The HQ231 Dual 31-band Graphic EQ is perfect for any live sound application where there is a high feedback potential including monitor mixes, side-fill cabinets or high powered front-of-house mixes situations.
The HQ231 features ART's proprietary FDC™ (Feedback Detection Circuit), with constant Q circuitry capable of delivering a 3% center frequency accuracy. Professional features like LED level metering, selectable 6dB or 12dB slider 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 switch make it ideal for any professional application or touring system.
== FDC Feedback Detection Circuit ==
FDC (Feedback Detection Circuitry - designed and developed by ART Engineering) instantly illuminates an LED on the corresponding EQ band fader with the greatest sustained signal. The LED indicators can immediately show which band corresponds to the feedback frequency, allowing the sound engineer to reduce gain in that band to quickly kill the feedback while having a minimal impact on the sound of the live program material.
The FDC also acts as a simple spectrum viewer while the concert proceeds showing where the "hot" areas are. During system setup and sound check, the FDC may be used to help identify room and sound system resonances. By increasing the gain until feedback, it is easy to identify those frequencies that are likely to be problems. Reducing the gain in these bands helps tune the sound system, and, remove problem areas before the show begins. It also helps increase the gain margin before feedback.
== Constant-Q Filtering ==
The HQ231 features Constant-Q Filtering, which helps the HQ's FDC work with greater efficiency while offering superior overall performance of the EQ. Constant-Q ensures that even when making radical adjustments to a frequency band, that adjacent bands will not be affected. This is particularly critical in professional applications including monitor mixes and feedback control.
== Professional Feature Set ==
Professional features like 45mm center detent sliders with selectable boost or cut range of 6dB or 12dB ensures the HQ231 can be used for radical tone shaping, or precise control of a sound system. Versatile connection to any live sound system or installation can be easily made using balanced XLR, 1/4-inch TRS and unbalanced RCA input and output jacks included on the HQ231 back panel.
High and low pass filters, analog level metering, variable input level controls, signal clip level indicators, ground lift switch, internal power supply and selectable line voltage complete the HQ231 Dual 31-Band Graphic EQ's full feature set.