Do I *have* to Use DMX Cables?

First I'd like to thank Gavin Schafer for the photo... You can see his Flickr feed here.

The Question:

I run into this question a lot at work-

"Do I have to use DMX cables, or can I just use mic cable."

The short answer to the question is, "Yes, but I don't recommend it." So, that being said- there's a few things that we need to know about DMX cables and what makes them so special. I'm not going to go into a lot of super-technical detail here, but instead give a broader overview.

A Little Background:

First DMX, or more technically correct DMX-512 is a data communication standard developed by the United States Institute for Theatre Technology- USITTIt is designed so that lighting equipment manufacturer's equipment can communicate with each other.

An example might be- an Avolite controller, can control a dimmer made by Leviton, or a moving-head light made by Martin.  A Martin controller can control lights made by Martin, Robe, Chauvet, or anybody- as long as they're all using the DMX-512 standard. It's just like if I were to decide to hold a global summit in London this afternoon, I would hope that we all speak English so we can all understand each other and accomplish our objective goals.  In this particular example the delegation speaking Latin is not going to work well with the rest of us.

A second notable fact is that the DMX-512 standard dictates that we should be using 5-pin connectors on our DMX-512 cables. This was decided a long long time ago.(like in the 80's when big hair and spandex were cool.) By using a 5-pin connector, it prevents someone, say,  David Lee Roth from plugging his mic into the lighting rig. This means that according to the standard set forth by USITT, a DMX Cable terminated with 3-pin connectors is *technically* -NOT- a DMX cable. Some manufacturers, especially of lower end gear, just started using 3-pin because it was cheaper and 3-pin cables are everywhere.

Finally there is a specific amount of impedance in a DMX-512 control system. Impedance is the opposition to the flow of current in an alternating current circuit. In this particular case, the standard states that it should be 120 ohms.  Why this matters is that the DMX cables are  carrying digital data.   The streams of DMX data are carried down the cable in extremely short burst called packets. (think little suitcases of information with tags on them saying what airport they're traveling to etc.) I may not be totally 100% explaining this technically correct, but if the impedance is not correct it can create a scenario where there are packet reflections.   This can cause lights to behave erratically, or spazz out.  What happens when you're flying to San Francisco and your suitcase ends up in Detroit? Or think about what happens when you try to tell somebody something across an empty gymnasium.  The echoes of your voice blur the clarity of what you're trying to say and make it difficult to communicate.

Some Answers:

I don't really care about the whole 3-pin vs 5-pin debate. Lighting gear using 3-pin connectors is here to stay. So why use DMX cable? In production world- time is money. If I can take a step early on that will eliminate headaches in the long run, I will. Why waste time at a gig trying to figure out why light number five is strobing, and why light 8 won't do anything.  This means making sure I have the best data path for my controller to communicate with the lights. In fact we have a line of very inexpensive mic cables that we sell at work. I've noticed that these cables absolutely will-not pass data when used in a lighting rig. If I know all of my cables are good, then I've probably just addressed something wrong, or programmed something wrong on the controller.

~Andy

Lighting Control: How to Get More Bang for your Buck..

This is going to be a bit of a longer post, but there's a bit to cover.  A little while ago a person identifying himself  as  StevieWonder posted the following comment on one of my posts:

"Also wondered if you have any recommendations on controlling dmx with software and an ios device or a cheap netbook, or if a standard controller would do the trick? Any advice you can give would be much appreciated!"

This immediately raised one question in my mind. How does Stevie Wonder program lights?

The Dilemma

Until very recently, complex lighting control wasn't very affordable. Even super basic fader controllers to use with a basic dimming system were still around  $900 once you figure in sales tax for 24/48 channels.  They won't control movers well and still use microplex-  which is an archaic control protocol. (Although when looking at what ArtNet and RDM are bringing to the table DMX is archaic too.  All of this is a discussion for another day)

So then we take a look at the basic controllers like the Chauvet Obey Series, or the Elation/American DJ DMX Operator series.  They're great if you only have say 12 different fixture types, and are maybe recalling movement macros, or color macros on your lights. You're probably not going to program the Kiss reunion tour on one of these. I feel like it would be similar to hanging drywall with a screwdriver.  You can do it. But it's going to take a lot of effort.

