The Curve Bender #GearThatMadeUs

The Curve Bender #GearThatMadeUs

14th April 2022

The RS-56 UTC Equaliser (Universal Tone Control) was designed in 1951 by one of EMI's most skilled technicians, Mike Batchelor. It received the nickname Curve Bender for its ability to shape a sound.


Stereo RS-56S


At a time when most equaliser devices were simple affairs, this was a complex and very flexible tool, generally used in the cutting rooms during mastering.

The RS56 controls the volume of different frequencies with great detail and is an early example of what we now know as parametric EQ.

The specification of the original mono version states, “one of nearly 14 million pre-determined frequency response curves can be selected at will”.


Engineer Ken Scott with original mono Curve Bender


This stereo version was introduced in the mid-1960s and contains an intricate system of gears that allow dual control of both stereo channels, with the capability to adjust each side independently.


In celebration of our 75th anniversary, the curve bender was reimagined by Chandler Limited in the form of the EMI TG12345 Curve Bender unit. An incredible tool for both mixing and mastering.

Founder Wade Goeke turned the nine selections of the vintage version into 51 EQ points plus a multiply switch that increases the cut/boost up to ±13.5dB (as well as sharpening the Q), filters and bell/shelf selections on the high and low bands.

Its next manifestation came in the form of the RS56 Passive EQ plugin made in collaboration with Waves Audio.

Watch legendary engineer Peter Cobbin and our head of audio products Mirek Stiles discuss below!

#GearThatMadeUs #CurveBender #AbbeyRoad90

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