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#1121136 - 05/03/12 05:38 AM DIF-AT, question about synchronization
astronaut Offline
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Registered: 04/17/11
Posts: 42
greets

So I received a DIF-AT converter box.

Here is the chain connections:

Roland VSR-880 (R-Bus output) to DIF-AT, ADAT output to Alesis io14

1) The DIF-At has an ADAT sync connector (serial). I guess I won't be able to sync the DIF-AT with the Alesis io14 with just the one optical cable?

2) Are there any RCA (Spdif) to Serial sync adapters/cables? Is it possible to use the spdif out on the Alesis to send the clock signal to the ADAT serial input on the DIF-AT?

thanks for any input


Edited by astronaut (05/03/12 05:50 AM)

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#1121153 - 05/03/12 08:41 AM Re: DIF-AT, question about synchronization [Re: astronaut]
uptildawn Offline
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Registered: 12/15/01
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I can't say I understand exactly when the adat sync connection is needed, but it seems to me that using a single optical cable between the io14 and the dif-at is all you need to get digital audio to the alesis/pc.

Have you tried it to see if you have sync problems?
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uptildawn

2013 Iowa City JazzFest sets!
Dr Lonnie Smith Trio w/Jonathan Kreisberg on guitar
Pharoah Sanders Quartet
Fred Hersch Trio
These are post mixes set to single camera video (by Rich Rauch).

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#1121165 - 05/03/12 10:22 AM Re: DIF-AT, question about synchronization [Re: uptildawn]
bear Offline
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Registered: 10/25/99
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Loc: abq,nm,usa
The optical audio should sync fine - the 9 pin serial sync connector is more for transport control on real ADAT decks.
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#1121175 - 05/03/12 10:49 AM Re: DIF-AT, question about synchronization [Re: uptildawn]
astronaut Offline
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Registered: 04/17/11
Posts: 42
 Originally Posted By: uptildawn
Have you tried it to see if you have sync problems?


I'm not sure how to do that. All I did was connect the devices together. The DIF-AT has only the power light on. the ADAT led is off. I've tried to sync the VSR-880 to the DIF-AT, but that did not work, I found out later that the DIF-AT has no internal clock.

Then I tried syncing the Alesis io14 to the DIF-AT, also did not work.

I'm not sure how I could test the DIF-AT to see if it's working properly.


Edited by astronaut (05/03/12 10:50 AM)

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#1121194 - 05/03/12 11:33 AM Re: DIF-AT, question about synchronization [Re: astronaut]
uptildawn Offline
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Registered: 12/15/01
Posts: 8509
Loc: Iowa
What do you mean, exactly, by "it did not work"?

Do you mean that you tried to hook up the VS, DIF and io14 to the PC, establish an audio connection between the VS and PC and that did not work?

I don't know the DIF and the R-BUS connection hookups, so I'm going blind here....

Isn't the DIF just a go-between from the VS to PC? The sync should happen between the VS and io14, right? Basically, that you need digital lock between the PC hardware/software and the digital I/O of the VS.... correct?

As bear points out, you shouldn't need the ADAT sync unless you're connecting to a device specifically designed to work with it, such as an ADAT machine. I've never once used the ADAT sync on my RME hardware and haven't had any problems establishing digital lock/sync between multiple preamps and the RME/PC hardware.

Seems to me that the ADAT/optical cable should provide the digital path between the io14 (and its FW connection to the PC) and the DIF and that the R-Bus should provide the digital path between the DIF and VS..... right? Or does the digital link to the VS require an optical/coax cable between the DIF and itself, besides the R-Bus... I'm at a disadvantage here, not having used these things before.

The io14 must have some software control of the digital path preferences (adat, or spdif connection, for instance).... Does it? If so, the sample rate and preferred signal path would be established between the io14 software and your PC daw software settings.

The DIF would receive its signal path and sync information from the VS and PC and sync/lock would occur when the VS and PC have matching sample rates.... No?

If the DIF has no manually controlled adjustments, then what else is there to make things work? Or am I in way over my head???
_________________________
uptildawn

2013 Iowa City JazzFest sets!
Dr Lonnie Smith Trio w/Jonathan Kreisberg on guitar
Pharoah Sanders Quartet
Fred Hersch Trio
These are post mixes set to single camera video (by Rich Rauch).

