• .Dual channel 31 band 1/3-octave constant Q graphic equalizer
  • .Revolutionary Dynamic Noise-Reduction capable of restoring up to 20dB S/N ratio
  • .Proprietary Peak Limiter for system protection
  • .Switchable range between ±6dB and ±15dB
  • .Balanced inputs and outputs
  • .XLR, Barrier Strip, and 1/4” TRS connectors
  • .-12dB/+12dB input gain range
  • .18dB/octave 40Hz Bessel Low-Cut filter
  • .Chassis/signal ground lift capability
  • .Four segment LED bar-graph for both Gain Reduction and Output Level
  • .Power-off hard-wire relay bypass with 2-second power-up delay
  • .3U rack space rack-mounted designed.


All UNIKA graphic equalizers are high performance multi-functional units designed to deliver all the flexibility and power that professional users demand.

The NHQ-312 dual channel 31 band Graphic Equalizers is a useful audio signal processing tools in situations where precise frequency control is required across the audible frequency spectrum.

When used with an audio spectrum analyzer the EQs can tune any acoustical environment, from the studio to the concert hall to stop ringing, increase clarity, and flatten the overall frequency response of the environment.

Insert the graphic equalizer between the signal source and the power amplifiers. Adjust the level and equalization as required to yield the desired system response. The long throw faders of the EQs allow very precise settings of the equalization for accurate equalization curves.


For optimum signal-to-noise response, the gain structure of the sound system must be properly set up. Each component of the sound system should be set at its nominal operating level in order to take advantage of the maximum signal-to-noise properties of that element. Loudspeaker amplifiers, as the last element in the chain, should be set only as loud as necessary, in order to avoid inducing unnecessary noise into the system.

All active equalizers, by nature of design, add noise when boosting or cutting that can easily degrade the otherwise acceptable signal-to-noise ratio of a sound system. Drastic equalization can result in a loss of 20dB or more signal-to-noise.

The Dynamic Noise-Reduction was engineered specifically for applications such as this. It provides up to 20dB of noise reduction, thus restoring the dynamic range necessary for even the most demanding professional sound systems. The combination of proper wiring, proper gain structure and The Dynamic Noise-Reduction should render your sound system virtually noise free.


Input Connectors 1/4" TRS, female XLR (pin 2 hot), and barrier terminal strip
Input Type Electronically balanced/unbalanced, RF filtered
Input Impedance Balanced 40kΩ
Unbalanced 20kΩ
Max Input >+21dBu balanced or unbalanced
Output Connectors 1/4" TRS, male XLR (pin 2 hot), and barrier terminal strip
Output Type Impedance-balanced/unbalanced, RF filtered
Output Impedance Balanced 200Ω 
Unbalanced 100Ω
Max Output >+21dBu balanced/unbalanced into 2 kOhm or greater;
>+18dBm balanced/unbalanced (into 600 ohm)
Bandwidth 20Hz to 20kHz, ±0.5dB
Frequency Response <10Hz to >50kHz, +0.5/-3dB
Dynamic Range
(NR In: +/-6dB and +/-15dB ranges)
>120dB, unweighted
Total Harmonic Distortion + Noise <0.04%, 0.02% typical at +4dBu, 1kHz
Inter-channel Crosstalk <-80dB, 20Hz to 20kHz
Noise Reduction Up to 20dB of dynamic broadband noise reduction
Bypass Switch Bypasses the graphic equalizer section in the signal path
Low cut Switch (recessed) Activates the 40Hz 18dB/octave Bessel high-pass filter
Range Switch (recessed) Selects either ±6dB or ±15dB slider boost/cut range
I/O Meter 4-LED bar graph (Green, Green, Yellow, Red) at -10, 0, +10, and +18dBu
Gain Reduction Meter 4-LED bar graph (all Red) at 0, 3, 6, and 10dB
  NR Active (Yellow); EQ Bypass (Red); Clip (Red); Low Cut (Red);
Indicators ±6dB (Yellow); ±15dB (Red)
Operating Voltage 100VAC 50/60Hz; 120VAC 60Hz; 230VAC 50/60Hz
Power Consumption 28W
Power Connector IEC receptacle
Dimensions (H×W×D) 5.25" H X 19" W X 7.9" D
(13.335cm x 48.3cm x 20.1cm)