User manual JL AUDIO 450-4

[. . . ] JL AUDIO 450/4 four-channel system amplifier o w n e r 's m a n u a l Thank you for purchasing a JL Audio amplifier for your automotive sound system. Your amplifier has been designed and manufactured to exacting standards in order to ensure years of musical enjoyment in your vehicle. For maximum performance and extended warranty coverage, we highly recommend that you have your new amplifier installed by an authorized JL Audio dealer. Your authorized dealer has the training, expertise and installation equipment to ensure optimum performance from this product. [. . . ] C) Subwoofer Level Control Only Required: a source unit or processor with left, right and subwoofer outputs. Input Connections: the main stereo pair of source unit outputs is connected to the CH 3&4 inputs of the 450/4. The source unit's dedicated subwoofer output is connected to the CH 1&2 inputs (select "4ch" on the "Input Mode" switch in the "CH 1&2 Input Section"). Result: in this mode, the user has the ability to control the absolute level of the LF channels relative to the HF channels. Crossover Setup for Bi-Amplified System with one 450/4: Once the input sections have been configured appropriately, go to the "CH 1&2 Filter Section". Select "x1" on the "Freq. Range" switch, "LP" (lowpass) on the "Filter Type" switch and "12dB" or "24dB" on the "Filter Mode/Slope" switch and an appropriate "Filter Freq. " (80-90 Hz is a good starting point). You may also choose to activate the "Infrasonic Filter" and/or "Bass EQ" features in the "CH 1&2 Bass Control" section. Please keep in mind that activation of the "Bass EQ" may require lowering the CH 1&2 "Input Sens. " to maintain clean maximum output. Next, turn your attention to the "CH 3&4 Input Section" and select "x1" on the "Freq. Range" switch, "HP" (high-pass) on the "Filter Type" switch and "12dB" or "24dB" on the "Filter Mode/Slope" switch and an appropriate "Filter Freq. " (again, 8090 Hz is a good starting point). After proper adjustment of the CH 1&2 and CH 3&4 "Input Range" and "Input Sens. " controls using the method shown in Appendix B (page 20), you can fine tune filter frequencies and slopes and attenuate either pair of channels to achieve proper balance. For precise filter frequency information refer to Appendix A (page 20). BI-AMPLIFIED SYSTEM WITH ONE 450/4 IN FOUR-CHANNEL MODE AND A SEPARATE SUBWOOFER AMPLIFIER This configuration requires that the separate subwoofer amplifier has a built-in low-pass filter. All JL Audio subwoofer amplifiers have this feature. In this configuration, CH 1&2 of the 450/4 will drive front component speakers (stereo 150W x 2) with high-pass filtering. CH 3&4 will drive rear component speakers in stereo (75W x 2) with highpass filtering. The separate amplifier will drive the subwoofer system with low-pass filtering (select a filter frequency of 80-90 Hz to start). The inputs of the subwoofer amplifier may or may not be connected to the preamp outputs of the 450/4, depending on which connection option you choose. Input connection options for a bi-amplifier system with one 450/4 and a separate subwoofer amplifier are as follows: A) No User Adjustability Required: a basic source unit or processor with left and right stereo outputs. Input Connections: a single pair of stereo source unit outputs is connected to the CH 1&2 inputs of the 450/4 (select "2ch" on the "Input Mode" switch in the "CH 1&2 Input Section"). Connect the subwoofer amplifier inputs to the preamp outputs of the 450/4 (Select "1&2" on the "Signal From" switch in the "Preamp Output Section"). Result: the relative level of the LF and front and rear HF channels will be fixed by the 450/4's "Input Sens. " settings and will not be user adjustable from the front of the vehicle. HF Level Required: a source unit or processor with front and rear pairs of stereo outputs. Input Connections: one stereo pair of source unit !I M P O RTA N T Set the CH 1&2 "Input Sens. " with the source unit's subwoofer level control set at 3/4 of full output. [. . . ] Due to ongoing product development, all specifications are subject to change without notice. DIMENSIONS: (LxWxH): 19. 7" x 9. 25" x 2. 36" (500mm x 235mm x 60mm) PREAMP OUTPUT: 2-Channel pass-through type, switch-selectable to pass signal from CH 1&2 inputs only, from CH 3&4 inputs only or from all four inputs (summed). CHANNELS 3&4: Amplifier Topology: Class AB with patented Absolute SymmetryTM dual N-Channel MOSFET output design Power Supply: Independent, pulse width modulationregulated switching power supply with multistage impedance optimizing circuitry. Rated Power (Stereo): 75W RMS x 2 @ 1. 5 - 4 (11V - 14. 5V) Rated Power (Bridged): 150W RMS x 1 @ 3 - 8 (11V - 14. 5V) THD at Rated Power: <0. 03% @ 4 per channel (20 Hz - 20 kHz) Signal to Noise Ratio: >108. 5 dB referred to rated power (A-weighted, 20 Hz - 20 kHz noise bandwidth) Frequency Response: 5 Hz - 30 kHz (+0, -1 dB) Damping Factor: >200 @ 4 per ch. [. . . ]