Madi Modes; Pull Up And Pull Down Operations; Sample Rate Converters - Focusrite RedNet Installation Manual

MADI Modes

RedNet 6 supports both varispeed and non-varispeed MADI modes. Non-varispeed mode enables up
to 64 channels I/O at 48 kHz. Varispeed mode enables up to 56 channels I/O at 48kHz. The MADI input
of RedNet 6 will automatically detect the channel count of incoming signals, meaning the user does
not need to adjust any settings. When 'Follow Rx' (located in MADI Output menu) is set, the MADI
output of RedNet 6 will automatically be set to match the incoming MADI signal.
The RedNet 6 MADI input select is auto sensing by default although manual override is provided in
the RedNet Control application. When Auto mode is selected and both coaxial and optical inputs are
present, RedNet 6 will automatically prefer the optical input. If the optical cable is removed from the
RedNet 6 input, the unit will automatically switch to the coaxial input. If auto input is selected while
no valid coaxial or optical input is present, both the optical and coaxial input indicators will flash.
The RedNet 6 MADI output has three varispeed states selectable in the RedNet Control application:
• Varispeed
• Fixed
• Follow MADI input
In addition to the varispeed states the RedNet 6 MADI output is capable of a range of sample rates.
These can be selected in the RedNet Control application:
• Single (44.1 or 48 kHz)
• Dual (88.2 kHz or 96 kHz)
• Quad (176.4 or 192 kHz)
• Follow MADI input
When a MADI input is present, the MADI output of RedNet 6 will automatically match the MADI input.
Pull Up and Pull Down Operation
RedNet devices are able to run with pull up or pull down sample rates in one of two ways:
• Locking to an external clock at the desired clock frequency
• Operating at a specified pull up or pull down percentage as selected in the Dante Controller
application*
* Note: Not all RedNet devices currently support this mode of operation.
During 64 channel (i.e. non-varispeed mode) operation, MADI is not capable of operating at greater
than approximately +1% of the nominal sample rate. This may become a problem when the network
clock domain is pulled up beyond 1% of nominal. In this condition, the Output Varispeed indicator on
the front panel will flash to indicate that the output is out of MADI tolerance. Therefore to continue
generating a valid RedNet 6 MADI output it would be necessary to operate the MADI output in 56
channel (varispeed) mode, use sample rate conversion or reduce the network rate to within 1% of
nominal sample rate.

Sample Rate Converters

RedNet 6 has sample rate converters on both its inputs and outputs allowing the network and MADI
domains to have sample rates which are independent of each other.
This can be particularly useful in post production environments where the network audio is pulled
up or down, but it is necessary to have the MADI stream run at a base sample rate to interface,
for example, with a mixing console. Engaging the RedNet 6 sample rate converters will however
increase the overall latency of the device.
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