MODEL SPX-1 MICROPHONE SPLITTER/MIXER
Designed for court and government applications, the Sound Choice model SPX-1 Microphone Splitter/Mixer couples the Sound Choice SC-186K Assistive Listening Transmitter, or other assistive transmitters, to existing four-track transcription recording systems without compromising the recording system or requiring unusual setup modes on often found on these recorders. The recorder continues to be operated in its usual manner.
The Splitter/Mixer passes audio signals and phantom power from each of four discrete microphone lines directly out to the transcription recorder. At the same time, audio from each of the mic lines is buffered and transparently split off from each of the discrete lines. The mic line splits are actively mixed to mono line level outputs which are routed to the External Line Input jack on the SC-186K Infrared Audio Transmitter. A second line output may be used to simultaneously feed a sound reinforcement system, broadcast line feed, or a single track recorder. Multiple Splitter/Mixer boxes may be cascaded together to provide for more than four mic lines while still generating a single final line output. Microphone inputs and outputs are balanced XLR connectors. 1/4" TRS balanced phone jacks are used for line level outputs and the cascade line input. The unmixed direct mic lines will continue to pass signal even if the SPX-1's power is turned off.
The line level outputs only may be silenced during sidebar or other private discussions using a front panel mute switch which has a flashing reminder indicator. The SPX-1 may also be ordered with a front panel remote mute mini-DIN connector in place of the mute switch. In this configuration the SPX-1 can be muted remotely using the Sound Choice SC-RMS Remote Mute Switch, available as an extra-cost option. Operating power is supplied by a UL/CSA approved low voltage transformer.
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
CHOICE ASSISTIVE LISTENING,
ENGINEERING AND PURCHASING SPECIFICATIONS:
The audio device shall perform the combined operations of a 4 channel microphone line splitter with 4 direct feed-through outputs, and a 4 input microphone mixer and preamplifier. Each of 4 microphone lines shall have a female XLR balanced input and a male XLR balanced direct output. There shall be no audible crosstalk between the lines having isolation greater than 80 dB between lines. Each individual microphone direct line shall be capable of passing phantom microphone power in either direction without transferring phantom power to any other unpowered microphone line. Each individual microphone direct line shall be capable of passing microphone audio and phantom power even when the mixer section is unpowered.
The split branch of each microphone line shall be of a buffered nature and of such an impedance that the source microphone signal shall remain unattenuated. The split branches of each microphone line shall be internally level adjustable, combined (electrically summed) and gain amplified at least 60 dB with a signal to noise ratio of 70 dB or better. A line level +4 dBm balanced input via a TRS 1/4" jack shall be combined with the mic lines so that multiple splitter/mixer devices may be cascaded together to provide for additional microphone inputs. The combined output shall be at a standard +4 dBm 600‡ line level available at 2 balanced TRS 1/4" jacks. A master output volume control shall be provided.
A switch and a visual indicator means shall be provided for muting the combined mixer line outputs when necessary to a level of at least -70 dB below the unmuted signal level. The muting circuit shall not affect the signal of the unmixed microphone lines routed to the direct outputs. The muting circuit shall not create undue clicking or other electrical noise when changing operational states.
The enclosure shall incorporate full RF shielding. Low voltage power shall be provided by UL/CSA approved transformer.
The Sound Choice Assistive Listening, Inc. model SPX-1 Splitter/Mixer is specified.
SOUND CHOICE ASSISTIVE LISTENING,