RME ADI-648 [12/32] The adat to madi converter

User's Guide ADI-648 © RME

7. The ADAT to MADI Converter

7.1 General

This part of the ADI-648 converts ADAT optical to MADI. ADAT optical carries 8 channels of 24

bit audio at up to 48 kHz sample rate, 4 channels at up to 96 kHz, and 2 channels at up to 192

kHz. Transmission is done via a single optical line (TOSLINK). The length of the optical cable is

limited to about 10 m.

Because the Sample Split (S/MUX, S/MUX4) format doesn't contain a coding, the ADI-648 can-

not distinguish it from normal (44.1/48 kHz) material. Whether the MADI output is supposed to

work in 96K Frame mode has to be set explicitly by the user.

The inputs can be used in any combination, e. g. it is sufficient to connect an input signal only to

input 3. In slave mode, this input is automatically being used as clock source. If more than one

signal is present, the one furthest left is being used as clock source, i. e. the active input with

the lowest number.

The 8 ADAT optical inputs are transferred to a 64-channel MADI output. Furthermore, the ADI-

648 contains an easy-configurable 8-channel 16x16 Matrix Router. Any of the outputs, which

are divided into 8-channel blocks, can be fed from any 8-channel input block, both on the ADAT

and the MADI side. With this, there is not only free routing within the ADAT to MADI conversion,

but also splitting and routing within the same format.

7.2 Inputs

The ADAT optical inputs of the ADI-648 are fully compatible with all ADAT optical outputs.

ADAT input 8 is used to switch the MADI output format from 56-channel to 64-channel mode.

When ADAT input 8 does not receive a valid input signal, the ADI-648 generates a 56-channel

MADI signal. When feeding a valid input signal, a 64-channel MADI signal will be generated.

This rule is also true when 96K Frame mode is active. Then 28 or 32 channels will be available.

Since firmware version 2.5 the current Matrix configuration also influences the output mode. If

MADI output group 8 is assigned to any input, the device generates 64 channel format. This is

also true when MATRIX STATE is set to OFF. As this channel assignment is factory default, all

ADI-648 will generate 64 channel mode as default mode. To activate the 56 channel format for

the MADI output, the MADI output group 8 has to be set to Mute, and no signal must be present

at ADAT input 8.

7.3 Input State Display

The input state is being displayed by means of 16 LEDs. A missing or invalid input signal is

indicated by flashing of the SYNC LED. When using multiple inputs in clock mode ADAT

INPUT, the input with the lowest number is being used as clock source. In case ADAT is not

chosen as clock reference, SyncCheck takes the chosen clock (internal, external, MADI) as

reference and compares it to the clocks of the inputs. Non synchronous inputs will be indicated

by flashing of the corresponding SYNC LED. A missing or invalid input signal will be displayed

by blinking of the ADAT INPUT CLOCK LED.

Audio data present in the input channels are signalled by an AUDIO LED per input. As the ADI-

648 operates in 8-channel blocks, an AUDIO LED will show audio data from 8 channels simul-

taneously. The green LED is lit as soon as one of the channels of an 8-channel block contains

audio data, means is no longer digital zero.