Re: Audio link two computers in real-time: ethernet?

[Rainer Straschill <moinsound@googlemail.com>]

Per said (about using S/PDIF or ADAT to send audio between two computers):
> Good things is you don't get any extra latency in the signal, since you 
>are not taking that extra AD/DA tour when sending the already digitized 
>signal directly into the other computer's digital input.

That is not correct. The main part of the latency of two computers
interfacing are the interfaces' audio buffers (which are usually in
the ms range) - the latency of the converters are (at least) one order
of magnitude below that.
So by using digital interfaces, you're able to reduce your
inter-computer latency from e.g. 6.3ms to 6.0ms.
(additional reading: http://www.moinlabs.de/e_lat.htm)
One reason to do as you describe is that a) you don't do additional
converter passes, b) you can sync your entire setup to the most stable
interface clock of all.

> But I think it has to be the gigabit ether net, not the older and slower 
>version that are still to be found in old computer hardware.

There's an issue with ethernet (or rather its implementations on
typical workplace computers), and that is that the computers are not
able to handle a high-bandwidth ethernet data stream with low latency
(sic!). They do perfectly well deal with those stream on average,
however, while a constant throughput of even 100MBit/s (aka the older
slower version that are still to be found) will create problems.

Incidentially, Steinberg uses digital audio interfaces (as you
suggested) when spreading system load over different computers, not
ethernet.

Best,

            Rainer