Clock/Loop Sync Advice, Please...

[danbozek]

Hello. I hope this is the correct forum to ask this question. Moderators, point me elsewhere if I'm dumb. Ha ha ha.

I'm reorganizing some gear for a rig and I keep getting -9xxx errors. I have a Rosetta 800, two 192s, and some old Presonus light pipe unit that I'm using for overflow musician listen-back mics, etc... I have the BNC clock out of the Rosetta into 192 A, the BNC clock out of A into B, the BNC clock out of B into Presonus. This works—EXT lights on the 192s are lit and also on the Presonus, and it sounds great. Bu the persistent error messages conspicuously mentioning clock make me think I should be doing something better...

What am I missing? Admittedly, I don't remember the significance of Loop Sync vs. external (except that it needs to be a closed loop.) Help a brother out!!

[JFreak]

First you need to connect the 192's together via Loop Sync, that is a must. Then you connect ext.clock to external (non digidesign/avid) boxes.

[danbozek]

Do you think it would be advantage to pick up an old Sync for this gear? Will that simplify and or make things better? They’re pretty easily and inexpensively available.

[JFreak]

It will not simplify anything, on the contrary really. Start with connecting 192's to Loop Sync, test that it works, then add one box at a time.

You only get a problem if both your external boxes are word clock output only (as in ADAT connection without wordclock i/o), which means they both need to be clock masters and there can only be one clock master in your clocking chain. But that is exactly the same situation with distributed clock.

Lucky I have one of those Apogee Rosetta 800's with X-HD card so I know for a fact that it can be slaved to 192's clock signal (from ext.clock not loop sync), but whether your Presonus has wordclock input or not I have no idea. If it does not, your only option is setting it clock master, then what happens you need to let 192's slave to external clock.

[Top Jimmy]

It is possible to have a small amount of phase shift between the clock in and clock out on a piece of gear. Passing clock serially in this manner can mean that the last piece of gear in the chain can have just enough phase shift to cause a problem when attempting to pass data back to the first device.

Distributing word clock should always follow the star distribution method for best results.

As Janne pointed out, the 192s would work best in loop sync. Personally, I would make the first 192 the clock master syncing the Rosetta and the Presonus via word clock. If either the Rosetta or the Presonus has an unterminated word clock input, you could use a BNC T to split the word clock with the terminated input at the end of the line.

[JFreak]

In this case, with two loop synced 192's better way would be connecting Apogee from first 192 wc out and Presonus from second 192 wc out, assuming the presonus box has wc input. Rosetta has, it is not a problem.


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[danbozek]

Originally Posted by JFreak

In this case, with two loop synced 192's better way would be connecting Apogee from first 192 wc out and Presonus from second 192 wc out, assuming the presonus box has wc input. Rosetta has, it is not a problem.

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Yes, this seems to make the most sense to me. The Presonus has wc input. I'll try this later today when I get back to the studio.

Is there a better from-this-era-ish used price-range unit that would be a better master clock sonically for the entire rig than a 192? Maybe a used Big Ben or a Lucid or something like that? I don't have a lot of $$$ to further expand this rig at the moment, but I could do something used if it would make a big difference.