• Registered: 2011-10-22
  • Posts: 19

Topic: Double Speed & S/MUX channel numbering

I am using a HDSPe MADI FX with a M-1610 Pro and A M-1620 Pro connected via separate Madi ports.

I want to future proof the routing for 96k.

So, at 96kHz sample rate, Madi only carries 32 channels, so only the FIRST 32 channels are transmitted, as numbered within TotalMix for example? Channels 33-64 are deactivated? Or is it only uneven channels?

Similarly, how will S/MUX work for ADAT? Currently I am using 16 channels of ADAT outputs on the M-1610, on  ADAT ports 1 and 2. When switching to 96kHz, will it simply use ADAT ports 3 and 4 as well, but the channel numbering stays the same?

HDSPe MADI fx, M-1620 Pro, M-1610 Pro, UFX Plus, UFX II, Babyface Pro fs

crimsonnoise's Website

2 Reply by ramses (edited by ramses 2024-12-26 17:33:36)

  • ramses
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  • Registered: 2012-10-14
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Re: Double Speed & S/MUX channel numbering

For all digital channels which are not 2ch protocols "by nature" - like AES and SPDIF - double and quad speed need to use double / quad amount of channels to achieve the necessary bandwidth demands for the higher sample rates.

As the transmission speed is always the same, you have to multiplex data between multiple channels for ADAT and MADI.
Therefore, the total number of channels is less with double / quad speed.

Example UFX III:

@single speed
   ADAT1 (ADAT protocol): ADAT ch 1..8
   ADAT2 (ADAT protocol): ADAT ch 9..16
   ADAT1 (SPDIF protocol): ADAT ch 1..8 (but only 1/2 useable for SPDIF, as it is 2ch protocol)
   ADAT2 (SPDIF protocol): ADAT ch 9..16 (but only 9/10 useable for SPDIF, as it is 2ch protocol)
   AES: AES ch 1..2
   MADI (64 ch format): MADI ch 1..64

@double speed
   ADAT1 (ADAT protocol): ADAT ch 1..4
   ADAT2 (ADAT protocol): ADAT ch 5..8
   ADAT1 (SPDIF protocol): ADAT ch 1..4 (but only 1/2 useable for SPDIF, as it is a 2ch protocol)
   ADAT2 (SPDIF protocol): ADAT ch 5..8 (but only 5/6 useable for SPDIF, as it is a 2ch protocol)
   AES: AES ch 1..2
   MADI (64 ch format, 96k frame): MADI ch 1..32

@quad speed
   ADAT1 (ADAT protocol): ADAT ch 1..2
   ADAT2 (ADAT protocol): ADAT ch 3..4
   ADAT1 (SPDIF protocol): ADAT ch 1..2
   ADAT2 (SPDIF protocol): ADAT ch 3..4
   AES: AES ch 1..2
   MADI (64 ch format, 96k frame): MADI ch 1..16

BR Ramses - UFX III, 12Mic, XTC, M-1620 Pro D, RayDAT, ADI-2 Pro FS R BE, X10SRi-F, E5-1680v4, Win10
  • Registered: 2011-10-22
  • Posts: 19

Re: Double Speed & S/MUX channel numbering

Thank you for this! For the UFX III it looks reasonable, as it has only one Madi in/out.

I couldn't find a similar documentation for the HDPe Madi FX so I conducted a test at 96kHz, and unfortunately, all the names and numbers are jumbled up:


@single speed
MADI 1 (optical): MADI 1-64
MADI 2 (optical): MADI 65-128
MADI 3 (coax): MADI 129-192

@double speed
MADI 1 (optical): MADI 1-32
MADI 2 (optical): MADI 33-64
MADI 3 (coax): MADI 65-92

This necessitates completely different Totalmix snapshots or workspaces with different channel naming, when switching to 96kHz. I found there is already a discussion for this here, and the OP made a good suggestion: "create an option in the driver to keep the channel numbers CONSTANT. So when the user goes to 96k, we'll still have 1-64 be allocated to the first MADI device, but 33-64 will be dummy/no audio. "

https://forum.rme-audio.de/viewtopic.php?id=40789

HDSPe MADI fx, M-1620 Pro, M-1610 Pro, UFX Plus, UFX II, Babyface Pro fs

crimsonnoise's Website