The Solution

I'm about to say something really crazy. This is especially insane considering over a year ago I posted this blog about choosing a computer for recording- Recording from Your Digital Console: Choosing a Computer. The most cost-effective way to get a lot of features in a lighting control system for not very much money is to buy a touch screen tablet PC running Windows 8.

Many of the current lighting control software options offer remote control via iPad, iTouch, iPhones, and some Android devices, but you have to have a computer to host the main part of the program. Why not just skip a step and buy a touch screen tablet? It will be cheaper than buying a desktop/laptop machine and an iPad. There are some great deals on new and refurbished units out there. You just have to shop around. New Egg and Tiger Direct are two great places to start looking. (Unless we happen to start carrying tablets at work- at which point I'll edit this post and add a link.  Yes, I know shameless plug, but I gotta buy gear too. And eat.  Bacon ain't as cheap as it used to be.)

The Software

For lighting control software there are two main titles I would look at.  One is the Avolites Titan One dongle. The other is Chauvet's Show Xpress. Conveniently, we carry both of these at SE Systems. I'm only going to highlight a few features of each right now. I'll probably go a little more in depth later.

Avolites Titan One

This. Is. My. New favorite thing! The Avolites Titan one dongle has quite a few advantages working for it.  The first is that it's the same software that all of the Avolites lighting desks use. The Titan One all the way up to their Sapphire Touch use the same exact software. This means if you learn how to use one, you can use them all. Here's a few other advantages:

1. Price Point- the retail price of this package is only $250.00 USD. You have to be kidding me! Pro level lighting control for less than $300. (OK well you still have to have a computer but still)
2. Cue Stacking- This is a great feature that allows you to take multiple cues, and assign them to one fader. For example, say you have a look programmed for your house lights, a look for your upstage (back wall) uplighting, and a look for your stage/front lighting. You might have a volunteer running the console, or you may just want to be able to touch one fader to have all three of those things change at one time.  You can do that.
3. Avo's Quicksketch-  This feature lets you quickly assign a picture or scribble your own to assign to buttons and faders. So you can have a picture that means something to you. Like a guitar for a guitar solo look. Or a picture of Bob if Bob is speaking this week. Or a big red button for your big red look. Or a smiley face with a big hat when the band covers "Happy."
4. Pallets, Shapes and Pixel Mapper effects-  These are tools that allow you to build shows quickly and efficiently- Think of pallets as collections of attributes.  I have a box of colors. I have a box of moving light positions and movement patterns. I have a box of chases and color changes that I can draw from.  Then I can take these attributes, select the ones I want and place them in a cue or cue stack.
5. YouTube- There are a lot of YouTube training videos linked on Avolites' website, or you can just look for Avolites' YouTube channel.
6. The Manual- There is a very detailed manual available for this software that goes over each of the features.

Chauvet's Show Express

I've probably spent more time using this particular software than the Avolites. Part of that is that the Avo software hasn't been available quite as long. (At least not at work.) Here's a few things I like about it:

1. Live Mode: This basically gives you a panel of buttons that you can use to trigger scenes or looks. Very simple interface for a beginning user or volunteer operator. Live mode can also be remotely operated via an iPhone or Android based app. (But if you're running on a Windows 8 machine, there's no need to. Unless you want multiple pages of scene triggers- which might be super handy.)
2. You can trigger multiple scenes in different windows of live mode. So if you have your uplighting blue, and your stage lighting green- as long as you have those scenes saved separately, you can recall them individually, but at the same time.
3. Start in Live Mode:  You can actually set the software to start up in "Live" mode so that the operator doesn't have to deal with the set up or programming options.

So this is just a super basic overview of two systems. I may write a more detailed write up of each system in the future.

~Andy

Ghost in the Machine: Me Vs. a Dante Network

A few months ago, I think it was early March, I went to help a church get some problems with their Dante audio network sorted out.  (Yes, I need to write more often- don't worry,  Mom says the same thing.) They currently have a Yamaha M7CL with two Dante-MY16-AUD cards connected to a Cisco switch, which is connected to another switch in their production room. The two Dante cards handle 16 channels of audio each, so that they can get all 32 channels to their recording room. Their production machine is a Mac Pro running Apple's Logic software.

