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User's Guide HDSP MADI

 © RME

 

 

 
Single Speed 
Sample rate range originally used in Digital Audio. Typical applications are 32 kHz (digital radio 
broadcast), 44.1 kHz (CD), and 48 kHz (DAT). 
 
Double Speed 
Doubles the original sample rate range, in order to achieve higher audio quality and improved 
audio processing. 64 kHz is practically never used, 88.2 kHz is quite rare in spite of certain ad-
vantages. 96 kHz is a common format. Sometimes called Double Fast. 
 
Quad Speed 
Controversially discussed way of ensuring hi-end audio quality and processing by quadrupling 
the sample frequency. 128 kHz is non-existant, 176.4 kHz is rare, if at all then 192 kHz is used, 
e.g. for DVD Audio. 
 
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 ex-
ample, 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 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.