Audio over Ethernet - Linking different departments using our standard College ethernet network.

[benniferj]

Hi,

At the college i'm at i'm currently installing a Sonifex based radio studio ready for local broadcast. As part of the students shows, they are having bands playing live in the music block and need 2 way communication between building. The difficulty is that the radio studios are about half a mile away from the music block.

Until now, my plan has been to run an 8way multicore all the way to the other end (using powered DI boxes/DAs to reproduce the signal to prevent loss due to the massive distance...)

Was just thinking though, what are my options regarding using our existing ethernet network. My department works closely with the computing department... is there a software based audio over ethernet solution that can send, at minimum, a stereo feed from the radio studio (our pfl/cuemix) and return a stereo output from the mixer in the music block (so 2 way communication?). We have some 8in/out soundcards that we can use on the machine running at each end to deal with audio coming in/out of the systems, interfacing with mixers at each end.

Its just not something I know about... anyone know of any solutions, ideally cheap?

Cheers,
Ben

[muzines]

Could you give some idea as to what computers you are using?

No point recommending a Mac solution if you require a PC solution...

[julestech]

At our college we have looked at this before. No need at present to do it so this is untried but we looked at the roland digisnakes which use standard cat5 with audio breakout boxes at each end (or the Vmixer if you have one).

Alternatives would be BSS soundwebs, A&H iDR8 or any of the other audio over ethernet solutions. There are other options out there. It all depends on budget (what doesn't?...)

[muzines]

I thought the OP was asking for a software-only solution, though.

[Wease]

Hi,

At the college i'm at i'm currently installing a Sonifex based radio studio ready for local broadcast. As part of the students shows, they are having bands playing live in the music block and need 2 way communication between building. The difficulty is that the radio studios are about half a mile away from the music block.

Im curious to know if you're broadcasting live or not....cause any solution is going to have latency issues if going live.

now, i'm not at a college, but at school we pre-record everything. this kinda solves the issue for us, as we pre-mix. We're a special school so live broadcasting isn't really an issue for us, so we just send pre-mixed stuff over our school intranet quite easily then join this prerecorded material to our broad(pod)casts

I'm not so sure that even the BBC broadcast live music completley live anymore?....maybe live lounge, but even then they (the presenters) are usually in the same studio as the performers and everything leaves one studio.

1/2 a mile seems an awfully long distance....wouldn't it be easier and more effective to have a live session recorded away from the radio station or even better, a sub-radio station in the live area?

Please, someone state if i'm wrong, but i'd be very worried about dead air during the wait between the presenter in the studio and the live band starting....

never heard of a situation where the whole feed came from 2 distinctly different places....and the disruption to the rest of the college's network (or their disruption to you're shows if the network was 'full' would worry me!

[James Perrett]

It might be worth looking at Reaper with the ReaStream plug-in. However, you really need to make sure that the network won't be heavily loaded while you are doing this so you may need to set up a separate network to do this if you have sufficient cabling between the sites.

Cheers

James.

[Aftertouch]

Whilst I cannot reccommend a solution for you, it is worth pointing out that the buildings are almost certainly going to be interconnected by fibre due to the limitations of copper LAN cabling (Cat5 & Cat6 etc).

You might therefore find that some hardware based audio over ethernet solutions are reliant on the twisted pair wires inside a Cat5/Cat5e or Cat6 cable.

A software solution is unlikely to care what the cabling infrastructure is and should just work. This may well be the same for some hardware solutions, but I haven't used any personally.

As the final transmition medium is "only" radio, maybe you should look at a few VoIP or video conferencing software solutions and see what audio performance you can get out of them. After all, they are designed for near realtime communications. Worth a try.

Whatever solution you go with, make sure that your IT guys set up a VLAN so that your audio has guaranteed, uninterupted bandwidth.

[Hugh Robjohns]

Trying to send audio reliably over a general purpose data network is rarely a happy situation. Network loading and other routing issues will cause variable latency issues if it works at all. You'd be better off running a dedicated set of lines -- which could be ethernet if you want, but dedicated to your audio use only -- and go for a purpose designed audio protocal that ensures a reliable realtime service with a fixed latency. The Roland system would be one very convenient option, and could cover that distance with a few standard ethernet switches along the way to regenerate the signals.

