AtlasIED EQM131 31-Band 1/3-Octave Graphic Equalizer

The AtlasIED EQM131 is a professional 31-band, 1/3-octave graphic equalizer designed for precise frequency adjustment in commercial audio, paging, background music, and sound masking systems. Featuring ISO-centered constant-Q filters, selectable ±6dB or ±12dB equalization ranges, and versatile balanced and unbalanced connections, the EQM131 provides dependable audio system tuning in a compact 1RU rackmount design.

With 31 individual frequency bands, the EQM131 allows installers and audio technicians to adjust specific portions of the audio spectrum to compensate for room acoustics, improve speech intelligibility, or tailor system response to the intended application.

Its constant-Q filter design helps minimize interaction between adjacent frequency bands, allowing more predictable adjustments when creating equalization curves.

The EQM131 includes balanced XLR and 1/4-inch TRS connections for professional audio equipment, along with unbalanced RCA connections for compatible consumer-level audio sources.

Front-panel high-pass and low-pass filters, gain control, and selectable equalization ranges provide additional flexibility for commercial sound installations.

Whether you're tuning a school paging system, adjusting background music in a retail environment, or shaping the frequency spectrum of a sound masking system, the AtlasIED EQM131 offers practical control over system frequency response.

31-Band Precision Graphic Equalization

The AtlasIED EQM131 provides 31 individual equalization bands arranged at 1/3-octave intervals.

This design allows technicians to make detailed frequency adjustments across the audio spectrum.

Unlike basic tone controls that adjust broad frequency ranges, a 31-band graphic equalizer provides more precise control over individual portions of the signal.

This can be particularly useful when addressing:

• Excessive low-frequency buildup
• Midrange coloration
• Speech intelligibility issues
• Uneven system frequency response
• Room-related acoustic problems
• Sound masking spectrum adjustments

The EQM131's individual frequency controls make it easier to develop a repeatable equalization curve for a particular installation.

ISO-Centered Constant-Q Filters

The EQM131 incorporates ISO-centered constant-Q filters designed to provide predictable equalization performance.

Constant-Q filtering helps maintain more consistent filter bandwidth as boost or cut adjustments are made.

This reduces unwanted interaction between neighboring frequency bands and allows installers to make more precise adjustments.

For commercial audio systems, this is especially useful when shaping a response curve to suit room acoustics or specific loudspeaker characteristics.

The result is greater control over frequency balance without relying on broad adjustments that may affect more of the audio spectrum than intended.

Selectable ±6dB or ±12dB Equalization Range

The AtlasIED EQM131 offers two selectable equalization ranges:

• ±6dB for finer frequency adjustments
• ±12dB for more extensive correction

The ±6dB setting is useful when making smaller changes to system response.

The ±12dB setting provides additional adjustment range when more substantial frequency shaping is required.

This flexibility allows the EQM131 to serve different commercial audio applications without requiring separate equalizers for different adjustment needs.

For best results, excessive frequency boosting should be avoided when possible to preserve system headroom.

High-Pass and Low-Pass Filtering

The EQM131 includes front-panel high-pass filter (HPF) and low-pass filter (LPF) controls.

These filters provide additional frequency management beyond the individual graphic EQ bands.

The high-pass filter can help reduce unwanted low-frequency content, while the low-pass filter can limit higher-frequency material when required by the application.

These functions are useful for:

• Commercial paging systems
• Background music installations
• Sound masking systems
• General-purpose audio equalization

The combination of graphic equalization and filtering gives installers additional control over the frequency range delivered to downstream equipment.

Balanced XLR and TRS Connections

The AtlasIED EQM131 provides balanced XLR and 1/4-inch TRS connections for integration with professional audio equipment.

Balanced connections are commonly used in commercial audio installations because they help reduce susceptibility to interference over properly installed cable runs.

The EQM131 can be incorporated into systems using compatible:

• Commercial audio mixers
• Paging equipment
• Professional signal processors
• Power amplifiers
• Audio distribution equipment

These connections make the EQM131 suitable for a variety of installed sound applications.

Unbalanced RCA Connectivity

In addition to its balanced connections, the EQM131 includes unbalanced RCA inputs and outputs.

