing the internal passive crossover of an existing enclosure or building your own system, care must be taken not to exceed the limitations of the speaker components! For bi-amping in a single enclosure, the basic connections are illustrated below. Connect the line level output of your source (mixer, preamp, etc.) to the CHANNEL ONE BALANCED INPUT of the LS4 (A).
LS4 24dB/Octave Active Stereo Crossover How to Use the Crossover (con’t): For Bi-Amping in a Single Enclosure (con’t): The dispersion characteristics of a typical speaker and horn are illustrated below: This chart illustrates different diameter cone loudspeakers and their typical dispersion characteristics: As previously stated, system balance is very important.
LS4 24dB/Octave Active Stereo Crossover How to Use the Crossover (con’t): For Bi-Amping in a Single Enclosure (con’t): Use of a signal delay processor may be necessary to correct the time alignment of the components: For Tri-Amping: IMPORTANT NOTE: Whether you are bypassing the internal passive crossover of an existing enclosure or building your own system, care must be taken not to exceed the limitations of the speaker components! The LS4 features a 3-way mono mode that can be activated by pressing in
LS4 24dB/Octave Active Stereo Crossover Technical Specifications Filter Type Two 24dB/octave Linkwitz-Riley state variable filters Control Range 50 - 1kHz (X1) 500 - 10kHz (X10) 3-Way Mono Mode Operation Internally Wired Input Impedance10k ohms Input Connections Balanced XLR & 1/4” T/R/S Output Impedance 2.2k ohms Output Connections 1/4” T/R/S Input Gain 0dB @ “10” Output Gain (all Outputs) 6dB Maximum Input Level Accepted +21dBm (0dB = 0.775V rms) Maximum Output Level +21dBm (0dB = 0.
