External Word Clock

[Old School]

Hi All,
Well I received everything but the termination device and You were right, the behringer unit is not terminated. I will have to wait for the terminator before I can let you know how well (or not) this setup works.

Have a blessed day,
Mike

[Old School]

Hi All,
Still no joy. I received the termination device, but when I installed it on a tee at the ADA8200, and connected it to a tee on the HDR (with termination out on the HDR) and from that tee too the D8B, neither the HDR or the D8B receive any clock signal. The HDR and the D8B are set to external clock source. The red clock sync light on the HDR is flashing (which I assume means no WC signal and the D8B is flashing * ? . I tried removing the termination device and also tried changing the HDR to "terminated" but still nothing. I tried connecting the D8B to the HDR's word clock output instead of the tee, with the HDR still set to external and the D8B indicated it was receiving WC. Everything seemed to pass audio OK with no clicks and pops but the HDR's sync light is still flashing so I think that the D8B is really just receiving WC from the HDR's internal clock. Ideas anyone?

Have a blessed day,
Mike

[Y-my-R]

Do the Sample Rate settings match everywhere?

Here's how I'd go about troubleshooting (this is not for the full setup, yet - just to check what works and what doesn't):

A:
1. Set the Behringer to "Master" and the sample rate you want to use (let's say 44.1kHz) and connect a BNC cable directly to the BNC on the Behringer.
2. Connect the other end of the BNC cable directly to the BNC word clock input on the Apogee clock card in the D8B. Set the D8B to 44.1 kHz as well, and to sync to external clock.

What happens? Does the D8B lock to the signal? If yes, then you know that the Behringer is outputting a valid clock signal and may not need to be terminated (but it might still work, even with missing termination... just not as reliable, so it's better to figure that out).

B:
Regardless of the results, I'd try the same setup again, but this time with a T-Piece and the terminator on the Behringer end. Does this improve anything or do things stay the same?

C:
Now try the same thing again, but with the Behringer and the HDR. Like this:
1. Set the Behringer to "Master" and the sample rate you want to use (let's say 44.1kHz) and connect a BNC cable directly to the BNC on the Behringer.
2. Connect the other end of the BNC cable directly to the BNC word clock input on the HDR and push the termination button to the "in/pressed" position. Set the HDR to 44.1 kHz and to sync to external clock (...not to be confused with setting it to sync to SMPTE/MTC via MIDI - that's not directly related!).

What's the result? Does the HDR lock to this? If not, try again with the terminator added to the Behringer end. Does this work better?

If both of these tests fail, and you're 100% certain that the Word Block Master/Slave and Sample Rate settings were all correct, then the problem is likely introduced by the Behringer.

Is the Behringer connected to a computer/host, or are you trying to use it standalone?
From my understanding, these units "should" work standalone, but I think it may be necessary to do the setup at least one time via a computer. I never had one of these Behringer units, but at least for some other similar devices (e.g. M-Audio Profire 2626 and 610 or the Focusrite Pro 24 DSP I use standalone as a headphone amp synced to WC via S/PDIF), the "standalone" settings are separate from the settings when used via a host-computer, and the standalone settings still have to be made via a computer, before such a device is ready to be used standalone.
Might be similar for the Behringer (but I wouldn't know). Hopefully it's just the switch on the back, though.

If either the HDR or the D8B DO sync to the clock coming in from the Behringer in one (or more) of the above mentioned scenarios, then you know which device is introducing the problem (the one that doesn't want to sync) - then you know where to focus your troubleshooting efforts (likely settings or termination), before trying again.

You can, also try to word-clock sync the D8B and HDR directly (setting one of them to Master and the other to Slave, and connecting the BNC cables accordingly (ALWAYS directly to the BNC on the Apogee card in the D8B) and pressing the termination switch on the HDR in... but try it in the out position, too... just in case), to make sure those two devices still work together as they should - once again, to isolate the device which is causing the problem. (If that works, it would point to the Behringer, again).

I'd try all of this first, and share the results of the tests, here. Depending on which combination works and which doesn't, this could open more avenues to potentially use a different device than the Behringer as the Clock Master (D8B or HDR). In general, it's usually best practice to use the device as the clock master that you use for the A-to-D conversion (unless you use a Master Clock... but even then, it's often advisable to use the converter unit as the clock master, anyway. There's a good shootout test on the topic online, somewhere, that explains why... I'll try to find it and post a link, if I do).

