Reducing RFI at Home From Lighting Fixtures?

No easy answer by arthurhh · 2004-12-02 22:51 · Score: 1

By the very nature of there operation Fluos will be electrically noisy. Audiable noise is due to loose fitting of the ballast and surrounding items. First post ?

--
24 Hours in a day - 24 Cans of Beer in a carton - Coincidence

Re:No easy answer by Mattcelt · 2004-12-04 05:47 · Score: 1

I would suggest looking into LED lighting. There are almost no emissions outside the visible spectrum, afaik.
Re:No easy answer by FSK · 2004-12-07 06:24 · Score: 1

Find someone who works in film lighting, they deal with stuff like this all the time.
It's been 10 years since I changed career's so unfortunately no product names are
coming to mind but I remember when I was a film electrician we had special ballast for
fluorescents that solved 90% of the type of problems you're talking about. You can also look into
"hospital grade" florescent ballasts that are tested to make sure they don't interface with
monitoring equipment.

From personal experience I can tell you that Japanese ballasts produce a lot less interference
(they have to made in Japan not just made by a Japanese company). The Japanese moved to
fluorescents a lot earlier then anyone else and the ballast made for the Japanese market
are supposed cause less interference.

--
When punk rock is outlawed, only outlaws will have punk rock.

Lights off... by pyrote · 2004-12-02 22:57 · Score: 1

well you could allways start playin blues.

--
THE WORLD IS GOING TO END!!!! eventually.

Focus on ground loops, not on RFI sources. by hankwang · 2004-12-02 23:03 · Score: 5, Informative

I come from a physical laboratory where we have to measure small signals with an acceptably low noise despite the presence of laser flash lamps, or even high-voltage discharges in more or less open air. The best way to avoid RF interference is not to remove all RF sources, but to design the electronic circuits correctly.

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.

--
Avantslash: low-bandwidth mobile slashdot.

Re:Focus on ground loops, not on RFI sources. by ottawanker · 2004-12-02 23:27 · Score: 1

Its also important to point out that with balanced connections one of the wires carries a signal that is a "mirror image" (180 degree out of phase) of the original signal. The wire carrying the actual signal is normally termed "+", or "non-inverted", and the wire carrying the phase inverted signal is normally termed "-", or "inverted". "Phase inverted" means inversion of "plus" and "minus" voltages and currents - an exact mirror image.
Re:Focus on ground loops, not on RFI sources. by rhild · 2004-12-03 00:51 · Score: 4, Informative

To expand on that, any RF noise that gets into the cable will appear in phase on both signal conductors, which will result in it being cancelled out in the input circuit of the device the cable is feeding, if the device has balanced inputs.

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. by eap · 2004-12-03 02:16 · Score: 1

If it's a very old house, as he states, it likely has knob and tube wiring instead of shielded 3 wire NM cable. K&T generally does not use a common 3rd wire ground.
Re:Focus on ground loops, not on RFI sources. by AsbestosRush · 2004-12-03 02:59 · Score: 1

There are very few guitars with balanced outputs that I know of. Not that it hasn't been done, but you start getting into the "seriously boutique" area when you start asking for this.

For fx processing and stuff, yeah, but you're probably still going to have an unbalanced signal from your source.

--
EveryDNS. Use it. It works.
AC's need not reply
Re:Focus on ground loops, not on RFI sources. by Webmoth · 2004-12-03 03:43 · Score: 1

Um, the NM stands for "Non-Metallic." It's not shielded. Go to Home Depot and take a close look at the NM cable there, it's non-twisted pair, non-shielded. Ripe for RFI/EMF. The same goes for knob-and-tube, but those conductors are spaced further apart, compounding the problem. Not to mention that the insulation is probably old, brittle, and falling off the wires creating other more serious concerns.

Armored cable (AC, MC, or MC-lite) or conduit are, effectively, shielded wiring systems.

--
Give me my freedom, and I'll take care of my own security, thank you.
Re:Focus on ground loops, not on RFI sources. by hankwang · 2004-12-03 05:12 · Score: 1

There are very few guitars with balanced outputs that I know of.
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.

--
Avantslash: low-bandwidth mobile slashdot.
Re:Focus on ground loops, not on RFI sources. by Donkey5555 · 2004-12-03 05:19 · Score: 1

I also had a problem with ground loops on the computer I put in my car (a whine that increased in pitch with the egine speed). I got a ground loop isolator on ebay and the problem completely disappeared. It connects in-line to the audio cable running from my trunk to the head. Maybe something like this could help with your guitar equipment if a ground loop really is the problem.
Re:Focus on ground loops, not on RFI sources. by aaarrrgggh · 2004-12-03 08:03 · Score: 1

The knob and tube can be a problem because of the separation of conductors, not the shielding, but it can definately cause some serious issues with enough harmonic distortion.

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 installed; you don't want the current in the switch leg to form a loop with the neutral.

