Single Channel Mastering Quality Equalizer with Simple and Intuitive Interface



  • Low Cut Filter: 50 Hz to 5 kHz in two ranges, continuously adjustable
  • See-Saw Filter: simultaneous bass boost / treble cut and vise versa
  • See-Saw pivot frequency switchable from 120 Hz to 26 kHz in two ranges
  • 8 dB max See-Saw cut / boost
  • High Cut Filter: 3 kHz to >200 kHz continuously adjustable
  • Low and high cut filters use gentle and musical -6 dB / octave
  • Balanced input and output
  • Unity gain, with output driving either balanced or unbalanced
  • Input impedance: 48k Ohms differential
  • Output impedance: 100 Ohms differential
  • Max input level: +20 dBu
  • THD: 0.002 % Typ at +20 dBu
  • CMRR: 90 dB Typ at 60 Hz
  • Noise: -96 dBu

The Ingram Engineering EQ52 is a 500-series equalizer module that contains extremely versatile and musical sounding low cut, high cut, and see-saw filters. The unique see-saw filter contains a combined low and high frequency control that allows broad frequency response adjustments with a single control knob. These key filter functions are provided with a simple and intuitive user interface.

The unit features differential input and output. Both input and output can operate in differential or single-ended, unbalanced modes. A high current, cross-coupled active output buffer mimics the behavior of a transformer, providing constant gain for balanced or unbalanced operation, when either the positive or negative output signals are grounded. Therefore, the output can drive differential or single ended output with no extra user configuration needed.

The simple controls and circuit layout belie the finely tuned and expertly engineered design. Extremely high input common mode rejection capability is realized, even down to critical power supply frequencies. High qualify film caps, low distortion resistors and excellent quality integrated active stages realize a high headroom, low noise, and low distortion equalizer with superb audio quality that is ideal for individual tracks or for mixing and mastering stereo signals when the modules are used in pairs.

Product Literature

Audio Sample Files with Various EQ Settings

The following files show the capabilities of this equalizer. Various music was recorded then equalized to show the effects of the Low Cut, High Cut, and See-Saw filters.

The following audio samples were recorded by Michael Frasinelli of Audio Producer News. The samples include isolated bass, vocals, and a master mix. Michael did a great job showing how the equalizer can be used to fine tune the music to bring out its best character. For comparison, samples with no EQ are included, as well as some samples that use EQ plugins. The plugins provide a very good contrast to the Ingram Engineering equalizer's silky result.

For offline, high resolution A/B comparisons, .WAV files can be downloaded, then loaded into your DAW.


Bass Samples

-3.25dB@1KHz 25Hz HPF, 15KHz LPF
-3.25dB@400Hz 30Hz HPF
Plugin -3.25dB@400Hz

Master Samples

1KHz -.75dB 20Hz HPF Final Setting
400Hz -.75dB 20Hz HPF
Plugin Matched to 1KHz Setting

Slap Bass Samples

+1.5dB@400Hz 22Hz HPF, 10KHz LPF
-3dB@1KHz 22Hz HPF, 14KHz LPF
Plugin -4dB@400Hz

Vocals Samples

-.75dB @ 1KHz 125Hz HPF 17KHz LPF
-1dB @ 1KHz 125Hz HPF
Plugin -1dB @ 1KHz Added Clean 125Hz Plugin HPF