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photo of Sound Choice Model SC-186K transmitter

Sound Choice Model SC-186K Infrared Audio Transmitter
(actual size: 6 1/2" wide x 5" deep x 1 3/4" high)


  • Completely self-contained transmitting system covers about 2500 square feet.
  • Instant setup - no microphones to attach, no controls to set.
  • Small portable size 6 1/2" x 5" x 1 3/4" (16.5 cm x 12.7 cm x 4.5 cm) 1.4 lbs. (0.63 kg)
  • Built-in Sound Choice Special Design boundry effect microphone or by special order, Crown PZM® microphone - the best microphone technologies available for wide-area sound pickup.
  • High-gain, low-noise BiFET preamplifier circuitry.
  • Automatic Gain Control continuously adjusts transmission volume.
  • Peak Limiter automatically prevents loud sounds from causing distortion. Instant response time catches even unexpected events.
  • Multiband internal audio equalization for improved intelligibility.
  • Genuine natural wood enclosure over an internal aluminum chassis.
  • Highly efficient wide-area infrared LED emitter system. Infrared transmission insures confidentiality. Much smaller than LED array panels.
  • Availble in all standard infrared transmitting frequencies.
  • External microphone/line input jack for transmission of other sound sources.
  • Line output jack for making transcription recordings.
  • Powerful, cool-operating internal digital switching power regulator.
  • Includes UL approved AC wall block transformer.
  • Optional SC-360 Emitter Disk transmits in a 360 degree pattern.
  • Optional SC-RMS Remote Mute Switch for conversational privacy.


The Sound Choice Model SC-186K is a compact wireless infrared audio transmitting system. The unit is completely self-contained and includes a super-sensitive Sound Choice Special Design or Crown PZM® microphone (by special order). Its high gain internal pre-amplifier makes even the faintest sounds audible. The Sound Choice Model SC-186K system incorporates a powerful infrared emitter which broadcasts audio over invisible infrared light waves. The infrared transmission is received by high-gain headsets worn by those needing hearing assistance. Styled in a dignified finished wooden enclosure, the transmitter blends with both traditional and modern government, courtroom or commercial settings.

The Sound Choice Model SC-186K system has built-in equalization circuits which de-emphasize the undesirable rumble of air conditioners, traffic and fans while emphasizing frequencies that contribute to the crispness and intelligibility of speech. Its built-in compressor/peak limiter automatically adjusts the volume so that speakers in close proximity to the unit will not cause distortion in the receivers. Distant speakers are automatically boosted in volume, while unexpected peaks are instantly attenuated.

The SC-186K has the ability to integrate into an existing sound system or utilize the unit's own highly sensitive self-contained microphone. There is also an output jack included for transcription recording.


photo of rear input/output control panel of SC-186K

Rear View (actual width is 6 1/2 inches)


  • Courtrooms
  • Government Hearing Rooms
  • Classrooms
  • Small Auditoriums
  • Nursing Homes
  • Conference Centers
  • Libraries
  • Corporate Meetings
  • Conference Rooms
  • Medical Conferences
  • Lecture Halls
  • Museums
  • Hotels
  • Convention Centers
  • Descriptive Narrative for the Blind
  • Simultaneous Lanuguage Translation


  • Microphone: Sound Choice Special Design (standard) or Crown PZM-11 capsule (special order at extra cost)
  • Preamplifier: Low-noise BiFET circuitry with automatic gain control and peak limiting
  • 1/4" Input Jack switchable for mic or line levels (unbalanced)
  • 1/4" Line Output Jack (unbalanced)
  • BNC Connector for optional 360 degree Emitter Disk
  • MiniDIN Connectors for optional Remote Mute Switch and Slave Transmitter
  • Equalization: Low end rolloff below 150 Hz; 50 microsecond pre-emphasis
  • Infrared transmission: 880 nm, IEC 764 Standard 95 kHz, 250 kHz, 2.3 mHz or 2.8 mHz FM optical carrier (please specify carrier frequency when ordering; 250 kHz standard)
  • Optical output: main IR beam greater than 450 mW; 120 degree beam dispersion
  • AC Power requirements: 125 volts AC to 16 volts AC, 1 Amp UL approved wall block transformer (included)
  • Dimensions: 6 1/2" x 5" x 1 3/4" (16.5 cm x 12.7 cm x 4.5 cm); 1.4 lbs. (0.63 kg)


SC-186K functional block diagram


Please click for the architectural and technical engineering bid specifications: html or .pdf format


pdf icon Please click for the SC-186K manual in .pdf format

PZM® is a registered trademark of Crown International, Inc.
The SC-186K uses technology developed by
Synergy® Electronic Music, Inc. and licensed exclusively to Sound Choice Assistive Listening, Inc.
Made in USA
US Patent Nos. 5,548,654 and 5,596,648
Specifications subject to change without notice.

Sound Choice Assistive Listening, Inc.
498 Long Hill Road
Gillette, New Jersey 07933 USA
toll free: 877-896-5048
908-647-2650 fax: please call for fax number

Pennsylvania numbers: 215-230-8600 fax: please call for fax number