Equalisers

Equalisers, or EQs, are tools used in recording studios to adjust the frequency response of an audio signal. Classic EQ units are typically used to cut or boost certain frequencies, allowing the engineer to shape the overall sound of a recording. The frequency bands that an EQ can adjust can vary, but most common EQs feature a low-frequency band, a mid-frequency band, and a high-frequency band. The engineer can adjust the gain of each band to either cut or boost specific frequency ranges in the audio signal.

Related Articles: Equalising for Spectral Character | The Birth of the Parametric Equaliser

Made In U.S.A.
Released in 1951 /
First introduced in 1951, the Pultec EQP-1 Program Equaliser was the first passive equaliser on the market. Upon its introduction, it changed the recording world forever, offering a new way to manipulate sound. The fact that Pultec equalisers in one form or another are still in use today, is extraordinary.
Made In U.K.
Released in 1951 /
The EMI RS56, or UTC (Universal Tone Control), was a semi-parametric equaliser developed by EMI in 1951 for disc cutting. It gained legendary status at Abbey Road, especially during Beatles sessions, thanks to its flexible three-band EQ and stepped controls. Nicknamed the “Curve Bender,” it was eventually replaced by the TG12412 in the 1970s but remains one of EMI’s most iconic designs.
Made In U.S.A.
Released in 1955 /
The Pultec MEQ-5 provides fine control over the “power region” (300 Hz to 5000 Hz), where most audio energy is focused and the ear is highly sensitive. Smooth handling of this range is crucial, as minor acoustic or equipment resonances can greatly affect sound clarity and listenability.
Made In U.S.A.
Released in 1956 /
The Langevin EQ-258-A Program Equalizer is a rare 1950s passive EQ, offering selectable frequencies at 40Hz, 100Hz, 3kHz, 5kHz, 10kHz, and 15kHz, with up to +12dB boost and -16dB cut. Known for its smooth, musical tone and rugged build, it remains a prized tool for adding vintage character and tonal balance to recordings.
Made In U.S.A.
Released in 1956 /
The UTC 4-B EQ Filter was introduced in the 1950s, crafted by the United Transformer Corporation (UTC), and renowned for its warm and natural sound, achieved through a transformer-coupled design that shapes audio signals without active electronics.
Made In U.S.A.
Released in 1958 /
The Blonder-Tongue Audio Baton, introduced in 1959, is an equaliser featuring nine octave-band controls, each capable of boosting or attenuating specific frequency ranges by up to ±14 dB. Designed for high-fidelity systems and public address applications, it offered users the ability to finely adjust frequency balance to correct system deficiencies, enhance tonal characteristics, and improve speech intelligibility.
Made In Germany
Released in 1961 /
The Klein + Hummel UE-100 is a modular, valve-based studio equaliser that uses RC networks rather than inductors to deliver extremely accurate, low-noise and repeatable tone-shaping with symmetrical I/O, stepped controls and pushbutton-selected filter networks, suitable from microphone lines to mastering tasks.
Made In U.S.A.
Released in 1961 /
The Pultec EQP-1A is a classic equaliser known for its warm, smooth sound, achieved through a unique design that allows simultaneous frequency boosting and cutting. Introduced in 1961, its tube-driven, passive circuitry adds depth and clarity, making it a favourite for enhancing bass and airy highs. Its “Pultec sound” remains a staple in studios for its natural, musical character.
Made In U.S.A.
Released in 1962 /
The Lang PEQ-2 Program Equaliser, released in the mid-20th century, was a groundbreaking tool for audio professionals, offering precise tonal shaping and reliability. Featuring non-drift components, high-Q toroidal coils, and a hermetically sealed design, it delivered low noise, low power consumption, and unmatched durability.
Made In U.S.A.
Released in 1963 /
The Altec 9063A is a vintage passive equaliser from the 1960s, offering precise tonal shaping with boost and attenuation options. Known for its simplicity and robust design, it remains highly sought after in the second-hand market for mixing and mastering applications.
Made In U.S.A.
Released in 1970 /
The Urei 565 Filter Set introduces to the recording studio and motion picture sound department an effective tool for ‘saving’ problem tracks, and for creating innovative special effects.
Made In Germany
Released in 1971 /
Klein & Hummel’s UE 1000 is a discrete, programme equaliser from the 1970s aimed at mastering and programme work, valued for its musical networked filters and solid professional construction.