Topic: Two R4's On The Same Clock? (8 channel mix)

[kcmule]

While I don't think this is possible, I figured I'd ask anyway.

Is it possible to get two R4's sync'd to the same clock?

Needing to take an 8 channel board feed, but would like to have
the same clock and not mess around with post alignment.

Thanks.

[Patrick]

This would only work on the R4 Pro or the R44, which both have word clock inputs and outputs.  Unfortunately the regular R4's don't have this feature.

[easy jim]

Well, the R-4 resamples the digital input (which would be the only way to lock to an external clock, if the digital worked as it ought to), so the short answer is no.  Two R-44 or 2 R-4 Pro units, or one of each, could be locked on to the same clock signal; but you would also have to make sure the two AES/EBU (R-4 Pro) and/or s/pdif coax (R-44) signals are also synced to each other.

To do this without sync issues, you're really going to need something other than an R-4...even with 2 R-44/R-4 Pro, you'd either need 2 external A>D devices (at least one of which must have the the ability to sync to the other) or a master clock device (for which, then, everything would have to be able to sync to an external clock signal - whether word clock, s/pdif, or AES/EBU).

[kcmule]

Thanks for the info Gents.

Soundman will have to mix a separate matrix of those 8 channels
and feed me a stereo mix on two channels.

[easy jim]

This would only work on the R4 Pro or the R44, which both have word clock inputs and outputs.  Unfortunately the regular R4's don't have this feature.

Actually, the R-4 Pro has timecode, but not word clock.  The digital sync possibility is AES/EBU for the R-4 Pro.

I've yet to hear that the 1/8" mini actually works as a word clock sync on the R-44, however, especially since 1/8" mini seems an odd way to send a word clock signal (typically sent on a BNC connector).  It seems to me that while it may be a way to effectively sync two R-44s, if it works as the promo materials claim, that the way to sync an R-44 with some other external device is via s/pdif.  Has anyone tested this yet?

[Patrick]

This would only work on the R4 Pro or the R44, which both have word clock inputs and outputs.  Unfortunately the regular R4's don't have this feature.

Actually, the R-4 Pro has timecode, but not word clock.  The digital sync possibility is AES/EBU for the R-4 Pro.

I've yet to hear that the 1/8" mini actually works as a word clock sync on the R-44, however, especially since 1/8" mini seems an odd way to send a word clock signal (typically sent on a BNC connector).  It seems to me that while it may be a way to effectively sync two R-44s, if it works as the promo materials claim, that the way to sync an R-44 with some other external device is via s/pdif.  Has anyone tested this yet?

This is correct, I was mistaken (didn't look up the facts and was going off of memory!)

The 1/8" jack on the R4 is actually just a control voltage that allows the R4 to sync up to a camera's starting/stopping times.  This has nothing to do with time code or a digital sync for another audio device.  This is how it was explained to me, and I've never used the jack despite having worked with several video guys.

[easy jim]

This would only work on the R4 Pro or the R44, which both have word clock inputs and outputs.  Unfortunately the regular R4's don't have this feature.

Actually, the R-4 Pro has timecode, but not word clock.  The digital sync possibility is AES/EBU for the R-4 Pro.

I've yet to hear that the 1/8" mini actually works as a word clock sync on the R-44, however, especially since 1/8" mini seems an odd way to send a word clock signal (typically sent on a BNC connector).  It seems to me that while it may be a way to effectively sync two R-44s, if it works as the promo materials claim, that the way to sync an R-44 with some other external device is via s/pdif.  Has anyone tested this yet?

This is correct, I was mistaken (didn't look up the facts and was going off of memory!)

The 1/8" jack on the R4 is actually just a control voltage that allows the R4 to sync up to a camera's starting/stopping times.  This has nothing to do with time code or a digital sync for another audio device.  This is how it was explained to me, and I've never used the jack despite having worked with several video guys.

Well, I think the R-44's promo material and manual claim that its 1/8" mini jack is actually a word clock sync (unlike the R-4) for linking two R-44s.  I'd still love to know if anyone has tested that yet.

[SmokinJoe]

In theory, you can't do it, but in practice you can do it in ways that will probably get you close enough that you won't be able to tell the difference.  You will have definitely have to align them left/right, but it shouldn't require any stretch/shrink.  If you have the R4's, I say go for it and make it work.

Just record to the two R4's and see if they line up.  I've taken sources from 2 UA-5's before and the clocks matched well enough that you didn't need to stretch/shrink either of them, just line them up.  In, fact I've seen this a few times with different UA-5's.  It's simply that the manufacturing tolerances on the clocks are "close enough".

If that isn't close enough try this:
- Take your 2 R4's you recorded to separately... arbitrarily call one of them the Master "A", and the other B.
- Take the files from A and copy to your computer.
- Set up a digi-patch from B to A, and dub real time from one to the other.  You will have to do this twice, once for channels 1/2, and once for channels 3/4
- Since the R4 resamples, even if the clock on B is different from A, it will resample it, and it should match what it was when it did the initial recordings on A.
- now take the new "dubbed files" from A and they should match with B time clock wise.
- What this really depends on is that the clock on B will play back at the same rate it recorded (which it should), and that A will record at the same rate twice in a row (which it should).

I have recorded Mics > R4, and SBD > R-09 before... when you pull up the two tracks they are off 300ms/hour.  So I patched R-09 > ODL276a > R4 and it was within 2ms/hour... close enough for me.

[kcmule]

Interesting.  I'll have to give this some more thought.