2x MTRX and HDX out of sync

[BScout]

Originally Posted by oortone

See attached screenshot.

I have some more info:

>What SFP's are you using?
>I would in the first instance look at those and the physical cabling.
>
Madi SC-sfp
They tried switching SFP's and cable connections but problem remained the same, did not move with SFP's or cables.

"What SFP" is asking what actual transceiver are you using (make/model). SFP = "small factor pluggable." It's the actual units plugged into the system. The question isn't what's connected to it (which you've given: MADI which is a protocol and SC = "subscriber connector" which defines the size of the fibre optic cable termination.)
Knowing the make/model gives info on the speed bandwidth (Mbits, Gbits, etc) and transmission signal (1300nm, 800nm, etc.) and type of transmitter. Furthermore, knowing the SFP transceiver can diagnose what type of cable needs to be connected (not just end termination like SC but mutli-mode vs single-mode and fibre diameters.)

[uptheoctave]

Originally Posted by oortone

See attached screenshot.

I have some more info:

>What SFP's are you using?
>I would in the first instance look at those and the physical cabling.
>
Madi SC-sfp
They tried switching SFP's and cable connections but problem remained the same, did not move with SFP's or cables.

>I might also try syncing over Dante as a test.
>Or using wordclock.
>
Wordclock cables are not available between these devices. Dante sync would be interesting to test next time.

This is why I said temporarily move the remote MTRX closer.
Just to see if it is related to distance.

Also, if you are using the MADI daughterboard then it might be worth trying DADlink.
You need gigabit SFP's for that though.

I find sync with multiple DAD/MTRX devices to be most reliable with wordclock, but my cable runs are under 1m, not hundreds of metres.

You may find Dante better though.

[oortone]

Originally Posted by uptheoctave

...
I find sync with multiple DAD/MTRX devices to be most reliable with wordclock, but my cable runs are under 1m, not hundreds of metres.
...

"Most reliable" you write, under which circumstances did you get issues?

...

In the case originally described, the current theory is that the cause was Dante traffic (from MTRX) and EuCon in the same unmanaged switch. Not that there's a really good explanation why but it seems to be improved now that they installed a managed Cisco switch and use fixed IP-addresses.

Although there has not been a big recording production in the venue yet after the new installation, so it's hard to tell for sure. Myself, I've no time for this right now unfortunately.

[oortone]

Originally Posted by BScout

Digilink has no "clock". In Pro Tools HDX, the hardware attached is the clock. Digilink only provides the sample rate. (You have to think of sample rate as a defined number not the actual pulse/synchonization signal.)
So Internal means the MTRX runs on its own crystal for the clock. The "Adapt to" setting of Digilink means that Internal crystal follows what sample rate it should be at from what Digilink is telling it should be at. But that Digilink info isn't an actual clock (pulse reference)
For the reason I mentioned above. Digilink isn't a clock. It is sample rate information only. All the other options for Sync Source are actual clocks (they have a synchronization reference)

Put it this way, you can't clock anything to an HDX card. Even with HD IO or HD MADI or Sync HD (or Sync X), the actual clock comes from the attached hardware (without the SyncHD, SyncX, loopsync makes one of the attached hardware the sample-rate clock for multiple pieces of hardware and it is designated as the loop master.) Pro Tools (the software) through the HDX card tells the hardware what sample rate it needs to be (like the control panel for most normal audio interfaces.) But the actual clock is coming from the hardware. Same true for the MTRX hardware.

Thanks, good to have this clarified.