Reducing RFI at Home From Lighting Fixtures? 126
amper asks: "I'm in the process of building a new home recording studio. When I originally moved into my new (very old) house, I decided that in the interests of conserving energy, I would replace most of the incandescent lighting fixtures or lamps in my home with fluorescent fixtures or compact fluorescent replacement lamps in those fixtures which could not easily be replaced. Unfortunately, these fixtures are creating a massive amount of radio frequency interference in my home. The worst culprits seem to be the dimmable fluorescent fixtures in my living room. Barring replacing all my fixtures and lamps with conventional incandescents, can anyone point me in the direction of alternatives? Is it possible that the decreasing quality of most home goods has led to a decreasing quality in fluorescent ballast systems that are much more noisy from an RFI standpoint? Some of these fluo's are so noisy, they even emit audible sound! It's gotten so bad that I can't even play an electric guitar without turning off all the non-incandescent lighting in my house, which pretty much limits me to playing and recording during daylight hours (when I'm supposed to be out making money)."
No easy answer (Score:1)
Re:No easy answer (Score:2)
Lights off... (Score:1)
Focus on ground loops, not on RFI sources. (Score:5, Informative)
The main thing that makes electronic circuits sensitive to noise is ground loops. Often, signals travel through cables that have two wires or a central wire with a shield surrounding it. Normally, equipment (whether it is an oscilloscope or consumer-grade audio equipment) has a common ground, which means that the neutral wire of each and every input and output is connected. If you have more than two pieces of equipment interconnected, it is likely that there are loops in the ground wire, for example the cable from mixer to some effect generator, and the wire back. All these loops acts as antennas that can pick up noise. Having shielded cables doesn't help because it is the shield, that acts as ground wire, that causes the problems.
The first and simple step is to have all wires bundled as close together as possible, such that the area inside the loops is as small as possible. The next step is to upgrade your equipment to stuff that has balanced inputs, with those big XLR connectors. Here the shields are really shields against RF interference, while the signal is carried by two wires inside the shielded cable. Balanced signals means roughly that the equipment measures the signals on the two signal wires completely independent from the ground.
Re:Focus on ground loops, not on RFI sources. (Score:2)
Re:Focus on ground loops, not on RFI sources. (Score:4, Informative)
CMRR (Common Mode Rejection Ratio) is a measure of how well an input circuit cancels out this kind of noise. When looking at the specs for gear this is one of the important but often overlooked numbers to check out.
Re:Focus on ground loops, not on RFI sources. (Score:2)
Re:Focus on ground loops, not on RFI sources. (Score:2)
Re:Focus on ground loops, not on RFI sources. (Score:2)
Armored cable (AC, MC, or MC-lite) or conduit are, effectively, shielded wiring systems.
Re:Focus on ground loops, not on RFI sources. (Score:2)
In general, the biggest problem with dimmable ballasts is when they are not properly grounded. Check the grounds, make sure they are installed with the phase conductors, and make sure that they run with the phase and neutral wiring.
Also along these lines, if you have three-way switching check and make sure the switch leg properly in
Re:Focus on ground loops, not on RFI sources. (Score:2)
For fx processing and stuff, yeah, but you're probably still going to have an unbalanced signal from your source.
Re:Focus on ground loops, not on RFI sources. (Score:2)
There's no need for that because the cable from amplifier to guitar is a "dead end", that cannot participate in a ground loop. I'm not that much into indie rock, but I assume that a guitar is nothing more than a microphone from an electrical point of view. Just a device with two wires coming out of it. Guide those two wires through a shielded cables and voilà, you have a balanced signal.
Re:Focus on ground loops, not on RFI sources. (Score:1)
Re:Focus on ground loops, not on RFI sources. (Score:3, Informative)
If the OP would care to email me at coastalnet.com I'll explain to him how his guitar can be fairly easily modified to greatly reduce the interference which it picks up, which may or may not be due to his lighting.
Light dimmers, incandescent or flourescent, are no
Re:Focus on ground loops, not on RFI sources. (Score:2)
That is actually exactly what I am claiming in the special case of a microphone. The microphone (or pick-up element) is not electrically connected to ground, which only serves as a shield. Hence, the two signal wires are completely floating with respect to ground, which is almost equivalent to a balanced output. That is how a dynami
Re:Focus on ground loops, not on RFI sources. (Score:2)
Single coil pickups are the worst about this kind of problem. Something about how the signal is generated by the inductive coil. However, humbucking pickups do help in this manner, but I'm not up on the electrical theory to s
Re:Focus on ground loops, not on RFI sources. (Score:1)
Re:Focus on ground loops, not on RFI sources. (Score:2)
Almost certainly caused by electrical noise from your alternator rather than a ground loop.
