1 Topic by uptildawn (edited by uptildawn 2023-05-10 21:27:50)

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Topic: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

I am testing ADAT Sync between a pair of Digiface/pcie and 3 Midas DL16 Stageboxes.
I have assigned the 2 adat output pairs of each dl16 (ch 1-8 and ch 9-16 on each unit for a total of 48 channels) to the pair of Digifaces - with the 2nd dl16 split between the 1st and 2nd Digiface units).  The 2 Digifaces are sync'd with WC.

So far, I've been able to test record a single microphone source split at the physical inputs to channel one of all 3 DL16s for upwards of 1.5 hours, (apparently) without any drift whatsoever.  However, I am seeing at least one adat channel light of each Digiface blink on/off on a regular basis (roughly 20-26 second intervals) and this has me concerned.

I've never relied on adat to sync multiple preamps before - always having used word clock.  But I have to, since the Midas has no wc and only adat out (no adat in).  Can someone tell me/assure me if this is normal behavior when syncing via adat?

Is there some other way I should be hooking this all up to be assured of sync for hour to 2 hour long recordings of upwards of 48 tracks in a live concert setting?  These Midas units are replacing my 16-20 year old Presonus preamps and I can't afford to invest another 2-3k replacing the pcie interfaces as well at this time.

2 Reply by waedi (edited by waedi 2023-05-10 23:04:39)

  • waedi
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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

Blinking Led means sync problem.
It is locking but no sync.

In the Hammerfall DSP settings have you select clock-source external adat optical ?

What does that mean, "The 2 Digifaces are sync'd with WC" ?
from where ? You say the Midas have no Wordclock.
The Digiface where you connect the adat from the Midas have to be be set to clock-source external adat.
Then the other Digiface clock-source may be Wordclock, assuming both Digiface have Wordclock board and are connected.
As the Midas has only Adat out, it must be master clock.
Probably you can only record one Midas at a time.
With the two Digiface you can have two indipendent recording systems on two computers. Then recording of two Midas is possible.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

Thanks for your reply...

The 2 Digifaces are sync'd via word clock physically, using the wc bnc connectors on the digiface boxes (this is as I've always done in the past as well).  Hammerfall DSP clock source for card 1 is set to adat 3 (Midas #2 box ch 1-8) .

SyncCheck (card 1) shows wc and adat 3 (Midas #2 box - ch1-8) in constant sync, while adat 1 and 2 (Midas #1 box ch1-8 & 9-16) switch every 20 seconds or so to Locked and then back to Sync within a second or two.

DSP clock source for card 2 is set to adat - Time Code shows Card 1 (expected, since the two are physically coonected by a wc loop).
SyncCheck (card 2) shows wc and adat 1 (Midas #2 box - ch9-16) in constant sync, while adat 2 and 3 (Midas #3 box ch1-8 & 9-16) switch every 60 seconds or so to Locked and then back to Sync within a couple of seconds.

Although I fully expected at the start that I might/would experience drift between the audio tracks at the very least - and probably random clicks and pops (as I had in the past with a bad wc cable), I'm very surprised to not having any of that so far.  In fact, I can actually cancel the 3 tracks in null-tests and the tracks are sample accurate across the entire 1.5 hours (checked randomly down the timeline).

This is why I'm reaching out and thankful for your quick reply, even if it isn't reassuring - at least it has me triple-checking everything and considering every possible option I may have to make sure what I end up with will be reliable in the field... even if I am forced to reinstate my roadweary Presonus preamps in the end.

Any further details and suggestions are more than welcome!

4 Reply by MC

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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

In such a spread setup there are varying phase shifts between the ADAT signals (and clocks). If these exceed a certain amount the DF will signal Lock. We have seen such large deviations also with Yamaha and adapted our Lock indication threshold a bit on later products. The fact that your recordings are completely error free point to this effect here.

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Matthias Carstens
RME

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5 Reply by vinark (edited by vinark 2023-05-11 06:57:32)

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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

I don't know the midas boxes but how are those 3 synced. If they are in sync it should also work without WC.

Vincent, Amsterdam
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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

MC wrote:

In such a spread setup there are varying phase shifts between the ADAT signals (and clocks). If these exceed a certain amount the DF will signal Lock. We have seen such large deviations also with Yamaha and adapted our Lock indication threshold a bit on later products. The fact that your recordings are completely error free point to this effect here.


Whatever you've done, RME has just reconfirmed my great confidence and appreciation for the highest quality and dedication to maintaining the highest standards you all provide to users - even for products 20 years old (and more).

I just recorded 5 microphones of a single source, across 48 tracks, for 2.5 hours straight and had not so much as a single glitch and no drift.

Interestingly, when I asked a guy at Midas a few days ago what I might expect (after having tested just 2 units and a couple of 10 minute recordings and noticing the lights flickering), he replied that he anticipated that the 3 units would play nice and stay in sync - just as they have.  I can't help but feel as though most (if not all) the credit goes to RME's designs.... Amazing!

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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

vinark wrote:

I don't know the midas boxes but how are those 3 synced. If they are in sync it should also work without WC.


I can't even begin to say that I understand how they stay in sync, especially after years of reading/hearing how easily adat can be messed up, especially when compared to wc.  Maybe I will test the idea of yours tomorrow, just to find out if they keep sync with the wc cables removed.

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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

I had a look and it seems they are not synced. So then it is best to keep the 2 RME with wc and in sync. It is indeed great work of RME but also midas that 3 devices run that closely in sync without actual sync as I understand it and not cause major problems

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

Yes, it's absolutely great work of both Midas and RME.
I'm still baffled by the consistent sync of the tests I've run so far - another 2.5 hr test last night was without incident.
Still testing though...

  • Registered: 2009-03-01
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Re: ADAT Sync ? with 2x Digiface & 3x Midas DL16 Stageboxes

MC wrote:

In such a spread setup there are varying phase shifts between the ADAT signals (and clocks). If these exceed a certain amount the DF will signal Lock. We have seen such large deviations also with Yamaha and adapted our Lock indication threshold a bit on later products. The fact that your recordings are completely error free point to this effect here.

Matthias,
Would you clarify this comment for me?
Are you saying that i can trust the glitch-free evidence of my test recordings over the flashing sync lights on the Digiface boxes?
Or should i be going back to the Presonus preamps sync'd with wc that i used to use?

Thanks for your help.  You've always been very helpful and i appreciate it.