441 DUAL CHANNEL 15 BAND 2/3 OCTAVE GRAPHIC EQUALIZER 451 SINGLE CHANNEL 31 BAND 1/3 OCTAVE GRAPHIC EQUALIZER 455 DUAL CHANNEL 31 BAND 1/3 OCTAVE GRAPHIC EQUALIZER The new ART 400 Series of Precision Graphic Equalizers have been designed and engineered to exceed extremely high standards for audio performance and functionality. These innovative, high-quality equalizers are perfect for virtually any audio application where precision frequency tailoring, reliable performance, rugged design and extremely silent processing is of the utmost priority. Active Filter Sections The 400 Series of Precision Graphic Equalizers feature active filter sections, which incorporate a constant-Q design. This constant-Q design, with accurate precision center frequencies, ensures that the bandwidth of every individual filter will be narrow enough to prevent unnecessary interaction between filters, yet still create an equalization curve wide enough to produce the exact and precise processing of audio frequencies the user seeks. Precision Slide Potentiometers The 400 Series of Precision Graphic Equalizers utilize two x thirty-one 20mm oil-damped precision slide potentiometers. These center-detented, precision faders are graphically positioned at 1/3octave ISO frequencies between 25Hz-20kHz. Independent Variable Hi and Low Pass Filtering In order to deliver superlative performance and control, the 400 Series of Precision Graphic Equalizers incorporates independent variable Hi Pass (low cut) and Low Pass (high cut) filters. Having separate and variable precision control for both the Hi Pass and Low Pass filters allow the user to custom tailor the audio signal to perfection. Many competing products only feature shelving switches which have a fixed frequency point. Others do not have separate filtering for both high and low frequencies. These designs do not offer the precision or control of an ART 400 Series equalizer. 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. A passive Bypass switch allows for direct comparison between the equalized and non-equalized signal for each channel. Multiple Connectivity The 400 Series of Precision Graphic Equalizers are connectable with a wide variety of audio devices and each unit has three sets of input and output connectors wired in parallel. These connections include XLR, 1/4" phone, and RCA phono connectors. Durability by Design The 400 Series of Precision Graphic Equalizers are designed and engineered to be durable and rugged. They are an ideal choice when the need for a robust equalizer is of paramount concern, are designed for mounting in a standard 19" equipment rack or one of the many rack type portable cases in existence. The vertical height is 1.75 inches for the 441 and 451, and 3.5 inches for the 455. The depth is 7 inches. Precision and Quality When considering quality equalization, the ART 400 Series of Precision Graphic Equalizers are an excellent choice. They deliver extremely precise, powerfully flexible and simply great sounding equalization, with the quality features and reliable design criteria necessary for top-level audio performance. 2 GENERAL INFORMATION Congratulations on the purchase of your new ART equalizer. This professional equalizer is perfect for virtually any audio application where frequency tailoring is needed. It's features include: constant Q circuitry with accurate center frequencies, selectable 6dB or 12dB range, active balanced and unbalanced input/output connectors, RFI filters, independent variable Hi Pass (low cut) and Low Pass (high cut) filters, variable input level control, passive bypass switch, clip level indicator, ground lift switch, and selectable line voltage. The unit also features automatic relay bypass of audio 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. INSTALLATION This series of equalizers are designed for mounting in a standard 19" equipment rack or one of the many rack type portable cases available on the market. The vertical height is 1.75 inches for the 441 and 451, and 3.5 inches for the 455. The depth is 7 inches. POWER CONNECTORS These equalizers have internal power supplies and are designed for operation from 120 or 240 volt, 50-60Hz mains supply. Power consumption is 7.5 watts. In new installations and portable sound systems, or any situation where the mains power is in question, it is wise to confirm the voltage and select the appropriate line voltage setting BEFORE connecting the equalizer to power sources. INPUT/OUTPUT CONNECTIONS The 400 series graphic equalizers have 3 sets of input and output connectors wired in parallel: XLR, 1/4" phone, and RCA phono connectors. Only one of the 3 inputs should be used per channel. Any combination of output connectors may be used. XLR connections are balanced where pin 2 is High (+), pin 3 is Low (-), and pin 1 is ground. 1/4" Phone connections may be used balanced or unbalanced. When balanced, the tip is High (+), the ring is low (-) and the sleeve is ground. To use unbalanced use a mono phone cable, this will automatically ground the ring to the sleeve. RCA connections are always unbalanced. 