User manual ART 451

[. . . ] Automatic Relay Bypass The 400 Series of Precision Graphic Equalizers also feature automatic relay bypass of audio, an essential function if power to the unit is lost. Rugged construction and solid audio performance make these equalizers particularly well suited to fixed installation as well as touring live sound systems. Additional Controls and Indicators The 400 Series of Precision Graphic Equalizers utilize a variable input level control, clip level indicator, ground lift switch, and selectable line voltage. Additional features include selectable Scale Switching - (High Slider Resolution +/-6dB - or Normal Resolution (+/-12dB), active balanced and unbalanced input/output connectors, and RFI filtering. [. . . ] In addition to the range selection switch there is an output level control potentiometer. Note: If there is too much gain, your equalizer has a red LED Clip indicator that illuminates when signals are within 4dB of clipping. If the Clip LED flashes occasionally, this is okay, but if this LED is steadily on you must readjust the level control. INITIAL SET UP Here are some tips to help you with the initial set up: 1. Select the Bypass switch to bypass the equalizer (Note: The red LED is on). Set the frequency slide controls to the center detent (or 0dB). 4 4. If you do not have enough equalization control, switch the range switch to the 12dB setting. FRONT PANEL CONTROLS 1. POWER SWITCH To turn the equalizer ON or OFF, press the upper or lower portion of this button. CAUTION: Always turn on your equalizer BEFORE your power amplifiers are turned on, and always turn off your equalizer AFTER your power amplifiers have been turned off. FILTER LEVEL CONTROLS Each of these sliders controls the output level of each of the 31 (or 15) bandpass filters. A detent at the center position helps center the controls for a flat response. FILTER RANGE SWITCH & INDICATORS The gain range of the filter sliders is switchable (as a group) from +/- 6dB to + /-12dB for maximum boost/cut capability. At 6dB the green LED will illuminate, and at 12dB the yellow LED will illuminate. 5 4. BYPASS SWITCH & CLIP INDICATOR LED Bypass Switch: When the red LED is illuminated, this indicates that the unit or channel is in the bypass mode. Signal is routed directly from the input to the output without passing through any circuit (often referred to as "hard-wire bypass"). Use this switch to compare equalized and unequalized material, or to bypass the EQ section in the event of power loss or unit failure. Clip Indicator: - This red LED illuminates if any section of the equalizer is within 4dB of clipping. Occasional flickering of this LED is acceptable, but if it remains on more than intermittently you should turn down either the equalizer's level controls or reduce the output level of the preceding component to avoid audible distortion. HI PASS FILTER (LOW-CUT FREQUENCY CONTROL) To cut down on unwanted low frequency signals, this control determines the roll-off frequency of the High-Pass Filter (HPF). The roll-off frequency can be adjusted from 10Hz to 250Hz by turning this knob. Because of its high roll-off slope, the HPF can be efficiently used to cut down the "HUM" noise from preceding instruments, or to reduce low frequency resonances, when speakers are installed in an enclosed acoustic environment. LOW PASS FILTER (HIGH-CUT FREQUENCY CONTROL) To cut down on unwanted high frequency signals, this control determines the roll-off frequency of the Low-Pass Filter (LPF). [. . . ] Please write down a description of your complete setup before calling Customer Service. 3) Contact our Customer Service department at (585) 436-2720 for your Return Authorization number or questions regarding technical assistance or repairs. Customer Service hours are 9:00 AM to 5:00 PM Eastern Time, Monday through Friday. 5) Include with your unit: a return shipping address (we cannot ship to a P. O. [. . . ]