The Crown® PZM®-11 or PZM-11LL is a Pressure Zone Microphone® designed for conference-room, security and surveillance applications. Each can be mounted in the ceiling or wall in a standard electrical outlet box.
Providing excellent intelligibility, the PZM-11 and PZM-11LL are designed to look like a light switch so as not to draw attention. The PZM-11 has a mic-level output and is powered by 12-48V phantom power. The PZM-11LL has a line-level output and can be powered by 24V AC, 12-24V DC, or 12-48V 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.
To phantom power the PZM-11LL, a modification must be made to the electronics module (see Installation Step 3 for details). A factory modified version for direct phantom power is available as the PZM-11LLS2.
Like other Pressure Zone Microphones, the PZM-11and PZM-11LL utilize the Pressure Recording Process™ in which a miniature condenser microphone capsule is mounted very close to a sound-refl ecting plate or boundary. The capsule is mounted in the “Pressure Zone” just above the boundary, a region where sound coming directly from the sound source combines in-phase with sound refl ected off the boundary.
The benefits are a wide, smooth frequency response free of phase interference, excellent clarity and “reach,” and consistent pickup anywhere around the microphone. In the PZM-11and PZM-11LL, low frequencies below the voice range are rolled off to reduce pickup of air-conditioning rumble. The high-frequency response is boosted slightly to aid clarity and articulation.
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-frequency loss. Features
• Ideal for security, surveillance and conferrence rooms
• Clear, articulate sound
• Low-impedance screw-terminal output
• PZM-11 is mic level; PZM-11LL is line level Specifications Type: Pressure Zone Microphone. Element: Electret condenser. Frequency response (typical): 80 Hz to 20,000 Hz. Polar pattern: Hemispherical. Impedance:
PZM-11: 225 ohms, balanced.
PZM-11LL: 75 ohms, balanced.
Recommended minimum load impedance 1000 ohms. Open circuit sensitivity:
PZM-11: 5 mV/Pa* (–46 dBV/Pa).
PZM-11LL: 1.4V/Pa* (+3 dB re 1V/Pa). Power sensitivity:
PZM-11: –45.5 dBm/Pa*
PZM-11LL: +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:
PZM-11: 120 dB SPL produces 3% THD.
PZM-11LL: 100 dB SPL produces 3% THD. Output connector: Three screw terminals. 1 = ground, 2 = audio hot (in polarity), 3 = audio cold (opposite polarity). Polarity: Positive pressure on the diaphragm produces a positive voltage on screw terminal 2 with respect to screw terminal 3. Operating voltage:
PZM-11: Standard phantom power, 12 to 48V DC on screw terminals 2 and 3 with respect to screw terminal 1.
PZM-11LL: 24V AC, 12-14V DC, or phantom power as the PZM-11LLS2. Current drain:
PZM-11: 400 microamperes.
PZM-11LL: 4 milliamperes.