what audio interface is good for me?

[majistik]

I need about 7 stereo AES/EBU digital i/o for my gear
what is my best option?
the far as I got was:

1 X Mark of the Unicorn (MOTU) 2408 mk3
PLUS
2 X Alesis Format Converters (such as the AI-4)
(one connected via 4 adat ports to the 2408 mk3)
(one connected via 4 tdif ports to the 2408 mk3)

as far as i understand this will give me 8 stereo digital AES/EBU i/o.
is it smart doing it that way (price?,quality?)
what are my other options.

thank you.

[C00kie]

What exactly do you need "about 7" aes/ebu ports for? What's to be connected?
Would you use rca, xlr or optical connections?

[majistik]

xlr
some for gear that i have and some for equipment that i wish to buy in the future.

thank you.

[C00kie]

The MOTU 2408 features three ADAT ports, and each of those carry 8 mono channels. So you don't need to use the TDIF ports to connect two Alesis AI-4 units. Each of those take one ADAT port and convert it into four (stereo) AES/EBU ports.

Maybe the biggest problem you'll run into is clock synchronisation. I'm no expert on that subject, but I've heard it can be a nightmare to sync that many devices.

I have no opinion on price or quality. But I've heard MOTU excells when connected to Apples, but can be flakey when used on PC's. The other option would be a RME card with three ADAT ports.

[majistik]

ok thank you.

are you sure that one tdif input and one tdif output will give 8 mono channel on the Alesis AI-4?
becuase for some reason there are "2 ADAT Optical ins and outs"
why is that?



another question:
RME card with three ADAT ports (model 9652) seems nice.
is it better then my option?
i dont know anything about sync and word-clock.
I have searched on the internet and found nothing that i understand.i dont know many about hardware.
please tell me what it is in general and if i shold worry about it.

thank you.

[C00kie]

are you sure that one tdif input and one tdif output will give 8 mono channel on the Alesis AI-4?
becuase for some reason there are "2 ADAT Optical ins and outs"

Where did you get that info? Look at http://www.motu.com/products/pciaudio/2408 and take the interactive tour. On the back you can see three adat ports, and each adat port carries eight mono channels. Three times eight is twenty-four channels on adat.

Forget about tdif, use adat whenever you can... Unless you already have gear with tdif ofcourse.

RME card with three ADAT ports (model 9652) seems nice. is it better then my option?

RME is more popular than MOTU. Don't ask me why.

i dont know anything about sync and word-clock.
I have searched on the internet and found nothing that i understand.i dont know many about hardware.
please tell me what it is in general and if i shold worry about it.

Eac digital audio device has it's own chrystal dictating the clock frequency. If you have more than one, then one of those must be appointed the master and the others are slaved to that. Otherwise they will run on slightly different frequencies and your audio samples won't line up, resulting in stutter and errors.

For this problem there is word clock. This is a protocol to transfer clock pulse signals from device to device. Those are the BNC connectors next to the power socket at the back of the motu 2408. You'll probably need an extra word clock generator device, and good ones can be very expensive.

[majistik]

Ok, thank you very much again.

still about the "2 ADAT Optical ins and outs",I was talking about the "Alesis AI-4".
Why does it has "2 ADAT Optical ins and outs" and not one?

I understand the 2408 has 3 ADAT stereo digital i\o...
and the MOTU 9652 also has 3 ADAT stereo digital i\o...

how the connection to the "Alesis AI-4" being done? (is it takes 2 stereo ports from the audio interface or just one stereo port?)

[C00kie]

Ah right, the Alesis AI-4 indeed has two ADAT Toslink connections. The reference manual sheds some light on that:

The ADAT optical interface includes a pair of TOSLINK-style transmitters and two TOSLINK-style receivers. By dividing the connections into pairs, we're able to support eight channels of 24-bit audio at sample rates of up to 96 kHz.

ADAT can carry eight mono channels, but only up to 48kHz. When you double the sample rate it can only carry four mono channels. That's when the second connection can be used, so you still have eight mono channels.

Those eight channels from ADAT inputs/outputs are converted to four (stereo) AES/EBU connections. So since you want seven stereo pairs (fourteen mono channels) you'll require two of these boxes.

[majistik]

I think i will go for the RME with two Alesis AI-4.

Thank you!!!!!!