Re:Focus on ground loops, not on RFI sources. (Score:2)
Re:Focus on ground loops, not on RFI sources. (Score:2)
Typically speaking a high whine is the result of diode or regulator failure. There's anywhere from six to twelve diodes in a modern alternator and if any one of them goes out you typically will have serious noise. You can put your vehicle's electrical system under load (Defrost, headlights, blower, et cetera) and measure the AC voltage at your battery terminals, which is going to be similar to that found directly at the alternator. If it's over 0.5VAC, then at least one diode (group) is bad and not only ar
Re:Focus on ground loops, not on RFI sources. (Score:2)
Re:Focus on ground loops, not on RFI sources. (Score:2)
fluorescent lights in the livingroom? (Score:1, Troll)
I'm shocked.
Re:fluorescent lights in the livingroom? (Score:2)
Here is an example of some:
http://www.lightbulbsdirect.com/page/001/C
There are also ones like this, closer to form (via plastic cover)
http://www.lightbulbsdirect.com/page/001/
Re:fluorescent lights in the livingroom? (Score:2)
Re:fluorescent lights in the livingroom? (Score:2)
Was that a lame attempt at a pun? Because I can't comprehend why you're surprised that people have flouros in their living rooms. Compact flourescent light globes are incredibly common. They have lower power consumption, they last longer, and the new ones have a similar light to incandescents. My entire house is fitted with compact flouros.
Re:fluorescent lights in the livingroom? (Score:1)
Don't really know if it is true, but it would be interesting to know, since we've could be giving ourselves the potencial to develop skin cancer while sitting on the light of these bulbs.
Re:fluorescent lights in the livingroom? (Score:3, Funny)
Re:fluorescent lights in the livingroom? (Score:2)
I think that the glass is supposed to block UV, but I could be wrong. Or maybe the glass is not 100% effective.
Re:fluorescent lights in the livingroom? (Score:2)
(ie pinball machines in my case)
Re:fluorescent lights in the livingroom? (Score:2)
The other rooms however, need more decorative lighting, and thus unsuited to the industrialised look of the flouros.
But I leave all my lights off most of the time anyway.
Good point about RF interference as I am looking for a best solution for a wireless remote for my PC, for myth and for xmame, going through one wall. I am buying an RF set to connect my TV out PC card to my TV, and xmame on a 12" B&W portable here I come!
OK, so it will be a 42 plasma maybe. or 3
Re:fluorescent lights in the livingroom? (Score:1)
If you don't have the space, is a cost/quality thing - big plasma looks great from further away, but grainy (even on $7000 sets in my exp) close in. LCD can be better quality and also consumes less power and produces less heat than Plasma.
Enjoy - I'll continue saving up for the upgrade from my 14" crt...
Re:fluorescent lights in the livingroom? (Score:2)
Huh, are you stalking me?
I just reread that comment. You managed to not understand the point despite it being spelled out for you. I remember dismissing it as the ravings of a crazy person. Now that I know you're fixated on the event, I'm convinced there's something wrong with you.
Flourescent lighing (Score:2, Interesting)
You could replace your fittings with LED based fittings - the power consumption is lower, the light can be better & brighter, and the bulbs (LEDs) last longer. Also, they run off DC, so no noise!
Re:Flourescent lighing (Score:1)
Re:Flourescent lighing (Score:2)
No, that's mercury vapour lamps (don't get in my way, I just got off a 3-hour interferometry lab dealing with the bastards). Fluoresecnt tubes tend to be filled with noble gases, e.g. Neon.
Re:Flourescent lighing (Score:2)
Fluorescent lights are filled with a mercury vapor. So are "Mercury Vapor" lights. Though the two operate differently.
See http://science.howstuffworks.com/question293.htm [howstuffworks.com]
Re:Flourescent lighing (Score:1)
Interferometry lab. Mmmmmm. Prisms... So glad I finished my phys degree last year.
White light *frequency*? (Score:2)
Re:Flourescent lighing (Score:3, Informative)
If you need more information about properly disposing of lighting waste click on the link at
Re:Flourescent lighing (Score:2)
Re:Flourescent lighing (Score:1)
Re:Flourescent lighing (Score:1)
Well I get them for less than a buck a piece ($5 for a six pack) at Costco. Not sure how they do that, since they can be up to $10 in other stores. And yes these are nice small modern CF bulbs.
