Topic: syncing 2 r-44s

[mepaca]

The following is from the r-44 FAQ section of the Roland website. It seems to conflict with the prevailing word
around here. If true it's good news.


 Q. How precise is the synchronization when two R-44s are connected via the CONTROL SYNC terminals?

A. When two R-44s are connected via the CONTROL SYNC terminals, they share the audio clock.
Therefore, delay due to time passing does not occur with recorded data.
In addition, the operation information is also sent, and start and stop operations are also synchronized. However, there is a time lag between two R-44s and the recording start time can slightly differ.

Reference:
The clock synchronization jitter is 1000ppm or less.
Difference of recording start time between two R-44s is approximately 10msec.
If pre-recording is set, the time lag becomes larger.
Because a time lag occurs with the recording star time as mentioned above, you need to use DAW or other tools to strictly align the phases after recording.

[runonce]

not sure what "the word" here is - but dont confuse the concept of clock sync with "start sync" (operation information)

I think - start sync is not as relevant(at least for taper pursuits)...since we can time shift the resulting track sets.

[mepaca]

It says "they share the audio clock". The prevailing word around here is that they don't. I am not confused.

[kirk97132]

You are right.  Edirol info on the website says yes they share the clocks and hence should not be drift.  My own real world experience contradicts that information*.  A phone call to Edirol tech support also gave me conflicting information in regards to the website.  Tech support said transports are synchronized but not the clocks.  I do not think there is any hard answer that can be absolutely confirmed in real world examples.  Some people have had no problems.  some people have had problems.

Then there is the other variable.  IF in fact the clocks DO NOT sync, you still could have two decks that run at the same speed or nearly at the same speed.  The closer the two speeds are the longer it will take before any drift becomes audible(or visible), so a shorter piece of music might not show any drift issues.   


* Second R-44 was a Busman modified unit.  I don't see how that could matter but it was a difference between the two identical decks.

[runonce]

Quick question - forgetting about the whole control sync thing...lets assume that has start/stop info only...

Can you use another digital feed as your clock? - and still run 4 A>D channels? (like, use one R44 as the master clock and slave the other to it - but disregarding the audio data in the master)

example - on my Behringer A/D converter - I can select "Internal, Dig-In, or External" as the clock source...

[page]

Quick question - forgetting about the whole control sync thing...lets assume that has start/stop info only...

Can you use another digital feed as your clock? - and still run 4 A>D channels? (like, use one R44 as the master clock and slave the other to it - but disregarding the audio data in the master)

example - on my Behringer A/D converter - I can select "Internal, Dig-In, or External" as the clock source...

yes. that was the idea I suggested to acidjack in the 680 thread.

[Ozpeter]

I thought the "they don't continuously sync" thing was laid to rest a few weeks ago, somewhere in the main R-44 thread.

[acidjack]

Quick question - forgetting about the whole control sync thing...lets assume that has start/stop info only...

Can you use another digital feed as your clock? - and still run 4 A>D channels? (like, use one R44 as the master clock and slave the other to it - but disregarding the audio data in the master)

example - on my Behringer A/D converter - I can select "Internal, Dig-In, or External" as the clock source...

yes. that was the idea I suggested to acidjack in the 680 thread.

...an idea I am anxious to try out. It is odd that Edirol seems to putting out info that contradicts real world experience.  I can attest for sure that there can be considerable clock drift between 2 R-44s, so you need something to get the clocks synced.

[DSatz]

I doubt very much that the control input is also a word clock input. If so, then the spec of "1000 parts per million" is ludicrously bad--that is 0.1%, or about the flutter rate of a good analog cassette recorder. Something is quite wrong here in any case.

--best regards

[kirk97132]

I can confirm acidjacks experience.  Two different R-44's with a sync cable had drift issues. 

As for clocking options via the menu, the R044 does not support anything beside a choice between analog and digital input on a pair of channels. 

The USBPre2 would allow the use of R-44(A) as a clock source then feed R-44(B) two channels analog & two channels digital.   R-44(A) could be 4 analog inputs or two analog & two digital if you had a second digital spdif coax source for it.


There has been a lot of discussion regarding this.  One side of the fence is Edirol says they sync and people who have had no sync issues.  The other side of the fence is the real world feedback that there is a sync issue.  While I am sure the people who have reported the decks to run in perfect sync are telling the truth it does not negate the fact that more than one person has had a drift issue.  So no matter what the manual says or what other people have experienced the facts are some people have not been able to get two R-44's to run in sync.

I do know that the USBPre2 can solve this problem since I use it exactly for this reason and have successfully synced two DR-680's with it.  Mr Satz did point out something that I had never taken into consideration.  That the error rate Edirol is posting is not very good.  I think if you want 6 or eight channels then the Tascam DR-680 is the most affordable choice(remember you need a preamp with digi output for channels 7 & 8 ).   IF all you have is two R-44's to use then maybe borrow a USBpre2 to insure the clocks are synced. That rig would allow 6 channels of analog input and two channels of digital input. 

[DSatz]

kirkd, I often record two digital and two analog channels on my R44; it certainly seems as if the A/D converters for channels 3 and 4 slave to the incoming frame rate of the S/P-DIF input (i.e. channels 1 and 2) when I do.

Given that, why wouldn't the two decks be "sunc" if you connected four analog inputs to the first R44 (or as I described, one pair of digital channels and one pair of analog), then connected its S/P-DIF output of the first deck to the S/P-DIF input of the second deck, along with two other analog sources connected to the second deck? That should give you six inputs on the same clock without the need for an external A/D, although you could certainly use one if you wanted.

--best regards

[page]

kirkd, I often record two digital and two analog channels on my R44; it certainly seems as if the A/D converters for channels 3 and 4 slave to the incoming frame rate of the S/P-DIF input (i.e. channels 1 and 2) when I do.

Given that, why wouldn't the two decks be "sunc" if you connected four analog inputs to the first R44 (or as I described, one pair of digital channels and one pair of analog), then connected its S/P-DIF output of the first deck to the S/P-DIF input of the second deck, along with two other analog sources connected to the second deck? That should give you six inputs on the same clock without the need for an external A/D, although you could certainly use one if you wanted.

--best regards

it does. If you're shooting for 8 unique channels though, you need an A/D unit in front of the second R44 that will accept 3 signals; 1 SPDIF or WC, and 2 analog while the unit passes along the 2 analog and clocks them against the digital signal (which in this example the usbpre2 accomplishes).

[RichT]

A while ago I got a minijack out to BNC and managed to get my RME multiface to sync with the R-44 on wordclock, and vice versa (after reading that FAQ on the Roland site). I haven't done this in the field though.

It's in the main R-44 thread from a while back: http://taperssection.com/index.php?topic=123284.msg1832480#msg1832480