© Copyright 2014 Hall Research, Inc.
All rights reserved.
HDMI Audio Extractor w/ EDID Mgmt
1.0 Introduction
Thank you for purchasing the Hall Research EMX-HD-AUD. Use this device to extract the
audio from any HDMI video signal for connection to audio equipment. The HDMI signal is
reconditioned and boosted as it passes through the device, so it can also serve as an
extender. The audio extractor also features EDID management (pass-thru or emulate), So it
can emulate any HDMI display and is capable of extracting the audio even if no actual display
is connected to the output. Both Toslink (digital) and two channel stereo analog outputs are
available on the device. The EMX-HD-AUD is an HDMI transceiver, so it not only re-clocks
the video data, it also separates and buffers the DDC channel on which EDID and HDCP are
communicated. This can often resolve system-level HDMI signal-chain issues since the EMX-
HD-AUD acts as an intelligent intermediary.
The EMX-HD-AUD can be powered from the HDMI source connected to its input and no
additional power supply connection is needed for most applications.
The package includes a universal power supply in case the power from the HDMI input
source is insufficient. The power supply is plugged in at the USB connector. When the USB
port is connected to a PC (cable supplied), the unit is powered by the PC through the USB
connection.
The EMX-HD-AUD also provides useful diagnostic information that can help is resolving
compatibility of components in the video signal chain.
Multi-color LEDs on the unit indicate the mode of operation with regards to EDID routing, and
also provide real-time status on the HDMI video and audio signals. For example the LEDs can
identify presence of audio and whether it is 2-channel or multi-channel. Similarly the detection
of video from source is indicated and it identifies whether there is HDCP on the video or not.
When connected to a PC via the USB port, further details about the HDMI signal is available.
The extracted audio is output as analog stereo on a standard 3.5mm connector as well as in
digital audio format (SPDIF) on an optical Toslink connector. Normally the audio is left intact
on the HDMI output, however the user can remove or mute the audio that is on the HDMI
output. Doing so may be advantageous in applications where the connected TV’s speakers
may be causing interference or echo due to the delay in the audio heard from the TV. Muting
the audio output from the HDMI would ensure no sound is heard from the TV even if its
volume is turned up.
The EMX-HD-AUD constructs an EDID table (capabilities list) for the connected source. This
table is either copied verbatim from the connected display when the unit is in Pass-thru mode,
or substitutes an internal EDID data from on board memory when in Emulate mode. The
internal EDID data can be learned from any connected display by using the buttons on the
box. EDID data can also be uploaded to the EMX-HD-AUD from a PC via the USB port. The
device maintains HDCP compliance regardless of the EDID routing mode, so HDCP protected
content passes through the system with protection intact even when the EDID is emulated
from internal memory.