3 SIGNAL LEVELS Signal levels from -10 dBu to +4 dBu are considered normal with maximum levels of approximately +19dBu. Do not connect microphones directly to the equalizer. Microphones require a preamp. CHASSIS GROUNDING The equalizers are equipped with a rear panel Ground lift switch. After setting up your system, if the system exhibits excessive hum or buzzing, the problem may be a ground incompatibility between your equalizer and other equipment in the same system. There are several combinations that can be tried. NOTE: ALWAYS TURN YOUR AMPLIFIERS DOWN BEFORE CHANGING GROUNDS. Try different combinations of lifting grounds on units that are supplied with ground lift switches or make sure all chassis are connected to earth ground, either through the AC Power cord ground or by the front panel rack mount screws. If the 400 series equalizer is mounted in a grounded rack of equipment, the ground to the case of the equalizer may be lifted to prevent multiple ground paths, which may cause a ground loop to occur. OPERATING INSTRUCTIONS Before starting to equalize your sound system there is some information you should know and procedures you should follow. Your equalizer is equipped with a bypass switch. The bypass switch, when activated, lights the LED and cancels all equalization settings while allowing signal to flow through the unit at unity gain. Also included is a range selection switch with LED indicators, 6dB =green, 12dB= yellow. In addition to the range selection switch there is an output level control potentiometer. The level control operates between off and +6dB. 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. Set channel levels to the center detent 0dB on the front panel. 2. Select the Bypass switch to bypass the equalizer (Note: The red LED is on). 3. Set the frequency slide controls to the center detent (or 0dB). 4 4. Select the 6dB range switch (Note: The green LED is on). 5. Apply signal to the system. 6. Release the bypass switch (Note: The red LED is off). 7. If the Clip LED is on, you must turn down the input level control. 8.You may now start equalizing your system. 9. 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. 2. 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. 3. 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. 5. 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. 6. 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). The roll-off frequency can be adjusted from 3kHz to 40kHz by turning the knob. Because of its high roll-off slope, the LPF can be effectively used to cut down the high frequency noise from preceding instruments, or roll-off excessive high frequency sounds to obtain a more natural sound in some acoustic situations. 7. LEVEL CONTROL This controls the level of signal coming into the equalizer. Turn this control down if the Clip LED illuminates steadily (meaning too strong an input signal). Unity gain can be set by turning this knob to the center detent position. Signal levels should be kept normalized through the equalizer. That is, the signal level, when bypassed, should be the same (or a little lower) than when active. The reason for this is if the equalizer loses power (which causes the unit to go into bypass), the signal will be equal or lower than the active eq gain. This will ensure that a signal with undesirably higher levels will not be passed inadvertently. 6 REAR PANEL CONNECTORS & CONTROLS 8. POWER CORD This cord is used connect the AC power source to your equalizer. CAUTION: Equipment for USA installation includes a power cord with a three pin polarized plug. DO NOT REMOVE THE CENTER GROUNDING PIN. 9. FUSE HOLDER This fuse holder contains the AC primary fuse. This fuse should be replaced with the same type fuse if it is blown. If they continuously blow, stop replacing fuses and refer servicing to qualified personnel. CAUTION: After checking the AC supply voltage, be sure that the correct fuse is in the fuse holder 0.5Amp for 95-125VAC, as well for 220-240VAC. 10. AC VOLTAGE SELECTOR Set this slide switch to match your line voltage supply. CAUTION: For new installations and portable sound systems, or any situation in which the mains power is suspect, it is wise to confirm appropriate voltage and line polarity BEFORE connecting the instrument to power source. 11. GROUND LIFT SWITCH This switch is used to disconnect signal ground from the mains and chassis earth ground. You may set the switch to the LIFT position if "Hum", caused by a ground loop, can be heard at the speakers. 7 12. INPUT/OUTPUT CONNECTORS 1/4 TRS The TRS (Tip Ring Sleeve) connector is balanced and wired as tip = Hi (+), Ring = Lo (-), and Sleeve = Ground. CAUTION: Only one of these sockets should be chosen for audio connection at the same time. XLR The XLR input connector is balanced and wired as Pin 2=Hi (+), Pin 3=Lo (-), and Pin ...