In full disclosure, let me make the following statements:

1. I should have payed more attention in NET 125 Networking Basics. But the material was super dry and let's face it.  That's not the sexy side of playing with all of this awesome audio gear. Am I right?
2. I know people that have fairly complex Dante networks that are working beautifully. For example there is a local college that is cramming audio through their regular infrastructure. Meaning there are multi-channel strings of audio swimming in the same stream with college students streaming Downton Abbey, The Walking Dead, Mad Men, Breaking Bad and Walker Texas Ranger. It works.
3. Dante works beautifully, and is almost completely "plug and play" on consoles that run Dante natively (that don't need an expansion card) like Yamaha's new CL series consoles and Rio stageboxes.
4. I typically dislike thing that take a lot of effort to set up. Let me get to what I came to do as quickly as possible. Which is usually mixing.

The Problem

In this particular case, the problem was that the same audio data would show up on channel 1 & 17, 2 & 18, 3 & 19 and so on inside Logic.

So I went through a few quick trouble shooting steps:

1. I looked at the direct output routing on the M7CL. Everything was patched one to one just as it should be.  Direct Out 1 was patched to Card Slot 2, Output 1-  Direct Out 2 was patched to Card Slot 2 Output 2. (the Dante Cards were in slots 2 & 3) That was all good.
2. I looked at the matrix in Dante Controller on the Mac. Again everything was patched beautifully.
3. I looked at the patching in Logic. 1 to 1, 2 to 2.

In theory, everything should work beautifully. It was time to dig deeper. We fired up Dante Controller on the Mac and took a look at the device info and network status.  This is where things got crazy.

Both of the Dante-MY16-AUD showed up in the device list, but only one had an IP address.  So we unplugged the cards one at a time from the network and each one showed up just fine. Then we plugged the second card in. The network assigned the second card the same IP address. That *might* explain the duplicated audio.

We took a quick look at Yamaha's and Audinate's (Dante's parent company) websites to see what the current firmware versions for the Dante Cards, and software.  We were a few versions behind. So we went through the process of updating Dante Virtual Soundcard the production machine, and my laptop, Dante Controller, and the cards in the M7.

We connected everything back up- aaaannnnd....(insert drum roll here) problem not solved. We were still getting duplicate data. If we manually assigned IP address one card wouldn't show up.  It was 3:30 in the afternoon. I had been at the church since 9:30. I had exhausted all of my options except one. Update the firmware on the M7CL. Unfortunately the church had a big production coming up and didn't want to do that and risk losing all of their scene data. I had to concede defeat and return home.

~Andy

2014: A Few Things I'm Excited About

I pay my bills by working at SE Systems in Greensboro, NC. It's a pretty cool place to work, especially if you're an audio geek. Not only are we a live events production company, and a pro audio, recording and lighting sales company, but we also have an on-site class/presentation room. We are going to be utilizing that room a lot this spring! I'm excited about that.

Rational Acoustics Smaart Training:

On February 25-27th, 2014, Jamie Anderson from Rational Acoustics- makers of Smaart- audio and acoustic measurement software- will be at SE Systems teaching users how to utilize the software. You can register here: http://www.rationalacoustics.com/events/greensboro-nc/

Smaart is amazing software. In short it allows you to "see" the sound. You can look at the frequency response audio systems. You can look at the reverb time in a room. You can look at the phase correlation between two different audio sources. There's really a lot you can do.

Worship Technology Information & Education Series

This spring we're offering a series of classes for all of the volunteer audio folks out there. Sound techs, sound person, techie, sound guy, A/V tech, worship leader- whatever this person is called at the church- this is for the person that wants/needs to know a little bit more.  Here's the basic layout:

Feb 15:

Audio Mixing and Multitracking.

March 15:

Worship Band Monitor Mixing and Personal Monitor Mixer Techniques.

March 22:

Loudspeakers, Wedge Monitors and Open Architecture Signal Processors.

April 19:

Microphone Techniques.

I hope to have more details soon. In the mean time you can keep an eye on www.sesystems.com

~Andy