And to answer the comment from another poster, yes, the BBC still does lots of realtime live broadcasts.

hugh

[benniferj]

Desmond, its PC or Mac, we can spare a few computers of either type for this special event (our one month RSL broadcast license).

Definitely looking for a software based solution - I always figured a hardware solution relying on dedicated boxes on either end would have problems, indeed with fibre channel and the complex switching going on in the server rooms.

We are really wanting to do things totally live, the only issue really is the distance, and the latency! Mixdowns are easy, to produce and export, but we're trying to avoid doing prerecords (students are being assessed as recording live, so we want to keep that as true as possible) + we were hoping to run interviews with the band being up in the recording studio after playing, and presenters in the radio studio being able to speak to them via the link.

Maybe i'm best just to grin and bear it, and run the 8way multicore to join departments...

[Mowens800]

I'd just record it seperate. Have the band play, the presenter chat to them inbetween and all mixed and recorded live by the enginners straight to stereo with no post-edits, then broadcast it.

[benniferj]

I should have put that this isn't an option... I have to have live streaming from the Music Department into the radio studio. Its a requirement!

[grab]

Re latency, if the band are playing live, they don't need to hear what's being recorded. So the latency can be as high as you like - a couple of seconds would be perfectly adequate. It'd be a pretty poor sort of uni network that couldn't manage a sustained 350KBaud (4 bytes/sample times 44.1ksamples/s times 2 channels) transmission with that kind of latency.

You do need to be able to talk to the band, and have a minimal gap between the presenter saying something and the band responding. Voice quality isn't such a big deal though, so there's no reason you couldn't do this with any VOIP setup. You could keep the full-quality link if you wanted, or switch it to VOIP during the interval. But for the interviewer's voice being sent to the band, that can be VOIP all the way.

[muzines]

If you have Macs, then the first thing to try, given that you already have it, is Apple's AUNetSend and AUNetReceive plugins to stream a stereo signal over a network.

That will let you test the performance and see whether you think something like this could be workable for your situation.

If you find the performance unrealiable, or the latency to difficult to deal with for your situation, then I doubt *any* software network solution is going to give you the performance you need.

[benniferj]

Thanks Desmond! The Aunetsend/netreceive solution works perfectly. We tested that and found it had negligable latency. I started playing a track at one end, was on the phone to the guy at the other end and hit play, and it almost instantaneously started at the other end. Set up 2 stereo pairs going each way, so 2 high quality mixdown lines, plus stereo talkback and it works fine. So we're going to run with that, with a dedicated machine at each end doing the sending and receiving.

Cheers for the input!

[muzines]

Great!

[Aftertouch]

Very good idea, but I would still recommend as I did in my earlier post that you get the IT dept to set up a VLAN with QoS (Quality of Service) so that the traffic between the two Macs are not interrupted. This is useually a pretty straightforward process.

It may be that it works now, but the timing of the actual transmissions could have a detrimental effect on the live broadcast.

For example, time it to coincide with a popular time when students and staff log on and you could be stuffed!

[benniferj]

The computers in question are already on the 'music' VLAN, and they are going live during early evening, when general network traffic will be minimal, and certainly they will be the only users on the music VLAN as i'll simply lock everyone out of the logic editing suite given the radio station's priority. So hopefully it'll all work out ok!

[Aftertouch]

Perfect!

Sounds like an interesting project!!!

[benniferj]

I was just thinking 'when the station is live on air, i'll post the link to the station's live web stream'.

Could be interesting to see the hit on network performance when the station is broadcasting live to net at the same time. This needs some testing! Although I think the streaming server has to sit on a different VLAN so that should help a bit.

[Aftertouch]

Yeah, do that - would be worth a listen.

[Jeraldo]

Was digital transmission via phone lines considered?

I'm completely unversed in this whole area, so sorry if this is an obvious question/answer.

And thanks to desmond from this Mac user.