• Registered: 2021-04-29
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Topic: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

Hope some MADI experienced people can help.

How do I set up my M1610-Pro to auto switch to the RME MADI's current sample rate?

I have tried the following set up

A. Clock on the 1610 set to 48, MADI card set as master

MADI card set at 44.1: M-1610 will upsample to 48. Warning light appears on power button
MADI card set at 48: works as expected
MADI card set at 88.2: M-1610 will upsample to 96. Warning light appears on power button
MADI card set at 96: M-1610 works as expected

B. Clock on the 1610 set to 96kHz, MADI card set as master

MADI card set at 44.1: M-1610 won't sync at all. Warning light appears on power button
MADI card set at 48: M-1610 won't sync at all. Warning light appears on power button
MADI card set at 88.2: M-1610 will upsample to 96kHz and display a red flashing warning light on the power button
MADI card set at 96: M-1610 works as expected

But I would like to be able to have the M1610 auto switch to any sample rate between 44.1 and 96kHz without upsampling and without warning lights flashing, if poss.

I'm new to MADI (coming from AES), so any help greatfully received.

Douglas.

2 Reply by waedi (edited by waedi 2021-04-29 19:38:03)

  • waedi
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Re: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

Your requested auto-samplerate-following-feature is not to find in the user manual.
On page 55 is a table with configurations of samplerate settings and the resulting samplerate.
after all, the best you can do is select the same samplerate in every device.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • Max
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Re: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

see also: https://forum.rme-audio.de/viewtopic.php?id=32817

  • Registered: 2021-04-29
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Re: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

waedi wrote:

Your requested auto-samplerate-following-feature is not to find in the user manual.
On page 55 is a table with configurations of samplerate settings and the resulting samplerate.
after all, the best you can do is select the same samplerate in every device.

Yes, I have read the manual cover-to-cover. I am trying to determine whether I am doing something incorrectly. But, it seems I am not. Skimming through Max's link also, it seems like the short answer is that there is no way to have the M1610 auto-switch sample rate.

It seems like this is something to do with the AVB architecture, in which case I think it would be really useful to be able to run this unit in MADI only mode. At home, I am using MADI only. On location, I'm, using AVB only. When I'm at home, I'm often switching between projects and playing back content at different sample rates. So auto-switching would be very useful. On location, I am generally recording at a set sample rate, so no auto-switching is necessary.

But for now, the closest you can get to auto switching is is to set the M1610 to 48kHz slave mode. It will then play back any audio from 44.1kHz to 96kHz as follows: It will play back 48kHz and 96kHz correctly without warning lights. It will play back 44.1 (upsampled to 48kHz) and 88.2 (upsampled to 96kHz) with a warning light.

  • Max
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Re: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

dwhates wrote:

But for now, the closest you can get to auto switching is is to set the M1610 to 48kHz slave mode. It will then play back any audio from 44.1kHz to 96kHz as follows: It will play back 48kHz and 96kHz correctly without warning lights. It will play back 44.1 (upsampled to 48kHz) and 88.2 (upsampled to 96kHz) with a warning light.

There is no up- or downsampling for MADI in any of our products in 2021. You can use a 96 kHz word clock or a 96 kHz MADI signal with activated 96k frame to synchronize a device at 48 kHz (although that won't work with two or more devices reliably because they cannot tell which of the two possible rising edges the other device has locked to). That means, that the internal 48 kHz sampling rate would be phase-aligned with an incoming 96 kHz signal. But any audio that is sent across the single speed (44.1/48) / double speed (88.2/96) boundary will become distorted and unusable.

You have to at least set a sample rate in the same range, so either 44.1 kHz or 48 kHz work for 44.1 kHz and 48 kHz, and either 88.2 or 96 k work for incoming sample rates of 88.2 kHz and 96 kHz.

6 Reply by dwhates (edited by dwhates 2021-05-01 10:20:09)

  • Registered: 2021-04-29
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Re: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

Thanks for this info Max.

It seems I'm confused by the manual (p. 46), where it states MADI input with the clock set at 48kHz and a selected sample rate of 44.1 will result in a sample rate of "48kHz (with warning)". I had assumed this means it is upsampling. Is this not the case?

7 Reply by Marc S (edited by Marc S 2021-05-01 12:56:41)

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Re: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

No. The audio engine will adapt to the rate it detects from the input selected as clock source.

That means, if MADI is selected as Clock Master, and the incoming signal is 44.1 kHz, then the entire device will switch over to 44.1 kHz.
If you connect a scope to the word clock output, for example, you'll see an 44.1 kHz rectangle.

But due to the way AVB handles clocks and the resulting constraints, it will show you a warning, because you haven't explicitely set the sample rate to 44.1 kHz and the AVB stream's metadata is still set to 48 kHz.

A MADI only mode, or something comparable, is already on our roadmap for a future firmware release. But lengthy discussions already showed that there are a lot edge cases to consider. Give us a little more time here.

So, what does this mean at the moment:
f you don't use AVB, and clock to MADI or Word Clock, you can safely ignore the warning if your signal switches between 44.1 and 48 kHz.
Same for 88.2 and 96 kHz and for 176.4/192.
However, switching between single and double or quad speed (i.e. from 44.1/48 to 88.2/96 to 176.4/192) requires you to actively set at least the range.

8 Reply by dwhates (edited by dwhates 2021-05-02 19:35:47)

  • Registered: 2021-04-29
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Re: HDSPe MADI into M1610-Pro: auto samplerate switching possible?

Thanks for the explanation. So, the device is auto-switching, but the AVB stream/system won't have followed the switch and therefore may mismatch.

You say switching between single and double speed required the user to actively set at least the range, but that is not my experience. If I set my HDSPe MADI card as master (int), and I set the M1610 clock to to slave (syncing to the MADI card's output), then it simply follows whatever samplerate I have the MADI card at.

EDIT: although, the clock is for half the rate at the higher speeds, so, as you say, perhaps problematic when syncing more than one device to the unit.