ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  
Pages: 1 [2] 3   Go Down

Author Topic: Light dimmer box EMI?  (Read 6664 times)

Erick Swihart

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
Re: Light dimmer box EMI?
« Reply #10 on: April 26, 2010, 04:43:34 pm »

You mentioned earlier that the noise will come through channels with nothing in them.  Have you tried unplugging the snake entirely and recording something through the board checking for the noise.  It may be as simple as moving the snake when you have time.

Those fixtures are likely going to require something a little beefier than the 300 dollar portable dimmer packs that have been suggested here.  Check around for used dimming.  You can get old analog packs really cheap and if you have a qualified electrician in the theatre getting them setup with dmx converters might be a cheap option.  A theater I worked at with similar money issues picked up 24x2.4k channels of old NSI dimmers with the Dove DMX converter and a bunch of spare triacs for $350.  Though the dimmers are old and some of triacs needed to be replaced, they work great for the venue until they get the grants needed to get everything fixed up properly.

Does the noise go away when the dimmers are turned all the way up effectively running the lights at full power?  If that is the case, maybe you can come up with a way to switch/diffuse the light on a couple of fixtures and only run them when you need less light.

Also, not sure where you are located but there are a few chains of large supermarkets that are actively replacing fixtures used to light produce with newer energy efficient lighting.  Our theatre managed to get 36 Altman elipsoidals and a bunch of lamps donated.  Worth looking into.

Just a couple thoughts.
Logged

Leo House

  • Newbie
  • *
  • Offline Offline
  • Posts: 15
Re: Light dimmer box EMI?
« Reply #11 on: April 26, 2010, 07:08:14 pm »

Quote:

You mentioned earlier that the noise will come through channels with nothing in them. Have you tried unplugging the snake entirely and recording something through the board checking for the noise. It may be as simple as moving the snake when you have time.


No, I haven't tired that, prolly should tho.(Its somewhat difficult to go down anytime to record, not that I don't have access to the theater, but the fact that I have to use my sisters laptop since I don't have one of my own HAHA) I'll have to get her to let me use it sometime during the week to try that.

Moving it would be difficult, cuz the snake is run through the walls.  Lord knows how old it is, and probably DOES need to be replaced, but it'd take more then me to be able to get it all out and rewired to the stage HAHA.


Quote:

Those fixtures are likely going to require something a little beefier than the 300 dollar portable dimmer packs that have been suggested here. Check around for used dimming. You can get old analog packs really cheap and if you have a qualified electrician in the theatre getting them setup with dmx converters might be a cheap option. A theater I worked at with similar money issues picked up 24x2.4k channels of old NSI dimmers with the Dove DMX converter and a bunch of spare triacs for $350. Though the dimmers are old and some of triacs needed to be replaced, they work great for the venue until they get the grants needed to get everything fixed up properly.



Yeah.   Ideally, I wouldn't mind getting new light fixtures aswell, something that takes less power, but same amount of light, aswell as give us color options and stuff! We have a new light setup at church in the fellowship hall, and its all LEDs, we can change colors, and probably do all kinds of other stuff that isn't setup at the moment.  I'd love something like that, but it'd probably have to be somewhat bigger lights to beam down to the stage that far.


Quote:

Does the noise go away when the dimmers are turned all the way up effectively running the lights at full power? If that is the case, maybe you can come up with a way to switch/diffuse the light on a couple of fixtures and only run them when you need less light.


For the most part yes. To get the noise really bad, the gain has to be cranked up pretty far, and the noise it increased when the lights are mid range, but lessen when they are full, or almost off.  For the most part, it would not be too much of an issue, but a couple of the kids, need those mics REALLY hot to be able to hear them.(No matter how much coaching they get to sing out.)



On a different note, since there is only one more major show this season, is there any way I might be able to shield my camera?  Like aluminum foil over the tape compartment or something easy like that? Just something to help keep any EMI away from the tape?
Logged

Duane Massey

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2189
    • http://www.ozknozz.com
Re: Light dimmer box EMI?
« Reply #12 on: April 27, 2010, 12:25:29 am »

Replace the dimmers with switches. Then plan out a new system from scratch with the proper gear.
Logged
Duane Massey
Houston, Texas, USA

Leo House

  • Newbie
  • *
  • Offline Offline
  • Posts: 15
Re: Light dimmer box EMI?
« Reply #13 on: April 27, 2010, 01:11:41 am »

haha, umm, k. Probably the thing to do, but not exactly helpful. Kinda already been stated, in better detail, and as I mentioned, I'm a sound guy, a fairly new one at that. I honestly don't know the fist thing about lighting systems.  I really have no knowledge base to even begin planning something like this, let alone know how to replace anything with anything, or know how to wire anything like that.

Kinda might as well have just told me to replace the coal burning generator with a nuclear reactor, cuz I know bout as much at doing that as what you just told me LOL.
Logged

Jon Evans

  • Newbie
  • *
  • Offline Offline
  • Posts: 13
Re: Light dimmer box EMI?
« Reply #14 on: April 27, 2010, 01:15:55 am »

You will not realistically be able to shield your camera.

If you cannot find an electrician to figure out exactly how your system works and therefore what the best part to replace would be, you need to figure out how to move your sound and video to a better location.

I would start by setting up the camera in a different part of the house, and on a different circuit than the lighting.

If possible, figure out how to move your mixer and gear for the show.  If the lighting dimmer switches can't be moved, you can buy/rent/borrow/find some XLR extension cables and move your whole rig away from the snake position (assuming you have no snake leeway since the snake is built into the wall).

