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Author Topic: Digital Clock Sync  (Read 2246 times)

tuchel

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Digital Clock Sync
« on: May 10, 2005, 04:46:46 PM »

After searching around on this topic, I'm hoping someone might shed some light on a few questions regarding use of am external master clock.

1- On a small set up such as mine (Digi 888/24, Rosetta, AudioMedia II card) is there a significant benefit gained when using an external clock?

2- Since a clock syncs different gear together, do some units do this better than others, and if so, how can that be?

3- I have a seperate computer that handles sampling playback using the SPDIF digital out of an (digidesign) audiomedia card, does this need to be clocked together with the rest, and can I do this by sending the clock signal into the digital in?

Thanks;

Terry Sampson
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PaulyD

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Re: Digital Clock Sync
« Reply #1 on: May 11, 2005, 11:36:07 PM »

I think the only way to find out is to rent a clock device and do some listening tests. You can read what Michael Cooper said about the effect of slaving a MOTU HD192 to an Apogee Big Ben. There is a thread about this at 3D Audio where a few people have said a master clock can make a marked improvement. An AudioMedia II card can't receive wordclock directly, but since you're digitally syncing/slaving it to another device it would piggyback along for the ride. And this is from the manual for the 888/24: "The 888/24 I/O can only synchronize to and receive word clock lock on channels1?2 of its digital inputs. To synchronize your system to an external digital clock source, it must be connected to digital inputs 1?2 of the 888/24 I/O. In an expanded Pro Tools system, the system clock is carried by the Audio Interface connected to the first Pro Tools card in your system. This Audio Interface will act as the master interface in your system. All other Audio Interfaces will be slaved to it."

Which Rosetta do you have? Unfortunately, the original Rosetta AD doesn't have any digital inputs or word clock in.

Paul

tuchel

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Re: Digital Clock Sync
« Reply #2 on: May 12, 2005, 08:35:13 AM »

Yes that muddies the water, the Rosetta only has word clock out. I've been syncing to it during tracking, so I imagine thats the biggest benefit.  The 888/24 has slave in/out BNC's I assumed that was for sync, not so?  Maybe my set up won't benefit from an external clock.

Thanks
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PaulyD

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Re: Digital Clock Sync
« Reply #3 on: May 15, 2005, 01:32:52 PM »

Here's what I'm picturing (correct me if I'm wrong Smile):

Your 888 is your main audio I/O device. You start and stop playback with the computer that is connected to it. The computer with the AM II card is slaved to the 888 and chases to whatever the "main" computer is doing. You're using an analog mixer or summing device and the Rosetta is your 2-mix device. If this is correct, I'd say you're doing the right thing now by using the Rosetta as the master clock. It seems to me the strength of Apogee's products are the clocks. I assume your ears have already told you it's better than the 888's internal clock.

So, I guess the question is, if you let the Rosetta run on its own and clock the 888 and AM II with another clock, will you get improved audio? Again, the only way to find out is to connect another clock to the 888 and listen carefully. This is why I encourage you to rent one if you can (or buy from a place with a no-questions-asked money back satisfaction guarantee). If you're straining to hear a difference between the clock coming from the Rosetta vs something like a Big Ben or Lucid GenX 6, the money would be better spent elsewhere. I have found that if something is really making a worthwhile difference, even if it's subtle, I'll notice it immediately. It's like "Whoa! Okay, cool. This thing is doing what I'd hoped it would do..."

Paul

tuchel

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Re: Digital Clock Sync
« Reply #4 on: May 15, 2005, 07:56:11 PM »

Pretty much right, I mix in the box, no external mixer.  The 888 is clocked by the rosetta. The 2nd computer acts as a add on external sampler. Samples triggered by midi, come out spdif convert to AES and enter into a digital AES input of the 888.  If I select external sync in the computer #2's software does it then clock from the rosetta, who is master clock to the 888?
I guess I listen for improvement when I get it to work...

Since the 888, I have learned, is in sync using the AES in, and there is no way to clock in the rosetta, The rosetta becomes useless in a set up with an external clock. So a clock would have to make the 888 better sounding than the rosetta.
I find it odd than the BNC inputs on the 888 don't sync the clock.
The only way to really get a legit clock set up, would be to have a A/D that syncs to clock and possess a sound I liked.  Other than that clock sync with the rosetta is getting a better performance from the setup, but not the best.


Hmmm


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zetterstroem

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Re: Digital Clock Sync
« Reply #5 on: May 16, 2005, 02:15:35 AM »

tuchel wrote on Mon, 16 May 2005 00:56

Pretty much right, I mix in the box, no external mixer.  The 888 is clocked by the rosetta. The 2nd computer acts as a add on external sampler. Samples triggered by midi, come out spdif convert to AES and enter into a digital AES input of the 888.  If I select external sync in the computer #2's software does it then clock from the rosetta, who is master clock to the 888?
I guess I listen for improvement when I get it to work...

Since the 888, I have learned, is in sync using the AES in, and there is no way to clock in the rosetta, The rosetta becomes useless in a set up with an external clock. So a clock would have to make the 888 better sounding than the rosetta.
I find it odd than the BNC inputs on the 888 don't sync the clock.
The only way to really get a legit clock set up, would be to have a A/D that syncs to clock and possess a sound I liked.  Other than that clock sync with the rosetta is getting a better performance from the setup, but not the best.


