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ADAT Optical I/O query

Discussion in 'Pro Audio Equipment' started by timshel, Nov 7, 2012.

  1. timshel

    timshel Active Member

    Hola Folks,

    My brain has been melted while looking for a new audio interface or some way to augment my current set-up.

    I am running an Apogee Ensemble at the moment and the 8 channel I/O is no longer enough for what I am doing. My profile is up to date if you'd like more information.

    So the question is: If I bought another audio interface of similar build 8X8 (MOTU is looking good for the price) that has optical In and optical Out, would I be able to use each as 8 channels in and 8 channels out?

    I am aware that optical is 8 channel at 24bit 48kHz. Perfect! I cannot find anything which verifies that a device can send 8 channels on both sides of the I/O. Are they separate data streams? does the optical in/out cover only 8 channels total or 16 channels total?

    Please no comments about combining converters or why would you want to do that blah blah blah. I am aware of the timbre differences but another Apogee Ensemble is out of reach at the moment. And if I cannot do 8 in, 8 out through ADAT Optical I will just buy a larger system!

    Much love audio geeks.
  2. MrEase

    MrEase Active Member

    I'm not sure if that's the way to go. The MOTU will be either Firewire or USB2 for control so you will need to link it up together with you Apogee and then sync them. In this case the ADAT becomes redundant.

    I know that Behringer do the ADA8000 which is just a box of 8 A-D and D-A's with ADAT I/O. No control is needed with this box and it would achieve what you need.

    Of course I know I've used the "B" word here, which is anaethema to some, but currently I do not know of any alternative manufacturer of a box with the same functionality.
  3. MrEase

    MrEase Active Member

    BTW, there's a sound on sound review of the ADA8000 here. Behringer ADA8000
  4. timshel

    timshel Active Member

    I have had issues when trying to daisy chain audio interfaces with firewire. Most are not designed to be used that way or if they are, they want you to use the same interface. Which is Apogee's problem. For some reason they never expected anyone to use two?

    The ADAT connections are much more reliable than the firewire in any case. Plus I can tell people their music is traveling at the speed of light. Always cool.

    The Behringer came across my list but the question still remains unanswered: Can you do two streams of 8 channel ADAT (16 total) or is the I/O restricted to 8?

    Appreciate the thought though.
  5. MrEase

    MrEase Active Member

    Sorry, I missed that part out. As there are two optical cables, each one handles data in a single direction. In other words you can be recording 8 channels whilst playing back another 8 - all at the same time. The only restriction is that they use the same clock.
  6. timshel

    timshel Active Member

    Wunderbar! Any documentation that you know of for future reference?

    I figured it was going to be that way but the Ensemble manual is TERRIBLE. Everything else kept saying '8 channels of I/O! 8 channels of I/O!' Blegh. The clock will be Apogee so no qualms about that.
  7. MrEase

    MrEase Active Member

    I don't have any good documentation on ADAT other than similar manuals to yours. I do use it though, so I can vouch for how it works.

    BTW when I said the same clock, I meant the sample rate clock. So you can't use 44.1kHz for record and 48kHz for playback at the same time.
  8. Boswell

    Boswell Moderator Distinguished Member

    While it varies from system to system, most interfaces that say they have "optical I/O" mean they have either or both of 2-channel optical S/PDIF input and output or optical ADAT input and output (8 channels each way at standard sampling rates per connector, 4 channels at higher sampling rates).

    Your Apogee Ensemble has 1 input and 1 output ADAT optical connector. The ADAT input can be used for 8 additional input channels and (independently) the ADAT output used for 8 additional output channels. These appear and can be assigned in the Maestro routing tables.

    To use these channels you would need a box that had ADAT I/O, either 8 ADC inputs or 8 DAC outputs or both. Note that you can get boxes (like the ADA8000 you mentioned) whose I/O is performed only via ADAT, or you can get boxes that have multiple functions and can be set up so that the inputs and outputs are via ADAT. When used in its stand-alone mode, the Ensemble performs as one of these.

    I haven't done a recent count of available ADAT I/O units, but taking both sorts into account, it would not surprise me if it came to over 20 different ones.
  9. MrEase

    MrEase Active Member

    I agree with Boswell, if you have a unit that can be used in standalone mode it can be hooked up via ADAT without having to worry about using multiple (and different) soundcards. The reason I mentioned the ADA8000 is that it does offer an additional 8 Mic preamps. Many of the (20 or so) ADAT enabled Soundcards (Like my ageing MOTU828) only have two or four mic channels. I guess it depends how many Mic channels you need as opposed to Line inputs.

    At the price point of the ADA8000, it is hard to argue against from the value for money aspect - even taking in to consideration some peoples opinion of the manufacturer. As Boswell suggested, a search for similar units may be worthwhile as only you are fully aware of your overall requirements.

    Good Luck!
  10. timshel

    timshel Active Member

    I am really just interested in increasing the amount of D/A and A/D converters. Just won an Ebay bid on a MOTU 828 mkII for $300. Standalone for the win!

    It is a pain in the ass to use the Maestro software because it fights with other interfaces. Appreciate the advice peoples, I have increased my studio to 16X16! Still have SPDIF to mess with too. Joe Meek Twin Q is looking pretty tasty at the moment.
  11. Boswell

    Boswell Moderator Distinguished Member

    That looks like a good catch. It gives you two internal mic pre-amps and 6 further line inputs for use with external pre-amps.

    Using either the front panel controls or their Cuemix Console program, you can set it up to route the digitized input channels out via ADAT. This setting uses up all the internal buses, so I don't think you could have the 828's ADAT inputs routed to its analog outputs at the same time.

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