The Electro-Voice Model RE18 supercardioid dynamic microphone
Description and Applications The Electro-Voice RE18 is a shock-isolated Variable-D dynamic supercardioid microphone created for the most exacting professional use. The transmission of hand, stand and mechanically generated lectern noises is sharply reduced making the RE18 ideally suited for broadcasting and high-quality sound reinforcement.
The RE18 is much like the RE16, except that it employs a unique internal shock mount and a refined, low profile blast filter. All of these features are provided in a small package with functional, easy to hold styling. The fawn-beige finish is ideal for on-camera use. The RE18 is also at home in the recording studio and in the field with news and sports broadcasters.
Figure 1 — Frequency response
The dynamic element and the complex acoustic ports of the Variable-D RE18 are completely shock-isolated from the steel outer case. The unique isolation system utilizes butyl-rubber doughnuts and viscous damping fluid to provide a degree of shock isolation unknown in a microphone housed in such a small outer case (¾-inch diameter). The butyl rubber not only acts as a spring in the isolation system, but also serves as a mechanical damper, which converts shock energy to heat.
The integral blast filter, smaller than that of the RE16, but of equal effectiveness, provides excellent control of vocal p-pops.
Design refinements include three-stage construction and the use of both standard and high-density Acoustifoam. The RE18 has a Memraflex grille that bounces back to retain its shape.
Figure 2 — Dimensions
The RE18’s Variable-D design essentially eliminates proximity effect. All Single-D microphones exhibit bass-boosting proximity effect when the microphone is used within a working distance of about 12 inches. At a ¼-inch working distance, the RE18’s Variable-D design reduces proximity effect to less than 5 dB at 100 Hz, compared to the Single-D microphone’s typical 15 dB at 100 Hz. The result is a consistent sound quality regardless of working distance and a high degree of clarity when used up close.
The RE18’s supercardioid polar response provides two nulls at about 150 degrees off axis (see Figure 1). Typical cardioids have a single null at 180 degrees off axis. The supercardioid pattern provides greater rejection in the microphone’s rear hemisphere, advantageous on a boom and in many on-stage applications.
Figure 3 — Polar pattern
A hum-bucking coil has been added to the RE18 (see Figure 4), which, in addition to its screw-machined steel outer case, ensures rejection of hum when subjected to heavy alternating magnetic fields from stage lighting, transformers and other conditions that can occur in remote operation.
The hum-bucking coil in the RE18 gives an additional 25 dB of hum rejection. Hum pickup level is −125 dBm in a .001 gauss field.
Figure 4 — Wiring diagram
The exclusive nonmetallic Electro-Voice Acoustalloy diaphragm is virtually unaffected by extreme atmospheric conditions.
A carefully designed steel outer case provides a high degree of mechanical protection and the Memraflex grille screen resists denting.
Frequency Response: 80-15,000 Hz
Polar Pattern: Supercardioid
Impedance, Low-Z (nominal): 150 ohms
Output Level (0 dB = 1 mW/10 dynes/cm²): −57 dB
Hum Pickup Level (.001 gauss field): −125 dBm
Diaphragm: Electro-Voice Acoustalloy®
Case Material: Steel
Dimensions: Length: 178 mm (7.0 in.) Max. Diameter: 41 mm (1.63 in.) Shank Diameter: 19 mm (0.75 in.)