Hmmm




if you switch the 888 to external (aes) clock you loose the wordclock sync.... so you have to sync the audiomedia 2 to the 888 or rosetta ..... or it will sound a great deal poorer than it could....

the problem her is i don't know if the rosetta has 256x superclock out as the 888 needs.... but i doubt it..... but if it does... clock the 888 to the rosetta and the audiomedia to the 888 and be happy

or be even happier and buy this: http://www.rosendahl-studiotechnik.de/nanosyncs.html    it has all you need and makes the 888 sound SOOOOOO much better..... will never forget the day we strapped on of these on our system......
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tuchel

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Re: Digital Clock Sync
« Reply #6 on: May 16, 2005, 10:47:50 AM »

Sounds cool. How do you hook up the Rosendahl with a system like mine? Remember the Rosetta doen't have word clock in.

Terry
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zetterstroem

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Re: Digital Clock Sync
« Reply #7 on: May 16, 2005, 12:05:29 PM »

what model is it?
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Noting the music industry's complaints that illegal downloading means people are getting their music for free, he said, "Well, why not? It ain't worth nothing anyway." (b.dylan)

tuchel

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Re: Digital Clock Sync
« Reply #8 on: May 16, 2005, 01:48:03 PM »

It's the first Rosetta model (labeled the solution series), Rosetta AD 24 bit 44.1-48.
The 888/24 has 8 dig ins and outs, it has BNC's labeled "Slave In" and "Slave Out". According to the manual the first two AES in's can sync to clock.
My simple mind wonders what benefit there is recording into the Rosetta, and sending it into a 888/24 with a better clock. Since the Rosetta will not be "in sync" with the properly syncronized 888/24. Shouldn't they all be in sync to hear a benefit?

Or am I missing the point that an 888/24 in sync is better than the first generation Rosetta?

Terry

PS I've beem using the Rosetta as master clock for years, and it's better than the 888/24 on it's own, but not "tears running down my face" better.
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PaulyD

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Re: Digital Clock Sync
« Reply #9 on: May 16, 2005, 03:12:52 PM »

Terry,
I have an Apogee Mini-Me. Like the Rosetta AD, it has no word clock in. Whenever a Mini-Me is digitally interfaced to anything, it must be the master clock. I suspect this is likely true of the Rosetta AD. To know for sure, I'd call or email Apogee tech support. I've contacted them a few times with pre-sales questions and their service was good. No hold time on the phone to reach a tech and usually a same-day or next-day response to email.

Paul

zetterstroem

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Re: Digital Clock Sync
« Reply #10 on: May 17, 2005, 06:26:23 AM »

ok.... you could continue to let the rosetta be masterclock via aes/ebu or send the wordclock out of the rosetta into something that can convert it to 256x superclock (like the nanosyncs/nanoclocks/apogee bigben)
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tuchel

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Re: Digital Clock Sync
« Reply #11 on: May 17, 2005, 09:24:46 AM »

That makes sense. I could use the BNC out of the Rosetta, into a sync box, the sync box would then output 256 superclock, which would make the 888/24 a whole lot better. So it's the 256 superclock that does the magic.
Let me continue to try your patience...

-Can the BNC "Slave in" on the 888/24 ever be used for 256 superclock sync?

-If the software sync setting in Pro Tools is set to external, and both the Rosetta and the Big Ben/Nano are showing up at the AES in with timing information, what would it pick and why?

-And in if the sync Box creates timing in the 888/24 by way of an AES in, that effectively makes the 888/24 a (digitally speaking) 6 channel input Box. You give up 2 channels to sync the box?

-I don't understand timing in this respect; If the Rosetta is putting out a good quality clock rate, does the sync box improve on it? Does it make the 888/24 a higher quality receiver? In my mind I am thinking that the chain is only as strong as it's weakest link. So the entire set up, with my theory, is that it will never be more stable than the Rosetta clock.
Conversely, if everything could be in sync together, and you told me a higher quality clock was now running everything more exactly, well I get that.

Then again, if you just say to me: Just shut up, buy it you'll be a bunch happier, I'll understand.

Terry


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zetterstroem

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Re: Digital Clock Sync
« Reply #12 on: May 17, 2005, 11:19:15 AM »

tuchel wrote on Tue, 17 May 2005 14:24

That makes sense. I could use the BNC out of the Rosetta, into a sync box, the sync box would then output 256 superclock, which would make the 888/24 a whole lot better. So it's the 256 superclock that does the magic.
Let me continue to try your patience...

-Can the BNC "Slave in" on the 888/24 ever be used for 256 superclock sync?

that's what it is!

-If the software sync setting in Pro Tools is set to external, and both the Rosetta and the Big Ben/Nano are showing up at the AES in with timing information, what would it pick and why?

external=aes/ebu.... internal=superclock

-And in if the sync Box creates timing in the 888/24 by way of an AES in, that effectively makes the 888/24 a (digitally speaking) 6 channel input Box. You give up 2 channels to sync the box?

yes... another reason to use superclock

-I don't understand timing in this respect; If the Rosetta is putting out a good quality clock rate, does the sync box improve on it?

yes it does... it lowers the jitter.... and thereby raises the quality of the clock/sound

Does it make the 888/24 a higher quality receiver? In my mind I am thinking that the chain is only as strong as it's weakest link. So the entire set up, with my theory, is that it will never be more stable than the Rosetta clock.

no as i decribed before...

Conversely, if everything could be in sync together, and you told me a higher quality clock was now running everything more exactly, well I get that.

Then again, if you just say to me: Just shut up, buy it you'll be a bunch happier, I'll understand.

Terry



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Noting the music industry's complaints that illegal downloading means people are getting their music for free, he said, "Well, why not? It ain't worth nothing anyway." (b.dylan)

tuchel

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Re: Digital Clock Sync
« Reply #13 on: May 17, 2005, 10:22:21 PM »

Thanks!
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tuchel

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Re: Digital Clock Sync
« Reply #14 on: May 18, 2005, 10:20:11 AM »

Has anyone tried out the Lucid GENx6-96 Word unit?
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