Basically, what everyone is trying to tell you is that if you can't replace the sketchy light setup, there is NO WAY to get rid of that hum that doesn't involve moving the sound gear away from the lighting gear (physically and electrically).
Logged

Leo House

  • Newbie
  • *
  • Offline Offline
  • Posts: 15
Re: Light dimmer box EMI?
« Reply #15 on: April 27, 2010, 02:56:31 am »

Yeah.  We'd actually have to have 1/4th male to female extenders aswell, since the speaker cables are also ran through the wall.
I do know that the lighting, and the audio(and my camera) are on two completely separate breakers already. I can't be sure, but I think the lights have their own breaker. I was hoping maybe some foil, or shield plats could be used to help block EMI from the tape alittle bit. I moved it over there, so I could control it and zoom in/out during performances. Its my personal cam, and I am an amateur filmmaker on the side, so I'm nervous about letting just anyone use it LOL.

I doubt its feasible to do anything for this show them, but I'm defiantly going to work on some things in the off season to try to get it better.  I'll talk to that guy, he knows some people that might be able to get us some newer used equipment pretty cheap. We also are trying to start a 4H group, so fixing things up upstairs might be a good project. Right next to the table on the floor, is a drop off, where the heating/air blowers are, that's why we can't just set up tables anywhere.

I guess its not a huge deal right now, its been setup like this for a very long time, but I was just hoping there was some type of cheap fix that could help in the mean time.
Logged

Duane Massey

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2189
    • http://www.ozknozz.com
Re: Light dimmer box EMI?
« Reply #16 on: April 27, 2010, 11:21:50 am »

Leo, I wasn't being sarcastic, replacing the dimmers with switches would be inexpensive and would solve your noise problem. Obviously you wouldn't be able to dim the lights, but I've worked in several community theaters in my younger days that had no dimmers.

There is no low$$ easy solution that will not require at least some electrical skills. At the very least the audio and lighting gear need to be physically separated as far as possible. Even that would not probably solve the problem completely, but it might make the problem more workable.
Logged
Duane Massey
Houston, Texas, USA

Leo House

  • Newbie
  • *
  • Offline Offline
  • Posts: 15
Re: Light dimmer box EMI?
« Reply #17 on: April 27, 2010, 03:41:08 pm »

I know, I didn't mean to reply harshly. Its just my utter lack of knowledge in this area, I really wouldn't know where to even begin on doing that much I'm afraid.

Its probably going to have to come down, to simply finding someone other then myself, that knows what they are doing here, and will be able to install/wire, or do whatever to hook up a new system.

On a different note, would anyone here know, if I have something that has bed, black and ground wires, and something that has blue, white and ground wires, and I had to connect them. What color would go to what? Obviously ground to ground, but I'm not familiar with the blue and white wire color scheme.  Its for one of the stage XLR inputs. The new XLR jack for the stage has blue and white, but the "snake" I guess, is red and black wiring.
Logged

Tony "T" Tissot

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3902
    • http://www.4dbsound.com
Re: Light dimmer box EMI?
« Reply #18 on: April 27, 2010, 04:38:14 pm »

Leo House wrote on Tue, 27 April 2010 12:41

I know, I didn't mean to reply harshly. Its just my utter lack of knowledge in this area, I really wouldn't know where to even begin on doing that much I'm afraid.

Its probably going to have to come down, to simply finding someone other then myself, that knows what they are doing here, and will be able to install/wire, or do whatever to hook up a new system.

On a different note, would anyone here know, if I have something that has bed, black and ground wires, and something that has blue, white and ground wires, and I had to connect them. What color would go to what? Obviously ground to ground, but I'm not familiar with the blue and white wire color scheme.  Its for one of the stage XLR inputs. The new XLR jack for the stage has blue and white, but the "snake" I guess, is red and black wiring.

Color is "untrustworthy" if you don't know the provenience of the cables. You need to know how someone before you wired them.

I NEVER trust any installed cable, unless it's a venue I know - or the gear is of a certain professional, "branded" standard. I always check with a cable tester for an installed snake (just string an XLR cable to the booth and have someone plug subsequent channels as you go. Takes only 5 to 10 minutes.) If you have a raw, un-terminated end to deal with, do a visual inspection of the far-end to see which pins are which. Then test.

It's a simple as pin 1 to 1, pin 2 to 2, 3 to 3.
Logged
MNGS
ProSoundWeb - Home of 50,000 audio professionals - and two or three curmudgeonly SOBs.

Leo House

  • Newbie
  • *
  • Offline Offline
  • Posts: 15
Re: Light dimmer box EMI?
« Reply #19 on: April 27, 2010, 05:03:05 pm »

Well, here is a VERY crude drawing of what the stage is like, and how its setup underneath. (You actually have to craw through a small door on the front, and get under there to wire anything.)
Maybe it'll help you guys, tell me what I need to do HAHA

http://img227.imageshack.us/img227/5404/stage.pnghttp://img227.imageshack.us/img227/5404/stage.png

The under the stage pic, the little brown dots, represent holes in the wood, about an inch thick that go to the actual XLR jack, so I can't see where each cable is connected at. The wires are alittle neater then what I was able to show with my poor artist skills.

The 6th jack, the wires are completely removed from the old jack, so I also can not see where each one was on that either. (Mostly my fault, I tried to remove the broken one, not knowing there wasn't enough wire to come out without pulling them off.)

The new jack, has about 8" of cable already attached, but as I mentioned, the colors are different. The ends need to be striped on both, and twisted together I guess, but I don't know how to tell which is positive and which is negative. (Ground on both is silver, so that's easy.



Logged
Pages: 1 [2] 3   Go Up
 

Page created in 0.047 seconds with 18 queries.