These connections allow integration with compatible consumer-level audio equipment.

This can be useful when an installation combines professional commercial audio components with equipment operating at nominal -10dBV signal levels.

The availability of both balanced and unbalanced connections provides flexibility when integrating the equalizer into existing systems.

Sound Masking System Equalization

One of the specialized applications for the AtlasIED EQM131 is sound masking system tuning.

Sound masking systems introduce a controlled background sound spectrum to help reduce the intelligibility of distracting conversations in certain environments.

The EQM131's 31-band equalization provides detailed control over the frequency balance of a masking signal.

When used with compatible equipment such as the AtlasIED AA120M mixer amplifier and AA-SMG sound masking module, the EQM131 can help shape the masking spectrum for the installation.

Proper sound masking performance depends on system design, speaker placement, acoustic conditions, and appropriate calibration.

The EQM131 provides frequency adjustment capability as part of that larger system.

Improve Paging and Background Music Performance

The EQM131 is also useful for general commercial paging and background music applications.

In paging systems, frequency adjustment can help emphasize the speech frequencies most important for intelligibility.

For background music systems, equalization can help compensate for room acoustics or adjust tonal balance to suit the environment.

Typical applications include:

• School paging systems
• Office background music
• Retail audio installations
• Commercial public address systems
• Institutional sound systems
• Multi-room audio distribution
• General installed sound reinforcement

The EQM131 allows installers to tailor system response rather than relying entirely on the characteristics of the source equipment and loudspeakers.

Low-Noise Design and Wide Dynamic Range

The AtlasIED EQM131 is designed for professional audio signal processing.

Its low-noise design and wide dynamic range support audio equalization in commercial sound systems.

The manufacturer-listed maximum output levels are:

• +22dBu balanced
• +18dBu unbalanced

These output specifications support integration with compatible professional and unbalanced audio equipment.

Appropriate system gain structure should be maintained to avoid unwanted noise or signal overload.

Durable 1RU Rackmount Construction

The EQM131 features an all-metal chassis designed for professional equipment rack installations.

Its 1RU design allows it to occupy minimal rack space while providing access to 31 individual frequency controls.

The unit's manufacturer-listed width is 19 1/16 inches.

Its rackmount design makes it suitable for commercial AV equipment rooms, paging system racks, and other permanent audio installations.

Ideal Applications for the AtlasIED EQM131

The EQM131 is suitable for a variety of commercial audio applications requiring precise frequency adjustment.

Common uses include:

• Sound masking system equalization
• Commercial paging systems
• Background music installations
• School and institutional audio
• Office sound systems
• Retail audio systems
• Public address systems
• Commercial sound reinforcement
• Professional audio signal processing
• Room response correction

Its combination of 31-band equalization, constant-Q filters, and versatile connectivity makes it a practical choice for commercial audio system tuning.

AtlasIED EQM131 Key Features

• Professional 31-band graphic equalizer
• 1/3-octave frequency band spacing
• ISO-centered constant-Q filters
• Selectable ±6dB or ±12dB boost/cut range
• Front-panel high-pass filter
• Front-panel low-pass filter
• Front-panel gain control
• Balanced XLR inputs and outputs
• Balanced 1/4-inch TRS inputs and outputs
• Unbalanced RCA inputs and outputs
• Compatible with professional and consumer-level audio equipment
• 20Hz–20kHz frequency response
• Maximum balanced output level of +22dBu
• Maximum unbalanced output level of +18dBu
• Low-noise design
• Wide dynamic range
• Durable all-metal chassis
• Compact 1RU rackmount design
• Suitable for sound masking, paging, and background music
• 36-month manufacturer warranty

AtlasIED EQM131 Technical Specifications

Why Buy the AtlasIED EQM131 from Audio Supply?

At Audio Supply, we specialize in professional audio equipment for commercial paging, sound masking, background music, and installed sound systems.

The AtlasIED EQM131 provides precise 31-band equalization, versatile connectivity, and straightforward front-panel controls, making it a practical solution for commercial audio applications requiring accurate frequency adjustment.

Whether you're tuning an existing paging system or designing a new sound masking installation, Audio Supply can help you select the right professional audio equipment for your project.