What are the Advantages/Disadvantages of the different digital I/O interfaces???

[nova]

Hello All,

To my knowledge, there are currently three different types of digital I/O
interfaces that are used in digital audio, SPDIF, ADAT Lightpipe, and
AES/EBU. I love the fact that I have choices, but when it comes to digital
I/O I can't help but wonder what differientiates one interface from the
other. I mean digital is digital right. I take it that the reason there
are three types is because different manufactures implemented what was best
for them at the time. But aside from that, are there other things going on
under the hood that would make a difference in sound quality??? What is the
best???

Thanks.

dj

[Scott Dorsey]

nova > wrote:
>
>To my knowledge, there are currently three different types of digital I/O
>interfaces that are used in digital audio, SPDIF, ADAT Lightpipe, and
>AES/EBU. I love the fact that I have choices, but when it comes to digital
>I/O I can't help but wonder what differientiates one interface from the
>other. I mean digital is digital right. I take it that the reason there
>are three types is because different manufactures implemented what was best
>for them at the time. But aside from that, are there other things going on
>under the hood that would make a difference in sound quality??? What is the
>best???

There are actually dozens of different kinds. Of the ones you mention,
SPDIF runs 2 channels over 75 ohm cable, AES/EBU runs 2 channels over
110 ohm cable. Which one you want depends on whether you have existing
cable infrastructure already. They both send data and they can both handle
the same subcode now, so you use the one that you have the cabling in place
for.

ADAT Lightpipe handles eight channels. It's got a fairly high error rate
so you can't go very far with it, but when you need to put eight channels
on a line, Lightpipe or the competing format, T-DIF is the way to go.

Then there are formats like MADI and P-DIF..... You use them because you
are connecting to equipment that has them.

Bits are bits, but there are lots of ways to get bits from one place to
another, and if you already have a cable plant with tens of thousands of
feet of 75 ohm video cabling, you probably want to use S-PDIF rather than
pulling new cable. Likewise if you have a cable plant with a lot of twisted
pair lines, you can use existing cable and patchbays with AES/EBU and get
away with it.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."