Switch Back M8RX User Guide 3
CONTROLS
The M8RX has three different types of controls:
1. INPUT VOLUME KNOB – There are 3 input
volume knobs labeled “A”, “B”, and “C”. Each of these knobs
has two parts that can be adjusted independently: a tip
and a ring. The tip of each volume knob adjusts the level of
each analog input located on the bottom of the M8RX. The
ring of each volume knob adjusts the level of each Dante
input which arrives over the Ethernet network connection.
These can be assigned from any other Dante device on the
network using the Dante Controller software. These volume
knobs only adjust the audio level to the headphones, they
do not affect the audio level sent to the Dante network.
2. MASTER VOLUME KNOB – The master volume is used
to set the overall volume level of the headphone output.
3. INPUT GAIN PUSH BUTTON – Each button is
located below its respectful channel’s XLR inputs on the
bottom of the M8RX. Pushing one of these buttons will
display the current input gain for the chosen input on the
5 GREEN LED indicators below and between the two
XLR inputs. Every press of this button after the initial press
will step the gain up or down one step. The gain first steps
up until it gets to the top, and then it steps back down until
it gets to the bottom and continues to repeat this pattern.
Gain has input sensitivity adjustments from -54dBu to
-30dBu for XLR microphone inputs (-36dBu to -12dBu for
¼” inputs). Holding one of these push buttons for 2 seconds
will toggle the phantom power for the input which is
indicated by an ORANGE LED below the XLR input .
Pushing and holding both of these buttons at the same time
will cycle through colors on the font color-changing LED .
These buttons can also be locked or unlocked (see page 4).
INPUTS
The M8RX has three different types of inputs:
1. BALANCED MONO INPUT – The M8RX has two balanced
mono inputs labeled “A” and “B” . These inputs have
a special “combo” connector that allows either a XLR
microphone connector or a ¼” TRS connector. The XLR
input is designed for microphones and has adjustable input
gain with sensitivity adjustments from -54dBu to -30dBu
and a 48 volt phantom power supply that is selectable
per input. The ¼” input has an 18 dB pad and is designed
for line-level and instrument inputs with input sensitivity
adjustments from -36dBu to -12dBu. These two inputs can
be monitored locally in the analog domain (zero latency)
by turning up the tips of volume knobs “A” and “B”
respectively. These inputs are also available on the Dante
network as channels 1 and 2.
2. UNBALANCED STEREO INPUT – The M8RX has one
unbalanced stereo input on a 1/8” TRS connector labeled
“C” . This input is designed for line-level sources and
has a fixed input gain sensitivity of -10dBu. This input can
be monitored locally in the analog domain (zero latency) by
turning up the tip of volume knob “C” . This input is also
available on the Dante network as channels 3 (left) and 4
(right).
3. DANTE DIGITAL INPUT – The M8RX has 3 channels of
digital audio inputs from the Dante network. These can be
monitored using the rings on volume knobs “A” , “B” ,
and “C” . The first two inputs are mono and audio can
be routed to them using the Dante Controller software
on channels 1 and 2 of the M8RX. Dante input “C” is a
stereo input and audio can be routed to it using the Dante
Controller software on channels 3 (left) and 4 (right).
Note: If Dante sampling rates 88.2kHz or 96kHz are used,
only 2 channels of audio are supported: “A” and “B”.
MIXER CONSTRUCTION
The Switch Back M8RX is constructed of UV-stabilized ABS
and has a built-in standard camera tripod stand mount (1/4”-20
thread). A belt-clip with tripod threaded screw is included so that
the M8RX can be attached and worn on a belt. Additionally, a
tripod thread to microphone stand adapter (1/4”-20 to 5/8”-27) is
also included to allow mounting on a microphone stand.
STATUS INDICATORS
The M8RX has seven types of status indicators:
1. FRONT COLOR-CHANGING LED – A large color-
changing indicator is provided to allow easy identification
when multiple Switch Back M8RX interfaces are used in
a setup. The color of this indicator is user-selectable by
using the PC or MAC software (available for download
from www.hearback.com) or by pressing both input buttons
simultaneously for several seconds. This indicator will
also automatically cycle through the color spectrum when
booting and also when the identify function is triggered in
the Dante Controller software.
2. DANTE – The Dante bus has three indicators that are
bi-color. They are BLUE under normal operating conditions
and RED alerting the user a problem exists. The SYS
indicator is BLUE if at least one other Dante device is
connected to the same network, otherwise it is RED. The
SYNC indicator is BLUE if the internal clock circuitry
is operating properly, otherwise it is RED. The ERR
indicator is normally off. If there is a problem with the
firmware or memory then the ERR indicator will turn RED.
3. GAIN – Five GREEN indicator LEDs located below and
between the XLR input connectors will illuminate when one
of the input buttons is pushed (located below each XLR
input). These indicators display the current input sensitivity
for each input from -54dBu to -30dBu for XLR microphone
inputs (-36dBu to -12dBu for ¼” inputs). These indicators
will automatically turn off after a few seconds of pressing
one of the input buttons.
4. PHANTOM POWER – a single ORANGE LED
indicator is located below each XLR input with the label
“48v” below it. When illuminated, 48 volts DC is present
on XLR pins 2 and 3 with respect to pin 1. This provides
power to any microphones requiring phantom power. This
is toggled on or off by holding one of the input buttons for 2
seconds.
5. AUDIO SIGNAL – six indicator LEDs located below the
input volume controls illuminate BLUE when signal is
present and RED when the input is too strong and causing
distortion. 3 of these indicators represent the A , B ,
and C Dante inputs (red Dante logo above each) and 3
of these represent the A , B , and C analog inputs
(blue XLR logo above each).
6. HEADPHONE AMPLIFIER FAULT – The fault indicator
is normally off and only illuminates RED if an over-
current or short circuit condition occurs for a long enough
period to cause overheating of the amplifier (100°C or
212°F). Continued use of the amplifier in a fault condition
is not recommended as it can degrade the amplifier’s
performance and life.
7. DANTE FAILSAFE BUTTON – Accessible through a
small hole using a paper clip or small screw driver. Only use
this button if instructed by our technical support.
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