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DIY IP show relay


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I'm working on a show which where we need to install some show relay using the venue's wired ethernet IP network and a bunch of mac minis, so looking for ideas about how best to arrange an audio only audio stream from a show relay mic.




two separate output feeds in different dressing rooms

stable (eg would auto-reconnect in the even of a network glitch)

free/low cost software on each mac.

latency of up to 1-2 seconds not a huge concern as both locations are far away from the performance area but obviously don't want huge lag as it's being used for cueing


Won't really know how the network performs until we try it, should assume that it's reasonable stable but may not be gigabit.


One suggestion has been NDI tools on both sides, but that involves sending a video feed as well, so much higher bandwidth just to send a black screen.


I know VLC has some built in stream source functionality, has anyone used that in show conditions?


Any other ideas?



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Bunch of Mac minis sounds expensive; I'm guessing you already have them,


If I was building it from scratch, on a budget, I'd be looking at a bunch of Raspberry Pis, running your favourite Pi linux distro. One will need an audio "hat" to give decent inputs. Software is base Linux, plus Darkice, plus Icecast server.


The listening ends are similar Pis, Don't need Darkice or Icecast - just tell them to run mplayer http://source.ip.address:8000 on start-up.


But that's me, and I like those sort of projects.


Other option, using your minis - find something to run Icecast on - it'll run on Linux or Windows. Do your encoding on one of the Mac minis - use something like "Butt", which is free. Tell that to send the stream to ice cast, and use your favourite media player on the other minis to listen. Keep the bandwidth reasonably high and buffers small, and you'll have low latency.


You don't need gigabit.

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I'm working on a show which where we need to install some show relay using the venue's wired ethernet IP network and a bunch of mac minis, so looking for ideas about how best to arrange an audio only audio stream from a show relay mic.


macOS has this functionality built in terms of the AUNetSend and AUNetReceive audio unit plugins. All you need is something capable of hosting them. You might be able to cook something up using the free version of QLab but I've never tried doing anything like this.


Reaper can probably also do it but it's not free. Other ways of doing it that are not free would be buying Dante Virtual soundcard and doing the routing using a DAW like reaper again or can probably do it just with Dante Via.


Words of warning though successful audio over Ethernet needs a relatively high quality network and Dante in particular has same QoS requirements. I would not trust my show to an unknown network.


If you can it would be far better to just unplug the patch from the switches and use baluns to send balanced analogue audio down the cable instead. I appreciate the venue might not let you do this.


I'm somewhat curious as to what this venue is now...

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Consider MTBF


If the venue has CAT wiring then adapters and analogue will be less trouble in the long run. Maybe need local amplification as 100V line (can get above 100V) is pushing insulation near the limit.


This is definitely the easiest way if you are able to isolate it from the IP switches, mic, pre-amp, 2 Fosteks and possibly isolating transformers. I do this every year in 3 venues with video too.
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We build a system with Raspberry Pis that was basically XLR in at one end, out at the other with Analogue XLR in and out.

In the end we abandoned it as it was a pain in the arse.


It isn't a very helpful comment we are looking to replace with Dante AOIP-22 or similar cheaper eg





If I was rigging it for a temp system and the network had reliable web access I'd seriously consider just using a unlisted youtube live stream on low latency without video. Using OBS you could encode an audio stream at the input end and each output would only need a browser so could just be a phone rather than Mac mini. You'd need to set it off every night before show but it's zero cost.


The other suggestion if you can actually get to the patch panel in the venue and there's copper point to point is also the simplest way, just make up some rj45 - XLR adapters. If you actually need to run over IP and there's fibre or a wireless bridge involved or via multiple switches then you'd a bit stuffed for that one.

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  • 2 weeks later...

Hi all, thanks for all the suggestions and sorry for not replying sooner - went into full on production mode. VLC worked well in the end - aside from the fact that the UI is terrible, and has no way of saving capture/streaming presets that I could find! But it can create an Ogg audio stream and serve it over http with no bother to a couple of other VLC clients.


To round off the other suggestions/issues - yeah, Mac Minis were overkills, but they were what I had available :) No chance of using analogue audio on this, it was a staff network in an educational setting across several buildings and getting access to the network at all required a favour.

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You cannot save streaming presets - but pretty much everything you can do through the UI you can do through the command line (including, with some futzing, watching the video rendered in ascii art) - and if you can do it through the command line, you can make either a shortcut or batch script to automate it - both at the receiving end and the serving end - it is what makes VLC awesome, as you can trigger starting and stopping streams - as well as opening streamings using an SSH connection into the clients. Edited by mac.calder
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