dbx 131s Single-Channel 31-Band Graphic Equalizer

The dbx 131s is a professional single-channel, 31-band graphic equalizer designed for precise frequency control in live sound reinforcement, recording studios, touring systems, and permanent audio installations. Featuring 1/3-octave Constant Q filtering, the 131s allows sound engineers to fine-tune individual frequency bands for improved tonal balance and system performance.

With switchable ±6 dB or ±12 dB boost/cut ranges, the dbx 131s provides flexibility for subtle sound adjustments or more extensive frequency correction. Its 20mm nonconductive sliders offer straightforward hands-on operation, while the ±12 dB input gain control helps maintain appropriate signal levels.

The equalizer includes a switchable 50 Hz low-cut filter, an EQ bypass switch, and four-segment LED output metering. Professional XLR and 1/4-inch TRS connections make it easy to integrate into compatible mixers, signal processors, and amplifier systems.

With a frequency response extending below 10 Hz to above 50 kHz, a typical dynamic range greater than 112 dB, and low distortion, the dbx 131s delivers accurate analog equalization in a compact 1RU rackmount design.

Features & Benefits

Precise 31-Band Frequency Control

The dbx 131s provides 31 individual frequency bands using 1/3-octave Constant Q filtering. This allows technicians to make targeted frequency adjustments for loudspeaker tuning, room acoustics, and overall tonal balance.

Switchable ±6 dB and ±12 dB EQ Ranges

Choose the ±6 dB range for finer adjustments or the ±12 dB range when greater boost or cut is required. This makes the equalizer suitable for both detailed system tuning and general sound reinforcement.

Adjustable Input Gain and LED Metering

A ±12 dB input gain control provides flexibility when matching professional line-level signals. The four-segment LED output meter offers convenient visual feedback for monitoring signal levels.

50 Hz Low-Cut Filter

The switchable 50 Hz high-pass filter provides 12 dB-per-octave attenuation to help reduce unwanted low-frequency rumble and excessive bass energy when appropriate for the connected system.

Professional Balanced Audio Connections

Balanced XLR and 1/4-inch TRS inputs and outputs support integration with compatible professional audio equipment. RF-filtered connections help reduce susceptibility to unwanted interference.

Convenient EQ Bypass

The front-panel bypass switch removes the graphic equalizer section from the signal path, allowing users to compare processed and unprocessed audio during setup.

Compact Rackmount Construction

The dbx 131s occupies just 1RU of rack space. Its 6-inch depth and 4.8-pound weight make it practical for permanent installations and portable equipment racks.

Key Features

• Single-channel, 31-band graphic equalizer
• 1/3-octave Constant Q filtering
• Switchable ±6 dB or ±12 dB boost/cut
• ±12 dB input gain adjustment
• 20mm nonconductive EQ sliders
• Switchable 50 Hz low-cut filter
• Front-panel EQ bypass switch
• Four-segment LED output meter
• Balanced XLR and 1/4-inch TRS connections
• Frequency response below 10 Hz to above 50 kHz
• Typical dynamic range greater than 112 dB
• Compact 1RU rackmount design

Ideal Applications

The dbx 131s is suitable for professional audio applications requiring dedicated single-channel equalization, including live PA systems, houses of worship, school auditoriums, recording studios, touring equipment racks, theaters, and commercial audio installations.

dbx 131s Technical Specifications

Specification	Details
Manufacturer	dbx Professional
Model	131s
Product Number	DBX131SV
Product Type	Single-Channel Graphic Equalizer
Channels	1
EQ Bands	31
Filter Type	1/3-octave Constant Q
Boost/Cut Range	±6 dB or ±12 dB
Input Gain	±12 dB
Input Connectors	1/4" TRS, female XLR (pin 2 hot)
Input Type	Electronically balanced/unbalanced, RF filtered
Input Impedance	40kΩ balanced, 20kΩ unbalanced
Maximum Input	Greater than +21 dBu
CMRR	Greater than 40 dB, typically greater than 55 dB at 1 kHz
Output Connectors	1/4" TRS, male XLR (pin 2 hot)
Output Type	Impedance-balanced/unbalanced, RF filtered
Output Impedance	100Ω balanced, 50Ω unbalanced
Maximum Output	Greater than +21 dBu into 2kΩ or greater; greater than +18 dBm into 600Ω
Bandwidth	20 Hz–20 kHz, +0.5/−1 dB
Frequency Response	Below 10 Hz to above 50 kHz, +0.5/−3 dB
Dynamic Range	Typically greater than 112 dB
Signal-to-Noise Ratio	Typically greater than 95 dB
THD + Noise	Less than 0.003%
Low-Cut Filter	50 Hz, 12 dB/octave
Power Supply	100–240 VAC, 50/60 Hz
Power Consumption	15W
Power Connection	IEC receptacle
Rack Height	1RU
Dimensions	19"W × 1.75"H × 6"D
Net Weight	4.8 lbs (2.2 kg)
Shipping Weight	6.2 lbs (2.8 kg)

Installation and Compatibility

The dbx 131s is designed for professional line-level audio systems and can be connected between compatible mixers, processors, and power amplifiers.

Because this is a single-channel equalizer, stereo applications requiring independent left and right equalization need two units or a compatible dual-channel equalizer.

For best results, adjust input gain and equalization settings to maintain proper signal levels and avoid unnecessary clipping.

Why Buy the dbx 131s from Audio Supply?

Audio Supply offers professional audio processing equipment for live sound, recording, and installed applications. The dbx 131s provides precise analog equalization, straightforward operation, and professional connectivity for dependable sound system adjustments.