Re:Flourescent lighing (Score:1)
RFI Solutions (Score:5, Informative)
1) You can get ferrite rings of various diameters. Try winding a couple of turns of the cord leading to the light through one of these rings. The ring should be as close as possible to the fixture.
2) Wire RF chokes in series with the fittings. These work in a similar way to the ferrite rings but are more effective.
3) It's possible to obtain capacitors that are rated for 110/220 volt operation. Have a look inside a PC power supply and you may see one, they are normally encased in yellow transparent epoxy. Wire one of these across the fitting.
And finally.........
4) Ask for help from the right people. Try and find either a local radio ham or (even better) a local ham club. These guys will be experts at fighting RFI and will help you out.
Ed Almos
Budapest, Hungary
Re:RFI Solutions (Score:3, Funny)
Dude, please tell me you are accessing slashdot through a RF connection, using some antenna made out of bean tins and dust-bin lids.
Awesome...
[/geek awe]
Re:RFI Solutions (Score:3)
Re:In the interests of science... (Score:2)
Know what you're doing! (Score:2)
An educated layman can do this, but if you aren't up to passing the electronics portion of a ham test you should probably defer to people who know more than you do. This may mean as little as finding good designs on the web... b
Re:Know what you're doing! (Score:2)
A 5000mfd capacitor rated for 110/220 volt operation would probably be about the same size as the light fitting. Disc ceramic capacitors MIGHT work if you are very careful about the voltage rating but the devices I was referring to are known as X2 rated capacitors (I've now had a chance to look this up). The X2 rated capacitor I am looking at now is rated to 275
Once again.... (Score:2)
Cables? (Score:2, Insightful)
Is all of your equipment properly shielded and grounded?
These would be the first things I'd check.
Re:Cables? (Score:2)
Re:Cables? (Score:2)
Re:Cables? (Score:2)
You are recommending the replacement of all his gear to go to a balanced sound board instead of a guitar and amp combo.
Using 100% shielded cables is a big improvement in noisy environments, but they rarely have the flexibility and durability of a typical guitar cord. A typical guitar cord uses a braided shield, not a 100% foil shield with a drain wire.
How about... (Score:2)
Since you're "building" your own studio, I'm guessing your're going through and soundproofing the walls and the like.
Why not try making the walls a faraday cage. Line the interior of the walls with a good layer of aluminum foil or fine brass screening.
Re:How about... (Score:2)
It's much cheaper and just as effective to install rigid conduit to all the fixtures. Let the wire be noisy inside the conduit. Put a few Cornell Doubler noise filters between the dimmers and the breaker panel. This isolates the noisy branch from everyting else.
Look for people who do Tempest power conditioning. They do a good job killin the noise radiation.
Re:How about... (Score:2)
You've got to admit, though.... Tinfoiling the walls would be much more fun!
Install dual lighting systems. (Score:1)
Re:MOD PARENT UP !!! (Score:1)
Why would anything like that ever get modded up?
You must be new here.
Simple Solution (Score:1)
Many before in the discussion have said that reducing eliminating ground loops in your equipment will eliminate RFI from being picked up in your equipment, however I doubt you are a Electrical Engineer. My suggestion is to replace all the flourecscent bulbs in your studio with these Led Floodlights [slashdot.org], these would be easy to install, more efficient than flourescent, and will be the way everything is lighted years from now ( geekstat +1 ).
One word for you (Score:2)
Ditch the dimmers. (Score:4, Informative)
(The article mentions a number of problems, including the fact that you might be significantly reducing the lifetime of your tubes by dimming them. YMMV.)
What I have in my living room are some long-live fluorescents to provide the bulk of the light, and some incandescents to change the colour and make the illumination more interesting. You might be able to do something similar without having to hook the tubes themselves up to the dimmer.
How about Faraday Cages? (Score:3, Informative)
Re:How about Faraday Cages? (Score:2)
Well, in principle, the mesh size should be much smaller than the wavelength of the radiation you want to shield. For example, a microwave oven: 2.5 GHz, 10 cm wavelength, 3 mm mesh size. Now if you want to block audio frequencies, 20 kHz frequency, 15 km wavelength, so a 450 meter mesh size should be enough...