Last option is to look at your ballasts and make sure they have integral EMI filters. The CF retrofit bulbs won't have anything, but evereything else should be workable. If your problem CF lamps are in downlights, rip them out with retrofit kits. It isn't a horrible project.
Re:Focus on ground loops, not on RFI sources. by Eideewt · 2004-12-03 09:46 · Score: 1

Most guitars are very badly wired themselves, with ground loops and terrible sheilding, and rewiring them can cut a lot of noise.
Re:Focus on ground loops, not on RFI sources. by unitron · 2004-12-03 21:52 · Score: 2, Informative

The average electric guitar has a high-impedance unbalanced (one "hot" one ground) output and the average guitar amp the same kind of input, and the cord in between has a center conductor for the "hot" side and the shield around that is the ground.
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 notorious sources of RF unless you get very special expensive ones.

--
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Re:Focus on ground loops, not on RFI sources. by unitron · 2004-12-03 22:04 · Score: 1

"...a whine that increased in pitch with the egine speed..."
Almost certainly caused by electrical noise from your alternator rather than a ground loop.

--
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Re:Focus on ground loops, not on RFI sources. by Mattcelt · 2004-12-04 05:45 · Score: 1

This is how "balanced" TRS (Tip-Ring-Sleeve) and XLR-type audio cables are supposed to work. Much better than standard mono instrument cable, if your equipment supports it.
Re:Focus on ground loops, not on RFI sources. by pyite · 2004-12-04 06:50 · Score: 1

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.

Uhm. A couple of points. First any microphone with an XLR connector has a balanced output. Second, do you know what a balanced signal is? A balanced line is three wires: one signal, one inverted signal (180 degrees out of phase), and one ground. Simply passing wires through a shield does not a balanced cable make.

--
"Nature doesn't care how smart you are. You can still be wrong." - Richard Feynman
Re:Focus on ground loops, not on RFI sources. by hankwang · 2004-12-04 10:57 · Score: 1

A balanced line is three wires: one signal, one inverted signal (180 degrees out of phase), and one ground. Simply passing wires through a shield does not make a balanced cable.
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 dynamic microphone works. On the other hand, a phantom-powered microphone contains a small buffer amplifier that is connected to ground, so there you don't automatically have a balanced output, unless the buffer amplifier is designed to give a balanced output.
But I admit, I don't know much about guitars. Do they typically have some kind of preamplifier?

--
Avantslash: low-bandwidth mobile slashdot.
Re:Focus on ground loops, not on RFI sources. by Tower · 2004-12-04 15:05 · Score: 1

My brother has an effect pedal for his guitar that is so bad that it actually picks up radio (sounds like shortwave, but it doesn't come in clearly enough that we can tell exactly what.

--
"It's tough to be bilingual when you get hit in the head."
Re:Focus on ground loops, not on RFI sources. by Anonymous Coward · 2004-12-04 18:53 · Score: 0

Since it's an ELECTRIC GUITAR, I'm absolutely certain the inductive pickup in the instrument itself is the primary point where the noise is being introduced.

Sure, he might also have minor ground loop issues, or maybe not! Focusing on ground loops when they might not exist could accomplish little more than improving the "fidelity" of the EMI/RFI noise coming from the pickups! ;-) Believe me. He definitely has ambient EMI/RFI getting into his pickups - it's a fact of life if you play the electric guitar. From my experience, you can switch to a battery powered amp completely disconnected from the grid, and still have the EXACT same problems.

The 60 Hz buzz from ambient EMI/RFI is a major nuisance for electric guitar players... but it can be overcome in many ways, some of them specific to the instrument itself..
(See my post below with the subject of "Many ideas for you.")

Regards,
-The Ruggy
Re:Focus on ground loops, not on RFI sources. by willpall · 2004-12-05 22:47 · Score: 1

The ground loop is what makes the alternator whine apparent. A ground loop acts like an antenna and picks up this noise. Grounding in automotive applications often suffers from this as there can be large voltage drops between the (-) post on the battery and various points on the chassis. At 12V, there is a lot of current running throughout the vehicles electical system, and thus larger voltage drops. I have run into this problem many times when installing stereo equipment. Every time, the solution involved relocating the headunit or the amp ground to a better spot, or even co-locating them.

--
Libertarian: label used by embarrassed Republicans, longing to be open about their greed, drug use and porn collections.
Re:Focus on ground loops, not on RFI sources. by AsbestosRush · 2004-12-06 07:03 · Score: 1

No, not a preamp on completely passive ones, but the signal isn't balanced. Most cheap guitars *do* have crap for wiring tho, and almost all cheap guitars have insufficent shielding to deal with RFI. Hell, even some *nice* guitars suffer from this, but that's neither here nor there.
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 say how it helps, tho. Probably something to do with having 2 coils generating the signal... maybe someone who's an (aspiring?) EE might be able to speak up on it.

