Backstage Monitors - Video and Audio

[Ian_P]

Hi all,

I have an opportunity to set up a backstage monitoring system, to take over from the damp string and bean can set up I have now. Audio in the dressing rooom is fed from a 'Archer' battery intercom with the transmit button screwed down, feeding into the music on hold port of a Nortel PABX, so the dressing room phone can select this feed. It's not very loud, buzzes when the stage lamps dim and is a bit tinny. No video.

The side of stage wings TV monitor is a 14inch portable CRT type TV fed from a old webcam. All works, but is very poor video quality.

I would like the system to start with 2 screens but be able to expand to 4 or 5 in the future. Could the speakers in the TV screens be the recieved audio?

I need audio in the dressing room only, but availability elsewhere would be nice. I would imagine HDMI cables would be the way to connect all this up, but as we don't have this yet, happy to consider better alternatives.

Given a clean sheet of paper, and being aware of the low cost of quality HDMI type screens available these days, can anyone suggest what would be the best approach? What equipment might I need? Video splitter, mic audio souce, input, pa etc?

We have just purchased a 42 inch screen for the dressing room, and a 32 for the side of stage monitor. Everything else is up for grabs.

 

Thanks

Ian

[sunray]

This is something I set-up quite often for shows.

In these temporary systems I have stayed with audio (usually off the main desk but sometimes a couple of mics on a Spirit notepad/ Behrenger 1202) and composite video for simplicity and reliability. I did use the TV speakers but like so many thing these days they need the remote control and too often it would get lost under a pile of props/clothes/makeup etc so now I install a powered speaker in each location, usually Canford/Fostek but PC powered speaker are pretty good too these days.

2 of the venues I do this in have Ethernet cabling in place and cheap CCTV devices work well for those. I've knocked-up a project box with a 2way VDA and an ethernet adapter plus audio isolation transformers to make it a really simple installation to 2 rooms.

I've seen hellishly complicated systems that take a read of the manual to get working, I've seen Raspberry PI's dedicated at each location, I've known software crash during shows...

In my view this is one area where less is more.

[Geoff49]

Do you have structured cabling (Cat5e/6)? We are using a cctv camera producing hdmi which feeds an Antiference hdmi0108scat unit which converts the source hdmi into a proprietary format and sends this down the cat6 (recommended) cables and then local RX units convert back to hdmi.

If you can get the audio into it by using an hdmi combiner then you can use the tv speakers as well, although our feeds are on separate LS.

[J Pearce]

I'd be doing the cabling on CAT5/6. Whether you then use baluns for analogue signals, use something like HDBaseT, or video over IP is for debate, but at least the cabling then gives you options.

Analogue video is very low latency, but looks pretty crap now that we're all used to HD video all day every day.

HDBaseT is nice, but not cheap. Generally pretty low latency.

Video over IP can be very cheap, and can sit over an existing network and provide other opportunities - but has has higher latency. Fine for dressing rooms/crew room, no good for wing monitors or DSM feed.

We do analogue composite video to DSM and Flys (DSM also gets a HD low latency feed via SDI). MD cams are all analogue at present for low latencty. Wing monitors are usally SDI, but would go composite for MD or IR camera. Then IP feed via a either RTSP or a webserver (running on a raspberry pi) for offices/stage door etc. We're looking to expand that to green room. 
Audio all goes via our paging system, though there is audio on the IP feed for anyone who is in a room that isn't on the paging system.

[richardash1981]

Basic comment I've not seen anyone else make is that standard HDMI cables work up to 5m length reliably, 10m sometimes. After that you get into actively boosted cables, or HDMI-over-fibre cables (neither cheap). Which is why J Pearce is asking about CATx cable (network cable) as once you get over the converter cost, you get much further with much less cost (and if the cable does get damaged, you keep the end equipment and run a new CATx cable).

[Ian_P]

Thanks all - the message I'm getting is to run CAT5 cables from the tech corner to all places I'll need video/audio. This I can do no problem.

Once that is done - I'm looking at an Antiference hdmi0108scat unit or similar (Thanks Geoff), which means I don't need local power for the convertor dongles.

One challenge I'm having is I've replaced the old compostite video camera with a new CCTV FHD camera - I was expecting this to work as the connectors are all the same - but it don't!

Is CCTV not compostite video anymore..? 

[musht]

Mention of FHD may mean AHD, composite isn't so popular nowadays https://videos.cctvcamerapros.com/surveillance-systems/what-is-ahd-cctv.html

[Stuart91]

1 hour ago, Ian_P said:

I've replaced the old compostite video camera with a new CCTV FHD camera - I was expecting this to work as the connectors are all the same - but it don't!

Is CCTV not compostite video anymore..? 

There are various CCTV standards (AHD, TVI and more) which can run full HD pictures down analogue cable. It's useful for retrofitting HD cameras to older installations, saves you having to run fresh cable. 

The connectors are the same BNCs as composite, but the signal is very different and incompatible. You can however get conversion boxes to HDMI (something like this) and some other models can produce composite if that's what you need. 

Might also be worth digging in the camera menu / settings as some are able to downgrade their output to composite SD. It's becoming rarer on newer models though. 

 

[Geoff49]

Ian_P: you're welcome. For that unit (and probably others) just make sure you install cat6 (minimum) and not cat5 or cat5e... and yes the remote RX take power from the cat cable - but they do have the dc-input socket is you find you need power at the end of a long run. Check it works, before you buy, if your runs are more than 40m, as the spec is 40m max. This is my first job to sort out - some displays are unreliable on this system, and I think its because the cabling is 'only' cat5e and run in close proximity to mains and everything else! Running some temporary cat6 tielines in free space and they have been rock-solid so far.

[Ian_P]

Just to complete this thread, I ran Cat6 cable, and purchased a Antiference 4 way splitter, but I coould not get it to work. It would flash the video up on the screnn for about a second then nothing. I tried local power to the baluns - same. Tried different displays, different inputs, different baluns (there were 4 in the box) - no joy. As the video does display for a moment I have to assume the splitter is at fault.

Gave up and ran a direct 30m HDMI cable which works perfectly.

Anyone want an Antiference Video spliter...?? ;0)

[Geoff49]

I would suggest checking the hdmi resolution of the camera and what the monitors will work with. I had to connect the camera to a ‘tv’ monitor first and set the resolution to suit the pc monitors. The camera was factory set to 1080p30 and the monitors would not see it; they wanted 1080p50 or 60, IIRC. Once I changed the camera output they have been ok for the shorter runs on cat5, the longer runs needed cat6 as previously mentioned.