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  #1  
Old 05-15-2014, 11:23 PM
MixerGuy MixerGuy is offline
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Default Loop Sync vs external word clock in.... all HDio interfaces

Loop Sync vs external word clock in.... all HDio interfaces

so I am changing my setup to be:
HDX-2
4 x HDio interfaces (various flavors)

all my digital reverbs just clock off AES from the interfaces
I NEVER need to run vary-speed
i NEVER need to lock to black burst.

so my options are:
Loop Sync with all 4 HDio interfaces….

or

word clock out of the first HDio interface, to a Word Clock distributor (that I already own)…. to the other 3 HDio interfaces.

The advantage of using word clock out of the first HDio interface, to a Word Clock distributor (that I already own)…. to the other 3 HDio interfaces….. is that days when I only need the first 2 interfaces… I can just leave the third and four interfaces off, so I get 50% less fan noise (I am in a 1 room facility)

I did do some searching and googling… could not find strong reasons to use Loop Sync over option b (word clock in on interfaces 2, 3,4)

anything I should know?

thanks
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Old 05-15-2014, 11:31 PM
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

Loop sync if all you need is put some Avid/Digidesign interfaces together.

I don't think it matters whether the boxes are on or off, loop sync gets copied from input to output passively, only active box is the loop master which is always on, and it checks whether the clocking has drifted along the way when the signal comes back to the master box.
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Old 05-15-2014, 11:33 PM
MixerGuy MixerGuy is offline
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

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Originally Posted by JFreak View Post
Loop sync if all you need is put some Avid/Digidesign interfaces together.

I don't think it matters whether the boxes are on or off, loop sync gets copied from input to output passively, only active box is the loop master which is always on, and it checks whether the clocking has drifted along the way when the signal comes back to the master box.
really?

wow.

I'm shocked. I would think that an interface (or 2) being off would mess up Loop Sync.

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Old 05-15-2014, 11:34 PM
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

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anything I should know?
The secret of loop sync always being base sample rate (44.1k or 48k) no matter whether you are using higher sampling rate or legacy gear (256x clock).

In those cases, if you need to feed base clock to some other box that does not accept 256x superclock or won't lock to 96k clock, you can just insert a passive t-splitter to the loop sync and feed the base clock to the box from there.
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Old 05-15-2014, 11:36 PM
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

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I'm shocked. I would think that an interface (or 2) being off would mess up Loop Sync.
Test it. If it doesn't work like I described, you will get instant pops and clicks just the same way if you removed one cable from the sync loop. Test that too and see what happens and when you have a broken cable some day you already know what's wrong.

Don't believe anyone, test it by yourself.
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Old 05-15-2014, 11:47 PM
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

Btw, here is the old white paper from Digidesign 192 clocking. It's a good read when you decide whether or not you should or shouldn't buy external master clock.

It does not say that Avid/Digidesign interfaces can be turned off, but it does say that loop sync is better if you don't need anything else besides putting interfaces together.
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Old 05-16-2014, 06:56 AM
MixerGuy MixerGuy is offline
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

thanks for all the good replies.... seems like Loop Sync would be best....

if the fan noise is manageable with all 4 interfaces on.... should i just keep all 4 on, at all times?

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Old 05-16-2014, 01:19 PM
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

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thanks for all the good replies.... seems like Loop Sync would be best....

if the fan noise is manageable with all 4 interfaces on.... should i just keep all 4 on, at all times?

If it's manageable, then it is. And loop sync is always the preferred option, you need to have a real reason to not do it...
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Old 05-16-2014, 03:02 PM
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

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If it's manageable, then it is. And loop sync is always the preferred option, you need to have a real reason to not do it...
Cool.

But just curious - what is the technical reason that loop sync is better ?
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Old 05-16-2014, 10:45 PM
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Default Re: Loop Sync vs external word clock in.... all HDio interfaces

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But just curious - what is the technical reason that loop sync is better ?
It's explained in the old white paper, read it if you want to know. I can only summarize that it is better.
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