New Lighting Desk

[frost]

Hi,

 

I work in a youth theatre and our lighting desk is a bit doggy, sometimes it will work and sometimes it won't. We have also had a problem where it has cut out in the middle of a show.

 

We are looking to replace it but we don't really have a budget to get one, so can you recommend any cheapish desks - but ones that won't stop working after a year or so. The desk will need to control:

 

1 x Martin Mini Mac Profile

4 x Martin CX-4

and about 15 parcans

 

Is there anything that you could suggest?

 

As I said I we don't really have a budget, so the cheaper the better - but no to cheap that it will only last 6 months

 

Thanks

 

Toby

[Mr Steve]

If you have no budget, or something minimal, then I'd sell the Mini Mac and add the funds from that towards the new desk. One mover isn't much use anyway.

 

Not sure what to suggest desk wise, if you have no money - perhaps something 2nd hand. I assume you'll need something with memories if you intend to use the CX-4s on it, which will bump up the price.

[BlueShift]

well my first instinct is a fat frog - its perhaps more than you need, but is the staple of many youth and amdram theatres everywhere - they are very reliable and built like tanks. Not the greatest desks out there but good for the money. One of those will set you back around £1500

 

however I fear this maybe out of your budget...

[back_ache]

but we don't really have a budget to get one

 

I'm probably going to get flamed for this,

 

* get someone to give you a PC(dosn't need to be anything special), reinstall windows and ban anyone from installing anything or connecting to the internet.

* spend 40 quid on an open DMX interface for it.

* install one of the free desk software that are around.

 

http://www.enttec.com/opendmxusb.php

 

As well as the cost saving you have the advantage of using different desk software for different gigs, so for one a simple A-B desk, another a fully featured memory desk and for another a sophisticated sound to light.

[benweblight]

why not get the old desk fixed?

 

would probably work out cheaper

[jfitzpat]

but we don't really have a budget to get one

 

I'm probably going to get flamed for this,

 

* get someone to give you a PC(dosn't need to be anything special), reinstall windows and ban anyone from installing anything or connecting to the internet.

* spend 40 quid on an open DMX interface for it.

* install one of the free desk software that are around.

 

http://www.enttec.com/opendmxusb.php

 

As well as the cost saving you have the advantage of using different desk software for different gigs, so for one a simple A-B desk, another a fully featured memory desk and for another a sophisticated sound to light.

 

The 'flaming' is going to come from a strange quarter, since we do PC based control, but I'm not sure that this approach accomplishes anything at all. Sure it is cheap, but it seems like the basic problem isn't capability, but reliability.

 

I can personally attest that you can buy a $300 computer and run a 7 universe show 15 times a day, 7 days a week, for two years without a problem. But a hand-me-down computer running freeware which, in turn, is relying on the Windows COM stack and a slightly buggy FTDI driver (last time I checked it still did not handle power management IRPs correctly)? I have serious doubts.

 

I don't mean to sound like I'm down on the whole 'open DMX' initiative. In fact, we've assisted a couple of vendors we work with in getting the Enttec stuff working reasonably well. Some of our fixes have even found there way back to the 'community'. But what can be great for the do-it-yourself hobbyist is not always so hot for someone who is more end result centric. For example, saving $100 in exchange for sometimes crashing when you click on the name portion of a fixture icon to select it (I don't mean to pick on FreeStyler, it is a pretty impressive hobbiest clone, it was just the first one to come to mind) is fine if lighting is a shoestring hobby. It may not be such a great trade if show failures are your reason to look for new gear in the first place.

 

I also am not sure I buy into your 'specialized software for specialized shows' argument. Again, this might be great fun for the hobbiest, but in pro and semi pro work learning curve and operator training are pretty big issues. I would think that for most shows they would far outweigh any benefits from show type specific features.

 

However, I do think that show type is a concern. Most PC offerings do a pretty dismal job of on the fly live control without add-on tactile surfaces. We did an additional screen which is really a full application in its own right for precisely this purpose. Still, we always include a DMX-in so you can use an existing small console as a tactile surface and support for external MIDI controllers (lower resolution faders, but helpful for the budget sensitive). Sometimes, you really want knobs and switches. If you start factoring this sort of functionality into an OpenDMX based rig, your savings shrinks and reliability also suffers (most vendors report lost packets/bad packets even when using a dedicated thread at elevated priority with the OpenDMX input).

