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DMX installation at OnAir Solutions

DMX lighting control for corporate video studios

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DMX512 is a Digital MultipleX of data values, most commonly used for lighting and related control in live performances, video studios and theatre.

Why DMX?

In a world where we have so many standards, DMX is one of the few universally accepted protocols, appearing on fixtures and control systems used in any professional lighting application. Of course, there are some variations in pinouts/connectors (despite the standard) and the quality of the decoders can vary.

DMX is mostly commonly used for dimming, but in live shows is also used for colour, position, and other effect control. Once upon a time, a large rack of DMX-controlled dimmer racks would be hidden off-stage, but with the move to smart fixtures and LED, most lights have DMX control on-board.

For all the gory details, Wikipedia has a good backgrounder, and there are many good reference sites.

DMX in a corporate video studio

For corporate video, it is tempting to skip lighting control and just use standard office light wiring, or a building control system like C-BUS or DALI. This will often work OK, but it means setting dimmer values at the fixture rather and having no control other than on/off. This means and adjustments have to be made at the fixture, which may involve step ladders and safety concerns if staff aren’t experienced.

If you are using a green screen, or a changing environment like a radio studio, we recommend going with a DMX system. The investment is surprisingly small and you will get a lot more control and flexibility. Precise dimming control helps balance the lighting levels in your studio, and we can’t stress enough how useful this if for green-screen work.

Most fixtures designed for studio lighting will include a DMX option, and many include it as standard. You just need to make sure the fixture will actually dim smoothly, particularly if you plan any lighting changes during live work.

Hardware to talk DMX is very cost-effective, and if your needs are simple the software is free. Read on for our DMX tips.

How OnAir Solutions tackled DMX

DMX connector

When we built our own demo green-screen TriCaster studio in our Sydney showroom, we wanted to include DMX to show easy it can be.

We started with the Jands JLX-Lite lighting bar. Available in white, black and custom colours – the JLX-Lite comes in 1600mm and 2400mm lengths. It includes 4 or 6 Australian/NZ mains sockets and space to install DMX chassis connectors. We have two bars and wired the DMX in a daisy-chain to each, because our needs are pretty simple.

We then added the ENTTEC ODE Mk2 Ethernet DMX gateway. This connects on your network, powered by PoE, and provides a high-quality DMX output.

Open DMX Ethernet Mk2 installed at OnAir Solutions

Finally, you need some software. We’re assuming that for corporate video you don’t want or need a hardware lighting console. If you do, there is ample choice from budget to high-end. But for us, a simple software solution was all we needed.

The good news is QLC+ is available for Windows, Mac & Linux (inc Raspberry Pi) for free. It’s pretty simple to setup and is well-documented. Its actually pretty powerful software and is widely used.

QLC+ fixtures page

Troubleshooting

Like any communication protocol, there will be times DMX doesn’t behave like you expect. Common problems are no communication, address clashes and flickering lights.

There’s countless tutorials you can find, but here’s our hit-list of things to check:

  1. Cable – you need to use suitable cable, not mic or analogue audio cable. We often use Belden 1800B, it’s great for AES audio, Analog Audio and DMX, and means we don’t have to keep as many types of cable in stock. It needs to be a twisted-pair for noise rejection, and the right impedance, especially for the longer runs.
  2. Earthing – like with audio, earth loops can sometimes be an issue. Best pratice is to earth the cable drain wire at one end only (eg the DMX origin point), and lift the earth at the other end. Unlike audio, this can be harder to manage as your daisy-chain cables would normally carry the earth through. So its probably best to ask for advice before doing this.
  3. Connectors – any compliant fixture should have a 5-pin XLR for DMX. But because DMX normally only uses a balanced data pair plus signal ground, it is still common to see 3-pin XLRs used. In a fixed install it is easy to standardise, but in the field you normally need some adaptors handy. Make sure pin 2 goes to 2 and 3 to 3. A swap between 2 and 3 somewhere in your chain will definitely cause problems.
  4. Termination – as DMX is a transmission line, it needs termination at the end. This is usually a 5-pin XLR with a 120ohm resistor. Some fixtures will do this with a switch, and some claim to do it automatically. Our advice is find out, and be ready to put a DMX terminator on the end of the line. It helps stop reflections in the signal, and becomes very important in a long chain or with a lot of DMX data (many fixtures).

We recently had to troubleshoot a DMX install used in a landscape lighting installation. Because one cable had to run in a conduit near a power conduit, the system was picking up noise and flickering once many simultaneous lights were on. We also suspect some of the garden LED dimmers and directly controlled fixtures weren’t playing nicely. This is common in the DMX world, so you sometimes need to play around to find a solution. The combination of lifting the signal earth one end, and an ENTTEC D-Split for isolation got the system fully stable.

Find out more

If you’re building a corporate video studio or need assistance with DMX solutions, please get in touch with us at OnAir Solutions. We have the full ENTTEC catalogue available on our webstore, with some items, in Sydney stock.

