Electro-Voice RE20

A 737-gram steel cylinder that killed the proximity effect and became the default voice of American radio.

Overview

Pick one up and the weight hits you first: 737 grams, just over a pound and a half of steel-bodied dynamic microphone. It feels more like a machined tool than audio gear. Put your lips against the grille and it simply doesn't boom. That missing thump is the whole point of the RE20, and it's why the microphone turned up in broadcast booths and voiceover studios everywhere.

Electro-Voice built the RE20 as a professional-quality dynamic cardioid for recording, broadcast, and sound reinforcement. The spec sheet reads like a condenser's - a wide-range uniform frequency response from 45 Hz to 18,000 Hz, output of 1.5 mV/pascal, and a nominal impedance of 150 ohms balanced. None of that requires phantom power, and the microphone is essentially immune to the overload and distortion that phantom-powered condensers can suffer when a source gets loud. Owners report that this is why it survives kick drum duty and close-miked guitar cabs that would make a cheaper condenser flinch. The manual is blunt about it: the transient response makes it "easily comparable to the finest condenser cardioid microphones."

The bass-tilt switch is the other half of the story. With the filter off, the microphone is essentially flat from 80 Hz to 6,000 Hz, with a broad 2.5 dB rise between 6,000 and 14,000 Hz and a nominal 3 dB down at 18,000 Hz. Below 80 Hz it rolls off to nominally 3 dB down at 45 Hz. Flip the switch on and low-frequency response tilts down 4.5 dB from 400 to 100 Hz. That's the setting for when the mic sits across a desk from a host rather than two inches from a kick drum. Recording-Engineer (December 1983, p.100) pitched the RE20 at broadcast engineers wrestling with the lack of a consistent "studio sound," arguing that the simplest and often least expensive way to establish and maintain that consistency was to standardize on this one microphone. That's a magazine advertisement, not an independent measurement.

Key Features

Variable-D and the Vanishing Proximity Effect

Every directional microphone boosts bass as the source gets closer. That's the proximity effect, and most engineers learn to work around it with EQ or distance. The RE20 sidesteps it through Electro-Voice's Variable-D technology, a dual-ported, continuously variable system that controls the effect rather than compensating for it after the fact. The microphone can sit very close to a source without losing clarity or definition, which is why it works for tight vocals, inside bass drums, and on acoustic guitars. Singers can close-talk it with their lips almost touching the grille screen with no worry about plosives or excessive sibilance, because the integral blast and wind filter covers every acoustic opening. Part of that same filter assembly shock-mounts the internal element, cutting down the transfer of external vibration.

Acoustalloy Diaphragm and Low-Mass Voice Coil

The performance comes from a large Acoustalloy diaphragm paired with an exceptionally low-mass aluminum voice coil. That combination lets a moving-coil dynamic reproduce extremely high sound pressure levels without the overload and distortion you'd expect from a condenser. It also keeps the RE20 working in high humidity and elevated temperatures that would seriously degrade a competitive condenser - no phantom power, no polarized element. The diaphragm sits behind a shield that keeps dust and iron particles away from it, which helps in a studio that's been running for thirty years.

Steel Case and Hum-Bucking Coil

The housing is steel, finished in nonreflecting fawn beige, and a hum-bucking coil handles magnetically induced noise. The manual claims typical hum pickup of -130 dBm at 60 Hz in a one-millioersted field. The body measures 8.53 inches long, with a widest diameter of 2.14 inches and a body diameter of 1.94 inches. A stand clamp is included. The optional 309A shock-mounted stand adapter exists for floor stands and recording booms. Studio-Sound (January 1978, p.66) described the mechanical nesting concept behind the design - internal transducer parts nested one within another - as what allows the RE20 to withstand the rigors of professional use.

Cardioid Pattern, Effectively a Cardioid of Revolution

Off-axis response is where a lot of cardioids fall apart, and it's where the RE20 holds together. The pattern is described as sufficiently uniform in all planes to be effectively a cardioid of revolution. Response at any angle away from the major axis stays similar in shape to the on-axis response, just attenuated uniformly across the band. Rejection exceeds 15 dB at 180 degrees from 45 Hz to 10,000 Hz, and above 10,000 Hz it still exceeds 13 dB. That keeps the room out of the recording, with no off-axis coloration and a cleaner null directly behind the microphone.

Historical Context

The company's 2010 documentation carries a Bosch Communications Systems copyright, reflecting the brand's later ownership; the microphone itself long predates that. It has been a fixture in voice booths and broadcasting studios, and the manual's feature list names it a favorite of broadcast show hosts and voiceover studios — a reputation that outlasted every format change radio threw at it.

Collectibility & Value

The RE20 never really became a collector's item, because it never stopped being a working tool. Used examples turn up regularly. The design is famously hard to kill: steel body, nested internals, no phantom power to fry.