Check your egos at the door! Real-time audio streaming via ethernet.

[blahblah99]

I'm not talking about real audio where data is queued and buffered, rather, data should be streamed real-time, as in the case of a live concert. There are a couple of solutions out right now, mainly Cobranet and Ethersound, that uses all aspects of ethernet technology to stream audio.

The main problem of streaming real-time audio is clock synchronization and deterministic data delivery. Ehernet is usually ran at 20/25Mhz and audio at 24.576Mhz, or a lower multiple of that. Added to that is the problem of latency through busy network switches and packet loss.

 

[Lynx516]

Audio usually is at 24ish Khz. No reason to sample faster than 50khz with audio (lets say 100khz)

if you have noticable increased latency through a switch because its busy you are using the wrong switch. Same goes for packet loss.

I dont see huge problems but as most sound systems use XLR cables (so do most conserts) to move sound around (i.e. form mic to desk) and as the desks are analogue the biggest latency hit will be the conversion from A to D and back again.

I dont see why there would be any clock syncronisation problems. Unless you mean that to be wave front syncronisation with staggered speakers which will always be a problem even without using ethernet. And 100 Base T should have enough overhead to say when a packet has arrived.

 

[jtusa]

Wouldn't that just be VoIP?

 

[blahblah99]

Originally posted by: jtusa4
Wouldn't that just be VoIP?

No, VoIP is probably bandlimited and lower quality than high fidelity audio. Not to mention its non-real time, as in there can be hundreds of milliseconds of delay, which is unacceptable in any venue that requires real-time audio, such as a movie theatre.

 

[f95toli]

What's wrong with Firewire? It is already available on some AV-recievers and DVD-Players, there is also another digital standard (HDMI?) which can transfer sound in "real-time".

But, as has already been pointed out, high-quality audio at 192 (DVD-A) kHz can easily be transfered withot any delay over a normal network, if you really want to you can include a clock-signal to handle the sync (as in HDMI).

 

[blahblah99]

Originally posted by: f95toli
What's wrong with Firewire? It is already available on some AV-recievers and DVD-Players, there is also another digital standard (HDMI?) which can transfer sound in "real-time".

But, as has already been pointed out, high-quality audio at 192 (DVD-A) kHz can easily be transfered withot any delay over a normal network, if you really want to you can include a clock-signal to handle the sync (as in HDMI).

I don't think firewire can do 100m like cat5. Otherwise I'd be over that like flies on honey!

Basically the requirements are:

1) Has to be near real-time streaming audio (ie, less than 5ms of system delay)
2) Has to travel over long distances, up to 100 meters.
3) Has to be high fidelity.
4) Has to be capable of streaming multi channel audio, up to 64 channels one way or 32 ch bidrectional.

Cobranet is just too damn expensive to implement, firewire and usb only covers short distances? I havn't heard of HDMI, but I'll have to look into that.

 

[Shalmanese]

Have you had a look at the RTP or RTTP? AFAIK, that's a protocol solution that does exactly what you need and runs off normal cat5 ethernet.

 

[Rainsford]

Originally posted by: Shalmanese
Have you had a look at the RTP or RTTP? AFAIK, that's a protocol solution that does exactly what you need and runs off normal cat5 ethernet.

Yeah, I agree. My understanding is "real time" is a relative term when running this over the Internet, but for local networks it is EXACTLY what you are looking for.

 

[Monster Duck]

Streaming Hi-Fi audio-only over the internet has limited application. It needs to be streamed with video Standard or Hi-Def. Those have another set latency issues.

You might want to grasp the problem completely.

 

[BespinReactorShaft]

A chain of Firewire repeaters?

"FireWire nodes are best kept 4.5m or below from each other to retain data integrity, and the total aggregate distance for a series of daisy-chained nodes should be 72m or less, with no more than 16 hops."

Or maybe somethin like this:

http://www.compumodules.com/ne...ms/ovk-ovk-1394r.shtml

http://www.google.com/search?h...rewire&btnG=Search

Note that I've not factored in any $$$ budget considerations.