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.
Page 2
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.
Page 3
20.7" [525mm]
18.5" [470mm]
6.9" [175mm]
Engineering Data Sheet
Technical Specifications:
Generation Element: Dual condenser, back electret
Frequency Response: 50 Hz - 20,000 Hz (see chart)
Polar Patterns (see chart): Omnidirectional
Switches and Controls: Top mounted momentary push-button
shielded) black cable, terminated
with a professional 3-pin male XLR
style connector with gold plated pins
and LED control
5 Volts = Logic High
0 Volts = Logic Low
Base Width = 117 mm (4.6 in.)
Base Height = 56 mm (2.2 in.)
Gooseneck Length =
470 mm (18.5 in.)
Max Head Diameter =
14.6 mm (0.58 in.)
Gooseneck Diameter, Upper =
6.4 mm (0.25 in.)
Gooseneck Diameter, Lower =
7.9 mm (0.31 in.)
Color: Nonreflecting Black
-29° to 74°C (-20° to 165°F)
Relative Humidity, 0-95%:
-29° to 57°C (-20° to 135°F)
EV Multi-Port Windscreen:
The PC Desktop microphone comes with the exclusive EV
Multi-Port Windscreen. This unique one-piece ported design
offers greatly improved resistance to “P”-popping noise by
creating a two-stage filter that has an air space between the
stages. This makes the multi-port windscreen as effective as
much larger traditional designs.
Dimension Drawings:
Page 4
Frequency Response:
Polar Response:
Architectural & Engineering Specs:
The microphone shall be a freestanding, tabletop microphone. The base will have a 10-foot integral 5-conductor (2-conductor
shielded) cable terminated in a 3-pin XLRM connector. The microphone shall have four selectable polar patterns: omnidirectional, cardioid, supercardioid, and hypercardioid. The mic will use a pair of back-electret condenser elements with a frequency
response of 50 Hz to 20 kHz. The microphone shall have a nominal, balanced output impedance of 200 ohms. The microphone
will have a switchable high-pass filter to roll off low frequencies. The microphone shall have an output level of 5.6 mV/Pascal
and outputs shall not be appreciably affected by the following temperature and humidity extremes: -29° to 74° C (-20° to 165°F)
when the relative humidity is 0-50%; -29° to 57°C (-20° to 135°F) when the relative humidity is 0-95%. Dimensions shall be 526
mm (20.7 in.) long with a maximum head diameter of 14.6 mm (0.58 in). The PC Desktop-18RD microphone shall include a 470
mm (18.5 in.) gooseneck. The gooseneck will be attached to a base that has a top mounted push-button and a status LED that
lights when audio is active. The push-button will be configurable to operate in either momentary or toggle mode. When the
microphone is set in momentary mode, the push-button can be programmed to operate in either push-to-mute or push-to-talk
mode. When the microphone is set in toggle mode and power is initially applied, the status of the microphone can be programmed to be either on or muted. The microphone will be capable of operation with automatic mixers by means of a configuration switch located on the bottom of the microphone. When the microphone is in automatic mixer mode, normal LED and
top push button functions are disabled. In automatic mixer mode, audio will always be on, the top push button will only change
the logic level on the microphone’s white wire, and a logic low level on the microphone’s orange wire will cause the LED to illuminate. All controls except for the push button shall be accessible from the bottom of the microphone base. The microphone
base shall be of metal construction. The microphone will include an external windscreen. The microphone shall have a nonreflecting black finish. The Electro-Voice PC Desktop-18RD is specified.