Shure SM12A Headworn Microphone

SM12A Headworn Microphone description:

The Shure Model SM12A Professional Head-Worn Microphone with Receiver is a low-impedance, unidirectional, dynamic microphone with an integral earphone assembly. Designed for sports and news announcing, interviewing and intercommunication systems, and for special events remote broadcasting, the SM12A offers convenient, hands-free operation without user fatigue. Drummers, keyboard artists and other musicians who need a vocal microphone -- one that will not pick up unwanted sounds -- will find the SM12A's smooth, natural voice frequency response and noise cancellation ideal for their applications. A close-talking unit, the SM12A may be used under noisy conditions without loss or masking of voice signals.

The SM12A is a small, lightweight, rugged and reliable unit, with provisions for mounting to a supplied dual spring steel headband. A pivot housing per-mits the microphone boom to be moved 20 degrees in any direction, and the distance between the microphone and pivot to be changed by up to 89 mm (31/2 in.). The receiver ear tube, attached to the bottom of the pivot housing, may be moved through a 55 degree arc. A miniature windscreen to protect against wind noise and explosive breath sounds, and two connector belt clips are also supplied.

Features:

• Close-talk operation and unidirectional polar pattern for effective noise reduction
• Smooth natural voice frequency response
• Locking adjustment knob permits boom to pivot 20 degrees in any direction
• Boom length adjustment through 89 mm (3 1/2 in.) range
• Built-in receiver protection circuit automatically avoids excessive sound pressure level
• Receiver ear tube adjustable through 55 degree arc
• Light weight plus dual headband eliminate user fatigue
• Does not interfere with eyeglasses
• Ruggedly constructed of stainless steel, aluminum and high-impact thermoplastic
• Convenient, secure clips attach connectors to belt or clothing

Specifications:

• MicType: Dynamic, Close-Talking
• Frequency Response At 8 mm (5/16 in.): 50 to 15,000 Hz
• Polar Pattern: Cardioid (unidirectional) response-uniform with frequency, symmetrical about axis
• Impedance: Microphone rating impedance is 150 ohms (200 ohms actual) for connection to microphone inputs rated at 19 to 300 ohms
• Sensitivity (close-talked at 1,000 Hz): Open Circuit Voltage –67.0 dBV/Pa (.45 mV)/(1 Pa = 94 dB SPL)
• Hum Sensitivity (typical): 38.4 dB equivalent SPL in a 1 millioersted field
Phasing: Positive pressure on diaphragm produces positive voltageon pin 2 of microphone connector
• Connector: Male XLR audio connector (TA3M)
• Receiver/Earphone Type: Dynamic
• Frequency Response: 70 to 12,000 Hz
• Impedance: 2,000 ohms at 1 kHz (200-ohms cartridge with matching transformer in phone plug)
• Output Level: 105 dB SPL with 1.4V at 1 kHz (1.0 mW into 2 cc cavity)
• Phasing: Positive voltage on phone plug tip produces positive pressure in ear tube
• Connector: Phone plug (contains matching 200:2,000 ohm transformer)
• General: Cable Non-detachable, 1.5m (5 ft), four conductor, shielded, plastic-jacketed; additional 762 mm (2.5 ft), two-conductor receiver cable attached to micorphone connector