• Moin
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Topic: Can a MADI Router cause signal distortion?

Greetings!

Since May I’m using different RME devices for recording classical concerts. Sporadically, my 12Mic flashes a red warning (input and clock) for a second, then erverything goes back to normal. Today, I installed a test setup, so I could check if there is any impact to the signal.

The setup: a UFX+ and a 12Mic are both connected to the MADI Router via fiber. The output from the UFX+ goes fullstream to the 12Mic, from the 12Mic back to the UFX+ via a matrix (so I got a loop).

The 12Mic is clocked to MADI opt., the matrix uses the UFX+ as clock source, the UFX+ uses its internal clock. Everything is set to 48khz.

With Reaper I sent a test signal through the UFX+ -> MADI Router -> 12Mic -> MADI Router -> UFX+, where I recorded the result. After 10, maybe 15 minutes, I got the red warning on the 12Mic. The signal looks like this:

https://i.imgur.com/CWAQUnh.png

I have the impression that this only occurs if the Bit Transparency setting in the Router is set to "Activate MADI receiver". If it is set to "Bypass MADI receiver", no error occurs.

I have abolsutely no idea what the problem could be. Any help is appreciated!

– Alex

Fireface UFX+, 2× 12Mic, MADI Router, Digiface Dante
ThinkPad P15, ThinkPad T480s, Reaper
  • Max
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Re: Can a MADI Router cause signal distortion?

A matrix with the option "create new MADI subframes" and a wrong clock setting could distort the outgoing signals, yes.

Can you test the following:
There is a transparency setting called "pass MADI subframes", which should be active. Another relevant setting is the clock source for the matrix, which should be set to "Auto".
Finally, if you can still observe the problem, please test with a stream routing opt-opt and, to rule out a cabling issue, also coax-coax.

-Max

  • Moin
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Re: Can a MADI Router cause signal distortion?

Thank you for the quick response, Max!

First thing I did was checking your suggestions.
1. The option "Pass MADI subframes" was already activated.
2. The matrix was manually set to a device, so I changed it to "Auto Sync". Problem still not gone.
3. Changed all cables. Unfortunately, I only have two coax cables here, so the other connections got other fiber cables.

Today I tested some more setups. First, two direct connections without the router in between (error = sync loss):
1. UFX+ (master) -> 12Mic, direct via fiber = no errors.
2. UFX+ (master) -> 12Mic, direct via coax = no errors.

Then I added the router again, but without a matrix:
1. UFX+ (master) -> 12Mic, full stream routing = error every ~8.5 minutes.
2. 12Mic A (master) -> 12Mic B, full stream routing = error every ~8.5 minutes.
3. 12Mic A (master) -> UFX+ -> 12Mic B, full stream routing = error every ~8.5 minutes.
4. UFX+ (Master) -> Digiface Dante, full stream routing = connection seems stable.

Then I thought about the SFP modules in the 12Mics. At time of purchase, the original RME SFP modules were not available, so I bought these: https://www.fs.com/de/products/23583.html. Maybe these are incompatible?

To rule that out, I connected the 12Mics via the coax cables:
1. 12Mic A (master) -> UFX+ = error every ~8.5 minutes.
2. 12Mic B (master) -> UFX+ = error every ~8.5 minutes.

In conclusion, it can’t be the SFP module, an incorrectly set matrix, faulty cables, a defective UFX+ or 12Mic (or both 12Mics have a problem -> SteadyClock FS?). To me it looks like the MADI router gets something wrong while processing the MADI data. Dont’t know if thats a possible explanation. Or I overlooked something obvious.

It took me hours to test all these things and I’m at the end of my knowledge. Easiest solution from my perspective would be another MADI Router for testing. I will contact the RME Support for further assistance.

In the mean time, I’m open for new ideas.

– Alex

Fireface UFX+, 2× 12Mic, MADI Router, Digiface Dante
ThinkPad P15, ThinkPad T480s, Reaper

4 Reply by Max (edited by Max 2022-11-28 09:40:35)

  • Max
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Re: Can a MADI Router cause signal distortion?

Moin Moin,

thank you for testing and reporting this!
The cause of this has been found and fixed with the following RC firmware:
https://forum.rme-audio.de/viewtopic.php?pid=194220

A bit of background info:

The MADI Router uses a slightly different architecture with a different "re-clocking" process. This process reduces jitter like SteadyClock, and also creates a valid MADI signal according to AES10, but the outgoing signal is still different from other RME devices that use SteadyClock.

The previous firmware of the 12Mic (and other AVB devices) changed SteadyClock to be more resilient when clocking to CRF (clock reference format) streams, which use a much lower frequency (500 Hz) to synchronize entities on a network to different sampling rates. What we did not notice in our tests is that this caused the phenomenon you discovered, which only showed up when receiving signals from a MADI Router with active MADI receivers.

Again, thanks for the thorough testing and detailed report - let us know if the firmware is working well for you!

Max
RME

5 Reply by ramses (edited by ramses 2022-11-28 11:14:25)

  • ramses
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Re: Can a MADI Router cause signal distortion?

Have no MADI router, but as UFX+ and 12Mic customer, many thanks to you and RME, making the products working solid in every situation / setup. Excellent work! :-)

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14
  • Moin
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Re: Can a MADI Router cause signal distortion?

Glad I could help in improving a RME product wink

Max wrote:

The cause of this has been found and fixed with the following RC firmware:
https://forum.rme-audio.de/viewtopic.php?pid=194220

After installing the update, everything worked as expected – no sync loss anymore. Thank you for the quick solution and technical details on the problem! I'll keep an eye on it and get back to you if I notice any other problems.

– Alex

Fireface UFX+, 2× 12Mic, MADI Router, Digiface Dante
ThinkPad P15, ThinkPad T480s, Reaper