- 4 -
MADI stream
to FOH / control room
Why MADI?
With its architecture directly related to the AES3 (AES/EBU)
audio protocol and its widely available consumer equivalent
S/PDIF, MADI is a format that provides sim-plicity, extremely
low latencies and ease of use across short and long distances.
MADI is designed to send up to 64 audio channels at 48kHz
sampling frequency (32 channels at 96kHz, 16 channels at
192kHz) from one device to another device in a unidirectional
data stream. This distinguishes MADI signals from so-called
“network audio protocols” that require user interaction to
send audio signals between several audio devices once they
have detected each other in a local area network.
The fact that MADI is a point-to-point protocol simplifies the
design of digital audio devices, and brings several benefits
for the user:
• Audio devices with MADI such as A/D or digital format
converters, computer audio interfaces and others
have incredibly low boot up times of usually less
than 5 seconds from power on to full operability and
signal processing
• An audio signal of up to 64 channels, 24 bit, 48kHz is
detected by the receiving device in the blink of an eye
• The latency between two MADI equipped digital
devices is extremely low compared to network audio
formats (commonly less than three samples - equivalent
to 62.5 µs)
• A minimum amount of configuration is required, after
that, it’s all plug and play
• Devices can be configured stand-alone, all routings and
channel assignments are static and independent of an
existing connection to another device
• MADI devices perform consistently, regardless of how
many devices are connected
• Malfunctions can quickly be traced and resolved, for
example by using RME’s free DIGIcheck application.
The Multichannel Audio Digital Interface was created as
an open standard (AES-10) and has, since its creation,
been implemented in the audio devices of countless
manufacturers worldwide. Its wide acceptance through-out
the industry makes it a safe investment wherever a large
number of audio channels need to be transmitted.
MADI - cable basics
In its current revision, the MADI standard suggests two
types of cables, optical and coaxial. Both have been
supported by RME since 2003, when RME released its first
MADI computer interface card HDSP MADI, and its first
ADAT-MADI converter ADI-648.
A third type of cable, known from common computer
networks, is called “twisted pair” (CAT5e or higher) and has
the advantage of providing additional capacity for the
transport of DC voltage. At the time of writing, this cable
type is not part of the MADI standard and is therefore
implemented by manufacturers in different ways.
All cables carry the same information and achieve the
same signal quality, the type of cable is therefore a
question of convenience, budget and compatibility.
Optical cables have the advantage of being galvanically
isolated, extremely lightweight and available in lengths of
up to 2000m. 75 ohms coaxial cables are robust, feature a
locking mechanism and are widely in use for word clock
and video cabling.
They normally bridge distances of up to 100m. Twisted pair
cables are very affordable and often already integrated
into the existing building infrastructure. Depending on
the classification of the cable, lengths of more than 150m
can be used.
While the optical and coaxial ports provide independent
input and output connectors, the RJ45 connector for
twisted pair cables integrates both input and output in
one plug. For this reason there are two ports on devices
where several units might be connected in a chain.
In a MADI system, each device detects the complete 64
channel stream at its input, and creates a new stream
at its output to send it to the next device. If some
channels should be passed on through a device, they
are simply copied from input to output without any
alteration by the device.
On the following pages, you are guided through some
common MADI systems - please keep in mind that
each product may be used in a variety of different ways.
Contact your local RME dealer for a tailor-made setup to
fit your needs!
REC
USB Computer Interface
Microphone Preamp:
OctaMic XTC
Summary of Contents for MADI Converter
Page 1: ...Usage and Applications...
