line, are designed for security, surveil- lance, and conference-table use. Since they do not look like microphones, they are incon- spicuous. Each mic’s tubular housing mounts in a 25/32-inch diameter hole in a ceiling panel, wall or table.
The PZM-10 has a mic-level output and a 3-pin XLR-type connector for easy plug-in installation. The mic requires 12 to 48V phantom power.
The PZM-10LL has a line-level output from its unterminated cable. It requires 12 to 24V DC.
Features:
•Pressure Zone Microphones for security and surveillance
•Clear, intelligible pickup of speech
•Choice of mic level output (PZM-10) or line-level output (PZM-10LL)
•Inconspicous, resembles a light switch
•PZM-10 powered by 12-48V phantom power
•PZM-10LL powered by 12-24V DC
Like other Pressure Zone Microphones, the PZM-10 and PZM-10LL use a miniature mic capsule mounted very near a sound-reflect- ing 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.
Frequencies below the voice range are rolled off to reduce pickup of air conditioning rum- ble. The high-frequency response is boosted slightly to help articulation. Because of their tailored response and PZM construction, the PZM-10 and PZM-10LL will pick up conver- sations or other desired sounds with extra clarity and definition.
The output is balanced, low impedance, which allows long cable runs without hum pickup or high-frequency loss.
The mic’s humbucking transformer and steel case prevent hum pickup, even near fluores- cent lights.
Mic Placement
To pick up speech from a small conference table (about 6 feet square), mount the PZM- 10 or PZM-10LL in the middle of the table. For longer tables, use one PZM in the middle of every 4 to 6 people. No person should be more than 3 feet from the nearest micro- phone.
(continued on back)
Specifications
Transducer type: Electret condenser.
Frequency response (typical):
PZM-10: 80 Hz to 20,000 Hz. See Fig. 1. PZM-
10LL: 100 Hz to 20,000 Hz. See Fig. 2.
Polar pattern: Hemispherical.
Impedance:
PZM-10: 240 ohms, balanced.
PZM-10LL: 75 ohms, balanced. Recommended minimum load impedance 1000 ohms.
Open circuit sensitivity:
PZM-10: 2.5 mV/Pa* (–52 dBV/Pa).
PZM-10LL: 1.4V/Pa* (+3 dBV/Pa).
See Table 1.
Power sensitivity:
PZM-10: –52 dBm/Pa*.
PZM-10LL: +8 dBm/Pa*.
Equivalent noise level (self-noise): 26 dB SPL typical (0 dB = .0002 dyne/cm2), A-weighted.
S/N Ratio: 68 dB at 94 dB SPL.
Maximum SPL: 120 dB SPL produces 3% THD.
Operating voltage:
PZM-10: 12 to 48V phantom power, positive voltage on pins 2 and 3 with respect to pin 1. PZM-10LL: 12 to 24V DC, positive voltage on red lead with respect to shield.
Polarity:
PZM-10: Positive pressure on the diaphragm produces a positive voltage on pin 2 with respect to pin 3 of output connector. PZM-10LL: Positive pressure on the diaphragm produces a positive voltage on white lead with respect to black lead.
Operating Temperature Range: –10° to +60° C
(+14° to +140° F).
Current drain:
PZM-10: 400 microamperes.
PZM-10LL: 2.8 mA at 12V DC, 4.22 mA at 24V DC. See Table 1.
Output connectors:
PZM-10: Male XLR type (3-pin pro audio). PZM-
10LL: None.
Cable:
PZM-10: None supplied. Use 2-conductor shielded mic cable.
PZM-10LL: 12-in., permanently attached 3-con-
ductor shielded cable. Red: B+, White: audio+,
Black: audio–, Shield: ground.
Materials: Steel plate and housing.
Finish: Off-white. May be painted any color; take care to first seal the opening between the capsule and boundary plate.
Net weight: PZM-10: 2.6 oz. (73.6 g).
PZM-10LL: 3.3 oz. (93.9 g).
Dimensions: See Fig. 3.
*1 pascal = 10 dynes/cm2 = 10 microbars = 94 dB SPL.
Table 1
Effect of power-supply voltage on
PZM-10LL sensitivity and current drain
B+ | SENSITIVITY | DRAIN |
24V | 1.4 V/Pa | 4.22 mA |
20V | 1.4 V/Pa | 3.00 mA |
15V | 1.0 V/Pa | 2.75 mA |
12V | 0.9 V/Pa | 2.50 mA |