The problem is that you are much closer to the source than the wavelength, i.e. in the near field. You have to blo
Re:How about Faraday Cages? (Score:2)
Re:How about Faraday Cages? (Score:2)
I'm quite sure that a small magnet will pick up paper clips right through chicken wire. :-) A reasonably thick layer of iron without holes will probably shield low-frequency magnetic fields. Howev
Re:How about Faraday Cages? (Score:2)
Maybe all the guy needs is a Faraday Cage surrounding himself and his recording system....
Re:How about Faraday Cages? (Score:3, Informative)
Now for the bad news:
a surprisingly vast amount of professional audio gear uses 1/4" unbalanced connectors. Of the synths, samplers, a
Fluorescent lighting in a recording studio? Gah! (Score:1)
> moved into my new (very old) house, I decided that in the interests of
> conserving energy, I would replace most of the incandescent lighting fixtures
> or lamps in my home with fluorescent fixtures or compact fluorescent
> replacement lamps in those fixtures which could not easily be replaced.
There are two places where fluorescent lighting really doesn't belong: a
recording studio is one of them. (The other is a
have you asked yourself the basic question... (Score:2, Insightful)
I mean they emit horrid RF noise, if you have sensitive hearing which I imagine you do as a recording engineer they sound terribly annoying, and they make everything look wrong (though I suppose some folks are more bothered by that than others).
Personally if I lived in a house with all flourescent lighting, I would just want to go outside all the time, and I would be kind of grossed out by how people, artwork, and even food looked...but that's me.
Re:have you asked yourself the basic question... (Score:2)
The new ones that replace regular bulbs have a much more balanced spectra. They look much more like natural light. They also don't cause CRT flicker (although I have found some that do).
--
Evan
Wow... some savings (Score:2)
The EPA and state environmental agencies are interested in reducing peak load on the power grid to avoid building power plants without brownouts.
This often doesn't translate into net savings for the consumer. While a 13W fluorescent bulb emits light similar to the 40W incandescent bulb, it also costs 4-10x more, depending on bulb quality.
To top everything off, you're now living with all of the disadvantages of fluorescent light. Rip out of the fluorescent crap and
I guess you've never toted them up. (Score:4, Informative)
Lifespan of a 150-watt incandescent is what, 200 hours or less? Figuring 10 bulbs at $1 each plus 300 KWH of electricity @ 8 cents, the same 2000 hours of light would cost $34. Looks like your approach is penny-wise, pound-foolish.
Re:I guess you've never toted them up. (Score:2)
Maybe in my shop light, because it gets slammed around a bit.
I usually have to replace my porch light every 6 months because I forget and leave it on most times... so let's see:
4 months = 2880 hours. I'd say I get probably 2500 hours out of the porch light.....
Typically CFs last longer, or so I thought that was their claim to fame....
Re:I guess you've never toted them up. (Score:3, Informative)
Do the math! (Score:2)
60W incand: Bulb $0.50 / 1000h + elec $7.20/kh = $7.70/kh
13W c.flor: Bulb $4.00 / 8000h + elec $1.56/kh = $2.06/kh
CFs are great, need little replacement (especially good for ceiling fans). But dimmers are noisy even on incandescents, and horrible on CF.
Re:Wow... some savings (Score:2)
The actual breakdown of the bulb's TCO will vary from bulb manufacturer to manufacturer, bulb type, as well as usage. Flicking a light on and off can decrease the usable lifetime compared to a bulb that is just left on or only turned on/off limited number of times.
Typical usage for
and labor... (Score:2)
That's easy! (Score:3, Funny)
Simple Tips (Score:2)
2) Make sure your equipment itself doesn't have ground loops. Check out this video on TaylorGuitars.com [taylorguitars.com] about the importance of a good ground.
Re:Simple Tips (Score:2)
No master electrician worth his salt would go and do that, but whould be more than glad to help you out with your problem... Odds are that the older wiring has issues with grounding and is in need of proper grounding... Call a electrician and let him deal with it.
Simple solution? (Score:2)
I'd guess that the interference is coming in through the power lines. Others have talked of filtering, ways of rearranging your lifestyle, etc. But nobody has mentioned the obvious: plug your audio equipment in through a UPS. Most UPSes have line conditioners built in. I'd expect that they would eliminate most line noise. Just a guess though. Still, it's worth trying since it's so simple.