Also... don't confuse SMPTE or MTC sync with Word Clock sync. That's separate and not directly related. IIRC, a blinking red LED on the HDR means that it's waiting for SMPTE/MTC sync.
I don't recall off hand if there's an LED for Word Clock sync, or if it only shows on the display if no word-clock sync is coming in (it might... not in front of it right now).
So, definitely double-check the settings on the HDR... from my recollection, a blinking LED in the front could indicate that it's set to sync to external SMPTE/MTC and isn't getting that sort of signal via the MIDI port.

Anyway... please post the results of what happens when trying to sync only two of the devices together (...especially with the Behringer as the clock master). Then, once we know where the failure happens, we can try different combinations to further isolate and identify the problem.

Also, if the sample rate matches between the devices, but the Word Clock Master/Slave settings and/or the termination isn't right, you may not immediately experience clearly audible clicks in the signal. But you'll likely hear a click at least every few minutes. But this doesn't mean that your signal is "clean" - there'd still be tons of jitter going on that may not immediately be noticable because each "word" of the word-clock sync doesn't line up exactly with the other device(s). Resulting in uneven "square waves" for the sync signal until they drift far enough apart to cause a click (again... could take a few minutes, sometimes). So, don't assume it's OK, just because you don't hear artifacts immediately. Your mixes will definitely sound worse in the end, with less depth on potentially some harsh overtones b/c of the sync/quantization issues of the clock if not properly synced together.

Best of luck!

[Y-my-R]

I think this is the article I meant, that explains word clock sync... but there might have been another one that was focussing more on AD/DA converters/audio-interfaces.

The concepts to understand about word clock and how the "square waves" that represent each clock pulse degrade, still apply - regardless of using a Master Clock, or clocking off of an audio interface or AD-converter.

https://www.soundonsound.com/techniques/does-your-studio-need-digital-master-clock

[doktor1360]

Hi All,
Still no joy. I received the termination device, but when I installed it on a tee at the ADA8200, and connected it to a tee on the HDR (with termination out on the HDR) and from that tee too the D8B, neither the HDR or the D8B receive any clock signal. The HDR and the D8B are set to external clock source. The red clock sync light on the HDR is flashing (which I assume means no WC signal and the D8B is flashing * ? . I tried removing the termination device and also tried changing the HDR to "terminated" but still nothing. I tried connecting the D8B to the HDR's word clock output instead of the tee, with the HDR still set to external and the D8B indicated it was receiving WC. Everything seemed to pass audio OK with no clicks and pops but the HDR's sync light is still flashing so I think that the D8B is really just receiving WC from the HDR's internal clock. Ideas anyone?

Have a blessed day,
Mike

Hey Mike... if I'm reading this correctly (which may not be the case), it appears the connections are a bit ass backwards... IF you're using the ADA8200 as the SOURCE. Should that be the case, and you're slaving the D8B and HDR from this clock, run a 75 ohm coax cable only OUT of the ADA8200 to the T-Connector on HDR (as it is and appears, unterminated), from there run another cable to a T-Connector on the D8B and use the terminator on that end. That should terminate the line properly - you'd want the last device on source clock being terminated. Another point with 75 ohm coax cables is to try to keep them the same length if you can - it's NOT a Show Stopper but oddly it may matter if you're experiencing trouble.

ADA8200 WC out -> HDR (t-connect, unterminated) in -> D8B clock card input (t-connect terminated)

That should do it, again, if I'm reading this correctly...

Of course, you absolutely knew it was coming so here it is:
[Standard Mgmt Disclaimer] - "Your actual mileage may vary..."

Post back if you test this method with the results...

\m/

[Y-my-R]

That's what we've been discussing, except for that you'd double-terminate, if you'd add a terminator on the D8B end.

The Apogee card is ALWAYS internally terminated, unless modified.

See here:
https://www.sonido-7.com/d8b/wordclock.html

...and if you read that article I linked to, you'll also find why it usually makes the most sense to clock off of the A-to-D converter you're planning to use (...they even tried another Behringer unit and even for that one, the clock quality was better if clocked off the Behringer, than off of an external clock going into the Behringer, b/c the external clock recovery is usually not that great... unless you're using a high-end device like that Metric Halo unit mentioned in that article).

So, exactly what you said, except for that adding a terminator on the D8B end is wrong.

...and the reason why Mike tried a t-piece at the source (Behringer) is b/c it didn't work when trying WITHOUT a terminator on that end. And from my experience, about half the devices that SHOULD be internally terminated, aren't. (But at least that always allows to ADD a terminator, while it's tricky to REMOVE termination, as is evident in that Apogee Clock Card mod article).