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#1121198 - 05/03/12 11:44 AM Re: DIF-AT, question about synchronization [Re: uptildawn]
astronaut Offline
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Registered: 04/17/11
Posts: 42
I have just tried something that might shed some light onto this problem:

I have an Event EZ-BUS digital mixer. It has ADAT IN and OUT (the Alesis IO14 has only ADAT IN).

I hooked up the Ezbus to the DIF-AT and wanted to choose the DIF-AT as the master clock, the Ezbus was showing that only 48KHZ clock is available from the DIF-AT. Could that be the problem? Is there a way to set the 48KHZ to 44.1KHZ? It's also strange since the DIF-AT has no internal clock (according to info on the NET), should it not set itself automatically to the 44.1KHZ of the VSR-880?

I also tried another connection: VSR-880 optical out to EzBUS ADAT in. It worked, I got the master mix output to be audible on the Ezbus input channels 1 and 2. Both when the Ezbus was synced to the VSR-880 and when it was using its internal clock set to 44.1KHZ.

So my guess is that because the VSR-880 is set to 44.1KHZ and the DIF-AT is somehow stuck in 48KHZ clock mode, the two devices can't sync.


Edited by astronaut (05/03/12 11:46 AM)

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#1121200 - 05/03/12 11:59 AM Re: DIF-AT, question about synchronization [Re: astronaut]
bear Offline
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Registered: 10/25/99
Posts: 6225
Loc: abq,nm,usa
If I am remembering correctly, the ADAT interface only works at 48k. With a special SMUX mode it could be kicked to 96K at the expense of half the channels.

I could be wrong, but I do not think the ADAT can be made to run at 44.1


 Originally Posted By: astronaut
...I also tried another connection: VSR-880 optical out to EzBUS ADAT in. It worked, I got the master mix output to be audible on the Ezbus input channels 1 and 2. Both when the Ezbus was synced to the VSR-880 and when it was using its internal clock set to 44.1KHZ.


I think when hooked up this way you are using SPDIF NOT ADAT. ASFAIK the VSR does not have an ADAT port

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#1121208 - 05/03/12 12:40 PM Re: DIF-AT, question about synchronization [Re: bear]
astronaut Offline
Planeteer


Registered: 04/17/11
Posts: 42
 Originally Posted By: bear
If I am remembering correctly, the ADAT interface only works at 48k. With a special SMUX mode it could be kicked to 96K at the expense of half the channels.

I could be wrong, but I do not think the ADAT can be made to run at 44.1


I think the older Alesis recorders were 48khz only.

 Quote:
I think when hooked up this way you are using SPDIF NOT ADAT. ASFAIK the VSR does not have an ADAT port


Yep. But I only wanted to see if the EZBUS will sync to the VSR-880 if connected directly. The ADAT ports on the EZBUS can handle both, ADAT (8ch) and 2-channel digital audio signals.

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#1121217 - 05/03/12 01:26 PM Re: DIF-AT, question about synchronization [Re: astronaut]
astronaut Offline
Planeteer


Registered: 04/17/11
Posts: 42
one more thing. When the DIF-AT is connected to the EZ_BUS, both IN and OUT, the ADAT led is on.
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#1121243 - 05/03/12 04:25 PM Re: DIF-AT, question about synchronization [Re: astronaut]
astronaut Offline
Planeteer


Registered: 04/17/11
Posts: 42
I've just tried reloading the same project and I've got a signal goin from the VSR880 to the Ezbus but the channels are messed up.

afaik the R-BUS is supposed to transmit the 8 tracks separate i.e. the EZBUS should be receiving them separate, but I have a different situation: The EZBUS is receiving the VSR880 Main MIX (with all effects) on channels 1 & 2, and on channels 7 & 8 it is receiving the same main mix but without the effects. Now this is weird.

maybe there is some option in the VSR-880 that makes it behave this way?

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#1121833 - 05/07/12 02:39 PM Re: DIF-AT, question about synchronization [Re: astronaut]
astronaut Offline
Planeteer


Registered: 04/17/11
Posts: 42
I took the box apart, looks clean, nothing burned. There are two tactile switches on the circuit board, does anyone know what they do?
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