RME Audio Digiface Ravenna, User Manual, Page: 69 / 73

User's Guide Digiface Ravenna
© RME
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Single Wire
Standard audio data transfer, where the audio signal's sample rate is equal to the rate of the
digital signal. Used from 32 to 192 kHz. Sometimes called
Single Wide .
Double Wire
Before 1998 there were no receiver/transmitter circuits available that could receive or transmit
more than 48 kHz. Higher sample rates were transferred by splitting odd and even bits across the
L/R channels of a single AES connection. This provides for twice the data rate, and hence twice
the sample rate. A stereo signal subsequently requires two AES/EBU ports.
The Double Wire method is an industry standard today, however it has a number of different
names, like
Dual AES , Double Wide , Dual Line and Wide Wire . The AES3 specification uses
the uncommon term Single channel double sampling frequency mode . When used with the ADAT
format, the term S/MUX is commonly used.
Double Wire not only works with Single Speed signals, but also with Double Speed. As an exam-
ple, Pro Tools HD, whose AES receiver/transmitter only work up to 96 kHz, uses Double Wire to
transmit 192 kHz. Four channels of 96 kHz turn into two channels of 192 kHz.
Quad Wire
Similar to Double Wire, with samples of one channel spread across four channels. This way single
speed devices can transmit up to 192 kHz, but need two AES/EBU ports to transmit one channel.
Also called
Quad AES .
S/MUX
Since the ADAT hardware interface is limited to Single Speed, the Double Wire method is used
for sample rates up to 96 kHz, but usually referred to as S/MUX (Sample Multiplexing). An ADAT
port supports four channels this way. With MADI S/MUX is used as well, to transmit up to 96kHz
although the 48K Frame format is used.
S/MUX4
The Quad Wire method allows to transmit two channels at up to 192 kHz via ADAT. The method
is referred to as S/MUX4. With MADI S/MUX4 is used as well, to transmit up to 192 kHz although
the 48K Frame format is used.
Note: All conversions of the above described methods are lossless. The existing samples are just
spread or re-united between the channels.
48K Frame
Most often used MADI format. Supports up to 64 channels at up to 48 kHz.
96K Frame
Frame format for up to 32 channels at up to 96 kHz. The advantage of this format against 48K
Frame using S/MUX: the receiver can detect the real (double) sample rate on its own and imme-
diately. With 48K Frame and S/MUX, the user has to set up the correct sample rate in all involved
devices manually.