Appendix D: Audio - Avocent Emerge MPX Installer/User Manual

Appendix D: Audio

The HDMI media module for MPX1000 extenders offers support for embedded digital audio and
unbalanced analog audio via left and right RCA jacks. The HD15 media module supports only
unbalanced analog audio. Analog audio is sampled at 48Khz, which is CD quality audio.
NOTE: With MPX1000 units you have received two snap-on ferrites. If you are using the analog audio (RCA
Jacks) these ferrites should be applied to each end of the cables. Apply the ferrites approximately one inch from
the cable ends. One ferrite goes around both cables.
MPX1500 extenders offer embedded HDMI digital audio as well as unbalanced analog audio via
left and right RCA jacks. Snap on ferrites are not required for the use with MPX1500 extenders.
Depending upon your firmware version, the MPX1500 receiver may or may not support coaxial
and optical digital audio (S/PDIF).
Because transmitters and receivers can be configured for differing media types, a variety of
configurations are possible. The following sections provide detailed information regarding these
additional configurations.
Digital Source Device Considerations
When an HDMI source is received, the MPX transmitter ignores the external analog audio jacks
and passes the embedded digital audio signal. When a DVI-D signal is received, the transmitter will
accept audio input from the RCA jacks. In both cases, audio will be output by the receiver in the
form of embedded digital audio and external analog audio.
NOTE: If the primary receiver is attached to a VGA or DVI-D display, the EDID information provided by the
display will disable digital audio at the source device. In this case, the transmitter will pass analog audio even if
the source device connection is HDMI. Thus, if digital audio is required, be sure to select a receiver attached to
an HDMI display device.
NOTE: If the digital audio embedded within the HDMI signal is 96KHz, then analog output on the receiver
modules will be disabled. Digital audio will continue normally.
Analog Source Device Considerations
A transmitter that is accepting analog video will always input audio on the dual RCA jacks. When
passed to a receiver with an attached HDMI display device, the audio will be embedded within the
HDMI signal and also available on the dual RCA jacks.
When analog video devices are attached to both the transmitter and receiver, audio will be present
only on the dual RCA jacks.
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