We can also assist with any of the Jands catalogue of lighting equipment, including lighting bars, control consoles and fixtures. If you’d like to see it all in operation, email us to book a time in our demo green-screen studio in Sydney… we’d be happy to show you through it all.

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Green Screen studio

Green Screen lighting for TriCaster

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Green screen “keying” is becoming very popular in small studios and corporate video facilities. Using a process known as “chroma keying” you can place your host and guests in a virtual studio or in front of a live background, making a very professional video. Television studios and film have always used green and blue screens for both effects and everyday shots. Until recent years, the costs of doing this in a corporate environment were prohibitive.

NewTek TriCaster – virtual sets

Since the first all-digital versions of the NewTek TriCaster, doing green-screen virtual studio work finally became affordable for small studios. The TriCaster has all the tools for chroma key built-in and produces excellent results.

It does take more effort than just pointing a handycam – lighting, camera quality and the screen type/material all come into play. You’ll also find your camera angles become restricted by how much green screen is visible behind – so tights shots are much easier than a wide angle.

But with virtual sets in the TriCaster, you can still give the appearance of a very big studio in quite a small physical space… that’s the power of virtual sets.

How do I light a green screen?

This is easier said than done. With a big budget, you can put in lots of lights and achieve a very even coverage. Best practice is to light the screen from top and bottom at a 45 degree angle. The lights should ideally be placed at a distance equal to half the height of the screen – but this is not always possible in a corporate studio.

Low ceilings and small rooms are the norm, and this is exactly the challenge we faced in lighting our own green screen in our demo studio. The other challenge is getting enough distance from your hosts to the back of the room where the screen is – too close and you’ll get a lot of difficult shadows that make “pulling a good key” much harder.

Thankfully, the cost of LED lights has come down a long way in recent years, so its practical to install a small number of quiet cost-effective LED lights. This avoids the hassles of flouros or power consumption of tungsten bulbs.

The purists may not agree, but remember this is about cost-effective solutions for corporate video… not 4K movies.

Chroma-Q

In our studio, we have chosen the Chroma-Q range. They aren’t the cheapest option on the market, but the wide spread of very soft light means we can reduce the number of lights required, and we’ll get good results from just two overhead fixtures. For wider shots, we may supplement that with some small floor or side lights, but in our testing so far, the TriCaster is producing very good results.

The Chroma-Q Studio Force D12 is designed specifically for lighting green screens and comes in 5600K daylight colour temperature.

Colour temp is another minefield and we’ll spare you all the gory details. We chose daylight as we have some outdoor light spill into our room, so its the most forgiving in that situation. Again, the purists may not love it, but we need to keep things practical.

Chroma-Q Studio Force D12

Green Screen options

The solutions here depend a lot on how much space you have and what kind of shots you need to do. If you need a portable solution. a backdrop cloth with stands is the way to do.

If you need to do full length shots (head-to-toe), then you need a screen that the host can stand on, and has a nice curve to avoid any dark spots in the corners. This kind of solution can be done, but is harder to achieve than just a simple backdrop.

You can also do ceiling rails with green backdrop curtains, which are commonly used in larger multi-purpose studios.

For our demo studio, we went the simple option of painting the wall. But don’t think you can use any green paint – you still need a paint colour designed for this task, and will often need a lot of coats to get even coverage. So it will still cost quite a bit more than painting a standard home or office wall would.

Why Green?

The short answer is that people wear blue colours more than green, so there is less chance of having a problem with clothing. The longer answer also involves some of the historical video processing techniques in analog and digital TV. If you are interested you can read more on Wikipedia.

How does it look?

Stay tuned… in one of our next posts we’ll be testing things out on a NewTek NDI enabled PTZ camera, and putting it up against some other cameras. We’ll post the results so you can be the judge. We’ll also be going into more detail on lighting bars and DMX control options – showing you a variety of options from basic to more advanced.

Further advice and where to buy

Chroma-Q is a new addition to our range and will be available online soon. In the meantime, please see our Chroma-Q product page.

NewTek TriCasters are available directly from our webstore. We also hire our TriCaster Mini HDMI and TriCaster 8000 for events – see our rental page for more info.

NewTek have a great article on their site that goes into a lot more detail on how to light and shoot a green screen – see here.

For the screens themselves, we recommend you give us a call or Email to discuss your options. We have a range to choose from, and can make sure we get the best option for your requirement and budget.

If you’d like to see it all in action, please come visit us in our Sydney demo studio and we’d be happy to show your some different solutions and what it all looks like.

About OnAir Solutions

OnAir Solutions is an Australian company formed in 2010 to provide audio and video solutions for broadcasters, web streaming and corporate marketing. We have 12 staff based in our Sydney office and supply a range of solutions from leading international and Australian manufacturers. We also do cabling, rack builds and studio installation around Australia.


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