@crown
®
PRESSURE
ZONE
MICROPHONE
®
T
he PZM
®
-11LL is a Pressure Zone
Microphone
®
designed for security and
surveillance applications. It is designed to
look like a light switch, not a microphone, so
as not to draw attention.
The PZM-11LL looks and sounds like the
PZM-11, but has a line-level output and is pow-
ered by 24V AC, 12-24V DC, or phantom power.
Since the PZM-11LL has a high output, it can be
plugged directly into a VCR line input—no costly
mic preamp is needed.
The mic can be mounted in the ceiling or wall in
a standard electrical outlet box. It also can be
installed without a box because its electronics
are shielded inside a removable metal housing.
Like other Pressure Zone Microphones, the
PZM-11LL uses a miniature mic capsule
mounted very near a sound-reflecting plate or
boundary, in the Pressure Zone. In this zone,
direct sound from the sound source combines in
phase at all frequencies with reflected sound off
the boundary. The benefits are many: 6 dB more
sensitivity, 6 dB less noise, a wide smooth
frequency response free of phase interference,
excellent clarity and “reach,” and consistent
pickup anywhere around the mic.
In the PZM-11LL, low frequencies below the
voice range are rolled off to reduce rumble from
trucks, machinery, and air conditioning. The
high-frequency response is boosted slightly to
help articulation. Because of its tailored response
and PZM construction, the PZM-11LL will pick
up conversations or other desired sounds with
extra clarity.
The microphone connector is a row of screw
terminals for easy installation. The output is
balanced, low impedance, which allows long
cable runs without hum pickup or high-fre-
quency loss. The mic can also be wired unbal-
anced.
Installation
1. Please refer to Fig. 3 and locate all the parts
shown. The electrical box and cables are not
included.
2. Run a 2-conductor shielded mic cable to the
ceiling or wall hole where you intend to install the
microphone. If you wish, install a standard
electrical outlet box in the hole.
3. The PZM-11LL can be powered in three ways:
24V AC, 12-24V DC, or 12-48V phantom power.
The mic is wired at the factory to be powered by
an external 24V AC source so that it is compat-
ible with video surveillance systems where 24V
AC is readily available.
To use the phantom power, you need a mixer
with phantom power or an external phantom-
PZM-11LL
Specifications
Transducer type: Electret condenser.
Frequency response (typical): 80 Hz to 20,000 Hz
(see Fig. 1).
Polar pattern: Hemispherical.
Impedance: 75 ohms, balanced. Recommended
minimum load impedance 1000 ohms.
Open-circuit sensitivity, typical: 1.4 V/Pa*
(+3 dB re 1V/Pa).
Power sensitivity, typical: +8 dBm/Pa*.
Equivalent noise level (self-noise): 26 dB SPL
typical (0 dB = .0002 dyne/cm
2
), A-weighted.
S/N Ratio: 68 dB at 94 dB SPL.
Maximum SPL: 100 dB SPL produces 3% THD at
maximum gain.
Operating voltage: 24V AC, 12-24V DC, or phantom
power.
Polarity: Positive pressure on diaphragm produces
positive voltage on mic screw terminal 2 with
respect to screw terminal 3.
Current drain: 4 milliamperes.
Output connector: Screw terminals labeled OUTPUT.
Cable: None supplied. Use 2-conductor shielded mic
cable and twisted-pair power cable.
Materials: Steel plate and high-impact plastic capsule
holder.
Finish: Off-white. May be painted any color; take
care to first seal the opening between the capsule
and boundary plate.
Net weight: 2.5 oz. (71 g).
Dimensions: See Fig. 2.
®
*1 pascal = 10 dynes/cm
2
= 10 microbars = 94 dB SPL.
–20
–25
–30
–35
20
100
1K
+15
+10
+5
dB 0
–5
–10
–15
10K
Fig. 1
Frequency in Hz
Frequency Response
Fig. 2
2.778
1.510
4.530
2.680
1.160
.356
MIC
CABLE
ELECTRICAL
BOX
NUTS
LONG
SCREWS
CHASSIS
FACEPLATE
SCREW
POWER
CABLE
Fig. 3