Interference through the power lines??? (Score:2)
Any audio equipment worth its money ought to have a power supply that adequately prevents line noise from penetrating into the low-voltage circuits. I believe the main issue is that the primary and secondary coils in the transformer should not be too close together, as that would create a capacitative coupling between line voltage and secondary.
Of course, a computer power supply is not rated for use in audio equipment. If you live in a
you said its an old house... (Score:1)
this might not be useful (Score:1)
A fix would be to get a "shielded" tranformer.
Buy an online UPS (Score:3, Informative)
I don't remember how much these things cost but an online UPS (one that converts AC -> DC feeds the battery and then feeds the PC/equipment from the battery) can reduce line noise significantly. It isn't the most elegant solution but feeding pc/sound card/sound equipment from a noiseless source can improve things considerably and it is very easy to install. APC has a specific solution for high-end audio/video systems that appears perfect for you (its called a power conditioner and is, essentially, an online UPS with very little battery time). Caution: the words "high performance AV system" usually mean $$$$$$. Check the link http://www.apcc.com/products/family/index.cfm?id=3 10&ISOCountryCode=US [apcc.com]
Alternatively you may try balanced XLR->XLR cables that are used by professionals. I use these for my microphones (which provide a very low signal) and I am quite happy. Note that 4.5mm jack can also be balanced but you have to explicitly request it. Also bear in mind that a strong signal is much less sensitive. Long lengths of microvoltage-level signal are a not a good idea but line-level (-5/+5) signal is quite resistant. You may also buy ferrite cores for your cables (even power cables that have ferrite cores pre-installed!) and see if it makes a difference. Shielded cable may also be useful. Don't go spending a lot before trying.
Finally, always remember: a very good power supply (as in expensive audio equipment) can handle noise quite effectively.
P.
Re:Buy an online UPS (Score:1)
Re:Buy an online UPS (Score:2)
Usually audio-video equipment is very demanding in terms of power consumption. An amplifier in the 2x100W RMS range can easily draw 400W of electrical power continuously, which would roughly require a ~800VA supply. (Yes, I know that in theory 1V*1A = 1W, but unfortunately UPSes do not always work that way ;-)).
I'm a little suspicious about the *sonic* performance of line conditioners, unless they have been specif
Re:Buy an online UPS (Score:2)
Energy saving bulbs don't save energy (Score:2)
Re:Energy saving bulbs don't save energy (Score:2)
If he's using electric heat, then there's no point in using flourescents to save energy, since all the light that is produced eventually turns into heat anyway as it strikes objects in the room. As you said, a flourescent provides less thermal energy to the room, re
Re:Energy saving bulbs don't save energy (Score:2)
To go a step further-- get some incandescent lights that run off 12V DC. There are fixtures that use wires or tapes that you screw small lamps into (with MR16 spot or flood bulbs). They have a transformer unit and a bunch of wire that you run where you wan to put the lights, and you can put bright light right where you want it. The 12VDC won't cause any in
Halogen (Score:1)
Fix the leaks before tweaking the system (Score:2)
Sealing drafts and insulating walls, floor, and ceiling to the greatest practical degree will provide a greater energy cost savings per unit of currency spent than high-efficiency lighting fixtures or any other "energy efficiency" exercise. It should always be your first course of action.
Put another way, you can spend $500 to squeak out one extra mile-per-gallon in your car, but i
The downside (Score:2)
That's not necessarily a bad thing, unless you've already invested in this technology.
Simplify things. (Score:2)
We only used incandescant lighting. There were several switchable lighting circuits in each room with only a couple of smallish fixtures on each one; "mood" was controlled simply by turning lights on and off. Some of the lights were purposefully colored, but most where whatever we could find c
Balanced power (Score:2)
Things I probably should have mentioned... (Score:2)
1. I am not an EE, but I did go to Carnegie-Mellon for Theatre Production as a Lighting and Sound Design student. I am a fairly knowledgeable person, however, so I do understand most of the basic electronics concepts that have been addressed, especially the audio concepts. Plus, I've done quite a bit of studying on electronics since college (if I had it to do over, I'd probably go EE!).
2. Yes, the
Had this problem in college (Score:2)
In a college recording studio I used, we simply switched off the fluorescents and used a couple (non-dimmed) incandescents while we were recording.
The noise from the fluorescents may not be RFI in the over-the-air sense. It may be introducting spikes into your power lines. Use high-quality surge supression and, if possible, power your audio gear with a dedicated circuit that's isolated from the one running the lights.
Standard fluorescents (I don't know about the CFs) create noise primarily at the A/C