 

Again, I think that an OpenDMX initiative is worthwhile, I just wonder if it is really suitable in this case - especially with a small rig and existing reliability problem.

 

-jjf

[back_ache]

:o

The 'flaming' is going to come from a strange quarter, since we do PC based control

I feel well and truly barbequed :(

 

I have no doubt that PC are ready for show control as I am a computer/network technician as well as a theatre/AV technician and know first hand their strength and weaknesses.

 

My local theatre use a PC based solution (via an ethernet interface) with (say it in hushed tones) distributed dimming and has no more problems than you would have with a conventional desk.

 

I'm actually glad to read warts and all reviews on things, so maybe opendmx isn't the way to go but your door might be one he could knock on for a commercial PC based solution.

[Tomo]

An ethernet interface is very different from the Enttec Open-USB interface, and is fundamentally more reliable.

 

For a start, the Enttec relies entirely on the PC for break, packet and frame timing. The only thing provided by the interface is a serial output at a guaranteed baud rate. So the host PC is required to dedicate a rather large amount of processing time to the business of generating DMX packets.

 

An ethernet system uses local, dedicated processing to convert a set of levels (512 bytes of data) into properly timed packets, and can thus guarantee individual packet timing - although break timing depends on implementation.

 

While both methods rely on the host PC to generate updates to the DMX data, the OpenDMX puts the onus on the PC for good packet timing and is thus much more sensitive to issues with the host PC.

 

Ethernet also uses well tested drivers that are part of the OS as it is simply an ethernet packet stream created by the console software at a relatively high level. The majority of ethernet issues would be to do with the software in the Ethernet -> DMX unit, or poorly specified transmission standards (ART-Net apparently doesn't play nice with other items on the same network).

 

The OpenUSB devices rely on proprietry drivers provided by FTDI, which are fairly good but not as extensively tested.

 

Finally, a PC running Windows, OS-X or Linux is not a real-time device, and has no guarantees that given processes will run at a particular rate.

While real-time operating systems exist that run on PC hardware, they are expensive and would be found in 'proper' consoles.

Usually the RTOS drives the DMX engine, with Windows or Linux running the user interface.

[jfitzpat]

I feel well and truly barbequed :o

 

I didn't mean it to be at all personal, sorry if it came across that way.

 

As far as reliability, I think that a properly developed PC based solution should be more reliable that a complex console. Just from a manufacturing/quality assurance point of view. Although it is dangerous to read too much into a small statistical sampling, I've always found it interesting that of the three units we've shipped to the UK for review, two were rushed into actual service by the reviewers because of a name brand desk failure.

 

As far as RTOS, etc., I think Tomo would be surprised at how many big name consoles use desktop OS threads for data generation. Most, like us and unlike the Enttec OpenDMX, offload DMX transmission and framing. So packets are sent and resent as fast as the standard allows. But most still do not generate new DMX data all that quickly. As I've mentioned in other topics, our data update rate is 30 Hz under stress conditions (we felt that video/media stuff was continue to get bigger). It did take some effort to make sure that update rate occurs even if a user decides to launch WinAmp or use WMP to view, uh, 'documentaries on interpersonal relationships' from the Internet, but the work mostly resolves around latency, not raw computational power. Even with 16 universes full of fixtures updating at 30 Hz, it still isn't that much data on a modern CPU.

 

Still, if you look at many top end desks with a DMX recorder you can see that their update rates fluctuate under various conditions. Since they are already updating slower to begin with (20-24 Hz) I suspect that they don't go to the extra effort to elevate some tasks out of normal application status and, instead, rely on not allowing web surfing, etc., to keep things responsive under stress.

 

-jjf

[dbuckley]

To add my 2c to the pot: The issue is cheap hardware and free software. PCs can do a rock solid job of lighting control, but I've yet to see a minimalist cost initiative that does so. The nearest is probably MagicQ that is free, and runs with the Entec interface. Its the proper desk software, but essentially mainly intended as a editor / training aid for their "proper" desks.

 

Many folks herabouts seem to be of the opinion that a PC lighting solution is a cheap and nasty solution for people who cant afford a proper lighting desk, that simply ain't the truth. It is true there are many cr*ppy solutions out there, but that doesnt mean that all solutions involving a PC are cr*p.