• From: Oakland, California
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Topic: Choosing Clock Master with SteadyClock

My apologies if this has been fully addressed elsewhere.

Like many manufacturers of AD converters, Cranborne Audio's documentation for their 500ADAT ADAT expander strongly recommends using their device as the clock master in all cases (at least when recording).

Does SteadyClock functionality do away with applicability of that requirement/recommendation?

The relevant parts of my setup:

Mac <--USB--- MADIface USB <--MADI--- ADI-648 <--ADAT--- Cranborne 500ADAT (ADC)
Mac ---USB--> MADIface USB ---MADI--> ADI-648 ---ADAT--> Cranborne 500ADAT (DAC for inserts etc.)
Mac ---USB--> MADIface USB ---MADI--> ADI-648 ---ADAT--> ADI-2 Pro FS BE ---AES--> digital monitors

From a usability standpoint, I would prefer to have the MADIface serve as clock master with all other devices set to slave, so the sample rate of the entire system can be changed from within the DAW (or at least that will be possible when Cranborne updates their firmware).

Does the SteadyClock in the MADIface and the ADI-648 make that an acceptable solution?

Thank you,
Adam

  • vinark
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Re: Choosing Clock Master with SteadyClock

Short answer is no. If  Cranborne advises it to be clock master, it means their version of clocking is not so good, less good jitter reduction and PLL.. IOW it performs best as a master. With steadyclock by RME it is advertised it works just as good as slave as master, good jitter reduction and PLL etc.
Steadyclock can not cure jitter in the Cranbornes recordings of course.
But, if this has any audible implications is another question. If you can hear no difference between the  Cranborne as slave or master, I would go for the most practical solution.
If the question was the other way around, must my steadyclock equiped rme device be master? Then the answer would be no can be slave or master without issues.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632

3 Reply by ramses (edited by ramses 2021-12-28 07:45:58)

  • ramses
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Re: Choosing Clock Master with SteadyClock

EDITED

If you work with different sample rates, you probably won't enjoy having to adjust the DIP switches on the back of the 500ADAT over and over again.
Therefore I would consider to use the Digiface USB as clock master. Then you would automatically set the sample rate on all devices with the DAW project at single speed.
Maybe not at double speed, because then 2 ADAT channels are multiplexed.
I would try both and listen to the recordings.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

4 Reply by ramses (edited by ramses 2021-12-28 07:44:34)

  • ramses
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Re: Choosing Clock Master with SteadyClock

EDITED

P.S.: alternatively you could also use the ADI-2 Pro as clock master, then you have a FS clock as source.

If this is the ADI-2 Pro FS R BE with the remote, then you can use the remote and the remap key feature, to choose different configs with different clocks.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • From: Oakland, California
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Re: Choosing Clock Master with SteadyClock

Thanks, vinark. Here's what Cranborne say in their manual:

The facts and figures of 500ADAT’s built-in clock are good enough to stand up against - and in some ways exceed - the performance of what you would find in expensive standalone units. ... We employ converters with specifications that rival that of the best standalone units whilst being governed by our master reference-grade clock featuring less than 0.5 picoseconds of jitter.

and

When slaving 500ADAT from an external clock, its own internal clock syncs to the incoming timing information and recovers its own improved clock. For the best results and the highest quality conversion, we recommend using 500ADAT as the clock master of your studio.

and

If [the 500ADAT] is slaving from another source, the Word Clock Output passes through the recovery clock information to sync further downstream equipment.

So that makes me think it's actually both a decent clock source and, more importantly, if it's set to slave, it recovers/generates its own clock well based on what it receives from the master clock. I don't have enough information to tell how that compares to SteadyClock, however--I wonder if they're just trying to head off user support inquiries when slaved to an inferior clock source (which presumably would not include any of the RME interfaces)?

  • From: Oakland, California
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Re: Choosing Clock Master with SteadyClock

Sounds like I will really just need to compare with my ears--thank you, vinark and ramses!

  • vinark
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Re: Choosing Clock Master with SteadyClock

It is as they say, for best AD conversion set to clock master. Thats all. How much inferior as slave is not dependent on what clock you feed it alone. Clock recovery from a external clock is a complicated process with compromises like speed of locking vs jitter, what if one clock is missed, dropouts vs jitter etc. The very best converters and I mean expensive perform (almost ) identical as slave or master, like with RME steadyclock FS. But if a manufacturer advices master while recording and the recording is top critical I would listen. But nothing I do is that critical lol that is up to you.
It it is not just the clock you feed it but also the connectors and cables and you can't listen or easily measure a 75ohm cable if it is functioning correctly. This all said, I never worry and do what is pctical, but my main work is in the box, limited recording only, so my DA is most important.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • ramses
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Re: Choosing Clock Master with SteadyClock

In a perfect world we would measure it like MC does wink

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • vinark
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Re: Choosing Clock Master with SteadyClock

ramses wrote:

In a perfect world we would measure it like MC does wink

And become even more obsessed and disturbed. Clock perfect, the new bit perfect lol.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632

10 Reply by ramses (edited by ramses 2021-12-28 08:29:24)

  • ramses
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Re: Choosing Clock Master with SteadyClock

yup, ClockPerfect(TM) by vinark lol

BTW .. I also read about the comment in the 500ADAT quickstart manual to mute the ADAT channels of the recording interfaces during clock synchronization because of noise ...

Maybe best to try all combinations to look what works best and also in single/double speed.

And the next lunchbox is one with analog outputs ? ;-)) Sorry, just kidding :-)

I am convinced, that you will find a good solution and that all combinations are not bad or different sounding in any way.

But I recommend to perform also blind tests when checking the sound with the help of a 2nd person, otherwise you could too easily be biased.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • vinark
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Re: Choosing Clock Master with SteadyClock

I agree Ramses, I would be highly surprised if anything was audibly different in a blind test.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632

12 Reply by ramses (edited by ramses 2021-12-28 08:32:46)

  • ramses
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Re: Choosing Clock Master with SteadyClock

BTW .. what do use for sound checks ? I use songs of good quality with a good mix that I know. Some examples:

Cassandra Wilson - Resurrection Blues (Tutu) - sound: acoustic bass, guitars, separation of instruments, vocals
Dave Weckl Band - What it is - nice slapped bass and good drums
Dean Brown - Big Foot - for bass, drums
Diana Krall - All or Nothing at all - where the voice is really excellent in front of you in the room.
Peter Gabriel - This is the picture - location of vocals
Phil Upchurch - Love is Strange - Effects Moving from L to R and vice versa / room
Presuntos Implicados - Tu tierra y mis semillas - good recording, vocals, etc
Rolf Kühn - Cucu Ears - very rich sounding and detailed, sound effects, many instruments
Steely Dan - Jack of speed and others - Quality

Of course I do not listen to them in a row .. but in each song you find something nice for A/B testing.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • From: Oakland, California
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Re: Choosing Clock Master with SteadyClock

ramses wrote:

And the next lunchbox is one with analog outputs ? ;-)) Sorry, just kidding :-)

Actually, that is a great point: all of the slots on the Cranborne also have parallel XLR outs, which means for the absolute BEST analog-to-digital conversion, I can patch the output of any two of the modules--or alternatively the 500ADAT's analog mix bus--directly into the ADI-2 Pro FS R BE's analog inputs. And then the clocking of the Cranborne doesn't matter at all. :-)

Thank you as well for the tips on A/B testing! A couple other favorite recordings for testing are Gary Burton's "Libertango" (stereo field placement and the resonance in the timbre of the vibes) and Avishai Cohen's "Colors" (especially the crispness/transients of the bass).