dbx 1231 - Dual-Channel 31-Band Graphic Equalizer with Switchable 6 or 15 dB Boost/Cut Ranges and RF Filtered Inputs/Outputs in Black Finish

The dbx 1231 Dual-Channel 31-Band Graphic Equalizer stands out as a premium choice for those demanding the highest quality in sound reinforcement. It is part of the dbx 12 Series, designed to deliver robust performance with straightforward controls, making it an excellent fit for a variety of audio applications. The 1231 features dual channels, each equipped with 31 1/3 octave bands, enabling precise frequency adjustments to tailor the sound to perfection. Its ISO frequency centers and ±12 dB input gain range offer comprehensive control over the audio signal.

One of the key attributes of the dbx 1231 is its selectable boost/cut range, which allows users to choose between ±6 dB or ±15 dB adjustments. This flexibility ensures that users can make fine-tuned changes or more pronounced alterations to the audio signal as needed. The equalizer is equipped with 45 mm faders for accurate and responsive control, and includes switchable 40Hz/18 dB per octave low-cut filters to effectively remove unwanted low-frequency rumble.

The dbx 1231 is designed with various connectivity options for ease of installation and integration. It includes XLR, barrier strip, and 1/4" TRS connectors, all providing balanced and unbalanced input and output options. The inputs and outputs are RF filtered to minimize interference, ensuring clean and clear audio performance. The unit also features chassis and signal ground lift capabilities, allowing for quick isolation of hum and ground loop issues.

Durability and reliability are key considerations in the design of the dbx 1231. It is housed in a rugged 3U steel and aluminum chassis, and incorporates a magnetically isolated transformer along with power-off hardwire relay bypass with a 2-second power-up delay. This design helps protect the unit and connected equipment during power cycles. The internal power supply transformer supports a range of operating voltages, including 100VAC, 120VAC, and 230VAC, with a power consumption of 24 watts.

In terms of performance, the dbx 1231 excels with a frequency response that extends from <10Hz to >50kHz, maintaining accuracy across a broad spectrum of audio frequencies. The unit boasts a dynamic range of 109 dB to 115 dB, a signal-to-noise ratio of 90 dB to 97 dB, and a total harmonic distortion plus noise (THD+Noise) of less than 0.005%. Additionally, interchannel crosstalk is minimized to less than -80 dB from 20Hz to 20kHz, ensuring high-quality audio separation and clarity.

The front panel of the 1231 features intuitive indicators and controls. A 4-LED bar graph displays the output level at -10, 0, +10, and +18 dBu. LEDs also indicate EQ bypass status, clip detection, low cut filter activation, and the selected boost/cut range. Recessed function switches allow users to activate the EQ bypass, low cut filter, and adjust the boost/cut range with ease.

Overall, the dbx 1231 Dual-Channel 31-Band Graphic Equalizer is a sophisticated and reliable tool designed to meet the rigorous demands of professional sound reinforcement, offering exceptional performance, flexibility, and ease of use.

Features

• Dual-channel 31-band graphic equalizer with 1/3 octave bands
• Selectable ±6 dB or ±15 dB boost/cut range for flexible adjustments
• 45 mm faders for precise control
• Switchable 40Hz/18 dB per octave low-cut filters to eliminate low-frequency noise
• RF-filtered inputs and outputs to minimize interference
• Versatile connectivity: XLR, barrier strip, and 1/4" TRS connectors
• Electronically balanced/unbalanced inputs and servo balanced/unbalanced outputs
• Chassis/signal ground lift capability for quick hum isolation
• Internal power supply transformer with power-off hardwire relay bypass and 2-second power-up delay
• Frequency response from <10Hz to >50kHz, ±0.5/-3dB
• Dynamic range of 109 dB to 115 dB
• Signal-to-noise ratio of 90 dB to 97 dB
• Total harmonic distortion plus noise (THD+Noise) <0.005%
• Interchannel crosstalk < -80 dB from 20Hz to 20kHz
• Front-panel indicators for output level, EQ bypass, clip, low cut, and boost/cut range
• Dimensions: 19 x 7.9 x 5.25 inches
• Weight: 10.6 lbs; Shipping weight: 11.6 lbs

Specifications

Inputs

• Connectors: 1/4" TRS, female XLR (pin 2 hot), and barrier terminal strip
• Type: Electronically balanced/unbalanced, RF filtered
• Impedance: Balanced 40kΩ, unbalanced 20kΩ
• Max Input Level: >+21dBu balanced or unbalanced
• CMRR: >40dB, typically >55dB at 1kHz

Outputs

• Connectors: 1/4" TRS, male XLR (pin 2 hot), and barrier terminal strip
• Type: Impedancebalanced/unbalanced, RF filtered
• Impedance: Balanced 200Ω, unbalanced 100Ω
• Max Output Level: >+21dBu balanced/unbalanced into 2kΩ or greater, >+18dBm balanced/unbalanced (into 600Ω)

System Performance

• Bandwidth: 20Hz to 20kHz, +0.5/-1dB
• Frequency Response: <10Hz to >50kHz, +0.5/-3dB, +/-15dB range +/-6dB range
• Dynamic Range: 109db 115db
• Signal-to-Noise: 90db 97db
• THD+Noise: <0.005%
• Interchannel Crosstalk: <-80dB, 20Hz to 20kHz

Function Switches

• EQ Bypass: Bypasses the graphic equalizer section in the signal path
• Low Cut (recessed): Activates the 40Hz 18dB/octave Bessel highpass filter
• Range (recessed): Selects either +/- 6dB or +/- 15dB slider boost/cut range

Indicators

• Output Level: 4-LED bar graph (Green, Green, Yellow, Red) at -10, 0, +10, and +18dBu
• EQ Bypass: 1 LED: red
• Clip: 1 LED: red
• Low Cut: 1 LED: red
• +/-6dB: 1 LED: yellow
• +/-15dB: 1 LED: red

Power Supply

• Operating Voltage: 100VAC 50/60Hz, 120VAC 60Hz, 230VAC 50/60Hz
• Power Consumption: 24W
• Mains Connection: IEC receptacle

Physical

• Dimensions: 19 x 7.9 x 5.25 inches
• Weight: 10.6 lbs
• Shipping Weight: 11.6 lbs