So, both ends of the chain need to be properly terminated, and the HDR should not be, if in the middle. So, don't add anything to the D8B, since it is ALWAYS internally terminated. And if a t-piece and terminator is needed on the Behringer end, depends on if it is internally terminated or not. So, try, and see what gives the best results (or results that are at least working).

About the cable lengths... that's usually about reflections going back into the cable... and that gets worse if not terminated properly... anyway... don't want to add confusion to this, so I better stop.

[Y-my-R]

Re-reading this again, though... I'm almost convinced now, that the HDR wasn't set to clock off of incoming word clock, but was running on internal clock, and was only blinking b/c it was set to sync to external SMPTE/MTC.

So, two clock sources going into the BNC cables (Behringer and HDR) will, of course, spell trouble.

My bet is on the HDR clock source still being set to internal instead of external, and that there's some confusion about Word Clock sync vs. SMPTE/MTC sync.

[Old School]

Hi All,
Sorry it took me so long to post back, but I was really sick yesterday, but feeling much better this morning. Anyway first let me assure you that I had my HDR set to "External" and am not confusing it with the SMPTE or MTC clock settings. Here is what I tried per your advice. I connected a BNC cable to the ADA8200 (no terminator) with the ADA8200 set to 48K Master and connected it directly to the D8B with the D8B set to "external". The D8B still flashed */? so no clock signal. I repeated this test with a tee on the behringer end with a terminator attached. The D8B still flashed */? so no clock signal.
I repeated these tests in the same manner with the HDR and the HDR sync light still flashes. This light stays solid red under normal circumstances even when the D8B is off (so no midi) so I don't think this light indicates SMPTE lock. I can only conclude that this unit is defective and not producing a valid clock signal since the HDR and D8B have no problems accepting word clock from each other. Do you agree or am I missing something?

[Y-my-R]

Sorry to hear you were sick - I hope you're already fully recovered, or will shortly! And about delays... doesn't bother me at all. We're not on the clock, here (no pun intended... or is it?)

Sorry about the assumption about the HDR not being set to external sync for word clock. I should know that you know better, after using these devices for all these years. Sorry again!

I just looked at a pic of the rear panel of an ADA8200... and it doesn't have any "Host" connection for configuration via a computer. I thought it did, but it's really just a standalone converter.

Did you try the same word clock cables when testing the sync between the D8B and the HDR? There's always a potential that one of those is bad. And you did use 75 Ohm BNC cables for this, right? (There are also 110 Ohm variants that could cause issues in this application).

If the cable(s) work in a different configuration, then yeah, maybe the clock inside the Behringer went bad.
Just for the sake of it, I'd try if the Behringer can successfully clock to an external clock signal when set to "Slave" at the matching sample rate generated by either the D8B or HDR, for this test.

Also, if you happen to have another computer audio interface or other device that can lock to incoming clock from the Behringer's ADAT optical output ports, that would also be worth a try.
The D8B can't lock via ADAT optical, and I *think* the HDR can't either. But most other devices with ADAT optical ports usually can - at least computer audio interfaces usually do.

So, if you have such a device available, I'd try if the Behringer works as clock Master and having a computer audio interface set to sync to it as slave, from the ADAT port. This way, you could verify if the clock on the Behringer is "really" bad - if other "ADAT sync capable" devices still lock to that signal, then the clock in the Behringer should generally still work, and it might be a contact issue, somewhere on the path to the BNC (or with the BNC itself or the switch for it).

Did you get that Behringer used? If you can still return, I'd try that. If you can't, then I'd try some contact cleaner in the Master/Slave switch, first.

I guess if everything else fails, you could still use the Pres in the Behringer (are they any good? "Midas designed" it says... but who knows if that's just use of the branding, after Behringer swallowed that company) and go out the XLRs in the back and to analog line ins on the D8B... but that defeats the whole point of going straight to the HDR via digital, as you had originally planned, to bypass issues you had with the analog signal path in the D8B.

[Old School]

Hi,
The behringer works fine in slave mode. The mic pres are clean, clear, and strong, with a very low noise floor, which is the main thing I was wanting from this unit as the D8B pres were never great to begin with and are now noisy and distorting a little. But I was really hoping to use the superior WC in the behringer to clock everything as it has been reported to be very good. But for now I can send the Optical output to my Aux in and still be able to monitor the output as well as route them to tape. Too bad the D8B doesn't allow for more than 8 auxillary inputs, then I could completely bypass all the D8B mic pre's. But for now, I think I'll keep it unless the guy I bought it from on reverb wants to give me a full refund.

Thanks for your help and have a blessed day,
Mike