Electro-Voice 18RD User Manual

Key Features:

Multi-pattern versatility. Choose between •
omni, cardioid, supercardioid or hypercardioid
to easily adapt to any situation.

Consistent microphone voicing across all four •
patterns.

Switch can be programmed to operate as •
either latching on/off or momentary push-to­mute/push-to-talk.

Disassembly of the mic isn’t required to •
change switch functions.

Compatible with echo cancellation for confer-•
ence applications.

High visibility blue LED clearly displays mic •
status to user.

Exceptional sound quality with EV’s proven •
PolarChoice design.

PolarChoice Series

PC Desktop-18RD

Multi-Pattern Desk Microphone

with Automatic Mixer Logic

General Description:

The PC Desktop-18RD is a high quality desk microphone that can be used with both standard and automatic mixers.

The PC Desktop-18RD features the exclusive EV PolarChoice miniature multi-pattern gooseneck microphone. The multi­pattern versatility of the PolarChoice microphone makes it a true “problem solver”. With one non-directional and 3 directional
polar patterns available, the PolarChoice microphone is ideal for virtually any installation. The PC Desktop-18RD also includes
a switchable high pass filter that helps reduce any vibration induced noise pickup.

The PC Desktop-18RD features a large push button mute switch that has a much better “feel” than membrane switches. The
mute button can be configured for push-on / push-off, push-to-talk, or push-to-mute function. Switch programming is easily
accomplished without disassembling the microphone. A switch on the bottom quickly converts the PC Desktop-18RD to auto­matic mixer mode. In this mode, audio is always on.

Applications:

The PC Desktop-18RD is acoustically designed for high-quality sound reinforcement and broadcast applications. The frequency
response is tailored for wide-range sound reproduction with very natural sound pick-up for either distant or close-up use. The
PC Desktop-18RD can be used on lecterns, podiums, desks, table-tops, or other applications. To maximize gain-before-feed­back, the PolarChoice’s three directional polar patterns allow the user to pick the directional polar pattern for optimum effect.
For those applications where gain-before-feedback is not a problem, an omnidirectional pattern is included. Applications
requiring speaking close to the microphone at podiums, lecterns, or pulpits normally require a windscreen (included) to control
breath noise and P-popping or, in some cases, wind noise from circulating air.

PC Desktop-18RD Microphone

Microphone Setup:

Cardioid

Supercardioid

Hypercardioid

Omnidirectional

Figure 1: PC Desktop Controls

Refer to Figure 1 for the following switch function descriptions-

Switch “A” - Select High-Pass switch position. Start with this

switch set to the left (flat response). If the mic is in a
location where low frequency rumble or wind noise is a
encountered, moving this switch to the right will help by
reducing low frequency sensitivity.

Flat ( ): Normal response.
High Pass ( ): minimum 5 dB reduction
in sensitivity at 100 Hz.

Switch “B” - Select preferred polar pattern. The cardioid

polar pattern works well for most installations. If feed­back from a sound system occurs, switching to the
supercardioid or hypercardioid pattern will usually allow
increased mic gain before feedback. The omnidirec­tional pattern is best suited for situations where there
is no sound reinforcement system present, such as for
recording.

Switch “C” and “D” - Controls action of push-button switch

on the top of the PC Desktop microphone.

Momentary modes - When switch “C” is set to the left,

the push-button (mute) switch action is momentary.

Figure 2:

Bottom View

Figure 3: PC Board Detail

Switch “E” (Logic Mode Select) - When switch “E” is set

in the left hand position, the PC Desktop operates as a
normal desk microphone. Mic muting and operation of
the LED is controlled by the push-button on the top of
the mic.
With switch “E” in the right hand position, the mic will be
in automatic mixer mode, and the following will apply:

1) Mic audio is always on.

2) The automatic mixer controls LED operation and mic
muting.

Wiring - For non-automatic mixer applications, the PC

Desktop comes equipped with a standard XLR style
3-pin male connector. For automatic mixer applications,
remove the XLR connector and service the cable as
needed.

Cable Connections -

Red – Balanced Audio High
Black – Balanced Audio Low
Shield – Audio Ground
Green – Logic Ground (Common to shield unless R45 is
removed. See Figure 3.)
White – Switch Logic
Orange – LED Control

In addition, If switch “D” is in the left hand position,

the mic will be in push-to-mute mode.

Alternately, If switch “D” is in the right hand position,

the mic will be in push-to-talk mode.

Toggle Modes - When switch “C” is in the right hand

position, the push-button (mute) switch will be in
toggle (push-on/push-off) mode.

With switch “C” in the right hand position, the setting

of switch “D” determines if the mic audio should be
muted when power is first applied.

If switch “D” is in the left hand position, the mic

audio will be muted when power is first applied.

If switch “D” is in the right hand position, mic audio

will be on when power is first applied.)

Logic Signals - If the PC desktop mic is in momentary mode

(see above section on the mute switch), the logic level
on the white wire will normally be “high”, and go “low”
when the push-button is pressed. If the mute switch is
set for toggle mode, the logic will toggle from high to
low, or from low to high, each time the button is pressed.
(If desired, a pc board change can be done to force the
logic to always be momentary, regardless of switch set­tings. See Figure 3).

LED Control - When the mic is in automatic mixer mode,

a low logic signal on the orange LED control wire will
cause the LED to light.

Logic Ground Lift - If necessary, the logic and audio grounds

can be separated. This requires removing a resistor from
the pc board. See Figure 3.