In the UK, the standard for these things is http://www.canford.co.uk/STUDIO-ILLUMINATED-SIGNS the most popular version uses contact closure to make it light up avoiding mains power switching which can click or pop. Some people modify their desks to use an existing switch, while the radio people of course have switches in the faders. Few studios I've been in have anything automated, though - simply a button, often wired using 3 pin XLRs, so you can use a tie-line rather than a tricky re-wire.

One of the studios in which I attended a mastering session of a CD I had recorded had gone through a number of different illuminated "Recording" light schemes. They had slave lights in several places, such as each of the recording rooms, the artists' room and even (as a laugh) the gents toilet. The light switch scheme they ended up with was a purely hand-operated switch in the control room linked to the lights via a series of solid-state relays.

They said the reason for making the lights so conspicuous but uncoupling them from any mixing desk or transport controls was that they could capture the takes done when the artists didn't think they were being recorded. These sometimes turned out to be the killer take.

Yeah recording without the knowledge of artists is one of my guilty pleasures !!

Hey guys, thanks for the quick replies and pertinent experiences. I was leaning toward a simple AC switch/button by the console and based upon all your responses I think it will be my best solution. I have a separate clean power system for the recording equipment so I think I can isolate a dirty AC line to the desk without getting pops. So many details to this project really makes my head hurt at times! What was I thinking?
Again, thanks so much!

Here's the real lowdown on the light up.

Your question is multifaceted. Recording and ON-AIR lights have been used since the very beginning. The very beginning. Before Christ. Not really but...

At radio stations, the announcers control room or studio speakers, were connected to a relay operated muting circuit. When the microphone is turned on, the monitors were cut off. So as to avoid any kind of chance of acoustic feedback.

Obviously, recording studios don't use relay operated microphones. So at recording studios, there was a separate switch on the wall.

In real recording studios and broadcast operations, electrical wiring is especially constructed, divided, balanced. So lights were put on lighting circuits. Equipment was put on equipment circuits. An attempt was made to evenly balanced the loads, as best as possible. Otherwise there was no other interconnection or interaction between equipment and lights. Some even used fire engine style emergency rotating lights. Which were also somewhat common at Hollywood back lot sets when filming. Bringing to bear a much more harsh response should you make any noise at all LOL.

Flashing strobe lights with red filters are also good. A full wet bar is also recommended. And don't forget to get some Remy.

You got me.
Mx. Remy Ann David

Hey Remy
Great down an' dirty history lesson! Back when I had a bit of cash I was able to pick up a used Equitech toroid transformer from an unfortunate closed studio in Nashville. Quiet, balanced AC and I swear the bass frequencies are tighter and the highs sweeter (or is that my psychoacoustic rationalizing/justifying brain, or what's left of it, trying to validate the purchase?!).

I love the idea of "fire engine style emergency rotating lights...Flashing strobe lights with red filters"! I can think of a few musicians who could use the not so subtle queues, including old guys like me. The wet bar is a bit off my radar but the Remy is always welcome!

pcrecord, post: 417877, member: 46460 wrote: Yeah recording without the knowledge of artists is one of my guilty pleasures !!

Yup. Me too. I can't count the number of times when I would tell the client, "okay, we're just gonna roll the track and let you warm up a little. Don't worry, we're not recording yet, I'm just gonna get some levels here.."

Except what they didn't know was that during recording sessions, I was always recording. You never knew when that incidental warm-up take might just turn out to be the best of the session... plus, plenty of musicians - not just rookies, either but plenty of veterans, too - get a little wiggy when they know that the "red light" is on.

Funny thing...I can step out onto a stage in front of 8000 people and play with no problem - very relaxed, having fun... but when I step up to a studio mic, in front of two or three people, I can still get a little anxious myself, even after 34+ years in this business....

So true folks. Even if I just have my wife or a few friends listen to something I'm doing I get all up in my head, just like when I know the tape is rolling. I then have to drag myself back outa there and into the groove. Put me in front of a crowd and I'm fine, especially if don't know them. I don't even want to know the psychology involved but I'm pretty sure it's related closely to my ego....what...a musician with ego....no never!!!

I realize this is not the direction this thread is going, but if anyone is interested in having signs that really do indicate that a DAW is recording please check out the Blue Cat Plug n' Script plug-in.

http://www.bluecataudio.com/Products/Product_PlugNScript/

I just purchased it this week and so far I am very impressed. Although it is intended to be a tool for the user to write scripts, it does come with some example scripts. One of those, the Transport Monitor allows you to get a MIDI output from your DAW when it is actually recording. You don't need to buy it to see if it is what you want, Blue Cat has a demo available.

Of course, that is only half the project. You still will need to decode the MIDI. There are many products that will do that. I am using a Highly Liquid (that's the company name) MSA-T.

http://store.highlyliquid.com/collections/midi-decoders

It can control a relay or whatever you want to use to switch the power to the sign.
I haven't done that for several years, but the last time I did do it I used a solid state relay. Something like this....

http://www.digikey.com/product-detail/en/D2410-10/CC1079-ND/221772

The advantage of these things is that they are completely quiet.

Good luck!

REMY: "recording studios don't use relay operated microphones" What!!! Sacrilege!! Please, say it isn't so. Everything needs relays---lots of them---more, more, more---. I hope that I am not the only person here that has a 24 volt, positive ground plant battery!