--
EveryDNS. Use it. It works.
AC's need not reply
Re:Focus on ground loops, not on RFI sources. by unitron · 2004-12-06 20:36 · Score: 1

Not claiming that good grounding isn't essential, but back in the day car radios grounded through their chassis which were connected at several points to the metal dash which was welded to the car's chassis so the ground path was pretty low impedence and the only inputs were the sheilded cable from the antenna and the +12 Volt power line, so not a lot of potential for ground loops. However inside the radio there was a choke coil for the power line to block the alternator whine that would have traveled in on the power line if not hindered by the high impedence of the choke at the frequency of the alternator whine.
Although I suppose the high side of the car's electrical system could be considered a ground loop if you stretched the definition enough.

--
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Re:Focus on ground loops, not on RFI sources. by drinkypoo · 2004-12-08 04:39 · Score: 1

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 are you producing noise but your alternator is also not producing full output.

--
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Re:Focus on ground loops, not on RFI sources. by unitron · 2004-12-09 19:46 · Score: 1

None of the diodes have to be bad for you to have alternator whine because alternators don't put out flat line DC, it's got lots of ripple, the frequency of which varies with alternator speed.

--
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Re:Focus on ground loops, not on RFI sources. by drinkypoo · 2004-12-10 03:33 · Score: 1

While this is true, and I have even measured it with my scope, alternators usually don't produce serious amounts of noise unless there's something wrong with them.

--
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"

fluorescent lights in the livingroom? by dk.r*nger · 2004-12-02 23:05 · Score: 0, Troll

You have fluorescent lights in your livingroom?

I'm shocked.

Re:fluorescent lights in the livingroom? by GiMP · 2004-12-02 23:22 · Score: 1

They have flourescent lightbulbs at the approximate size and shape of "regular" lightbulbs. I'm using them in my house where-ever I can.

Here is an example of some:
http://www.lightbulbsdirect.com/page/001/CT GY/Mini +Spiral

There are also ones like this, closer to form (via plastic cover)
http://www.lightbulbsdirect.com/page/001/C TGY/CF+F resh
Re:fluorescent lights in the livingroom? by nathanh · 2004-12-02 23:26 · Score: 1

You have fluorescent lights in your livingroom?
I'm shocked.

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? by DieNadel · 2004-12-02 23:35 · Score: 1

I've heard somewhere that fluorescent bulbs has a high UV emission.

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.

--
Utinam logica falsa tuam philosophiam totam suffodiant!
Re:fluorescent lights in the livingroom? by tod_miller · 2004-12-03 00:38 · Score: 1

My Entire Bedroom is fitted with them.

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 32 lcd. Or 32 crt.

Which one?

--
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
Re:fluorescent lights in the livingroom? by walt-sjc · 2004-12-03 01:45 · Score: 2, Funny

Simple fix. Install sunglasses on all your light bulbs. That ought to work...
Re:fluorescent lights in the livingroom? by harrkev · 2004-12-03 02:24 · Score: 1

UV is how they work. UV is emitted, which excites the phosphors (white stuff on the tube) to give off visible light. Without the phosphors, a flourecent bulb would look more like a neon Coors sign.

I think that the glass is supposed to block UV, but I could be wrong. Or maybe the glass is not 100% effective.

--
"-1 Troll" is the apparently the same as "-1 I disagree with you."
Re:fluorescent lights in the livingroom? by DZign · 2004-12-03 02:43 · Score: 1

yes they do, therefor you better don't install them in rooms in which you keep (valuable) collectibles which have paint/color which will fade..
(ie pinball machines in my case)

--
Learn about pinball machines on www.flippers.be
Re:fluorescent lights in the livingroom? by cakefool · 2004-12-03 04:29 · Score: 1

if you have the space and the power doesn't concern you, go CRT

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? by nathanh · 2004-12-03 09:42 · Score: 1

still awaiting your evidence (or retraction)...

Huh, are you stalking me?
http://slashdot.org/comments.pl?sid=130968&cid=109 34611

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.
Re:fluorescent lights in the livingroom? by tod_miller · 2004-12-04 18:58 · Score: 1

On the point of 'big plasma' you could say that any fixed resolution looks bad when scaled too high, but since LCD uses contiguous blocks of LCD, whereas plasma still uses a similar cell structure to CRT phosphor deposits... LCD should win.

is LCD the 'best choice' right now?

I am thinking of CRT, because I chose CRT for my monitor over a cheaper LCD (and now I have to take it back because of red gun issues). I was at first happy, then some gamut issues were annoying me.

Now the size and bulk of it makes me want a nicer LCD, even for programming and web development.

There is an offer for a 42" plasma and 30" LCD locally for around 3000EURO - which seems unbelievable.

Must resist urge, oh and it will be running MythTV through an RF connection to my PC. hell yeah!

--
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
Re:fluorescent lights in the livingroom? by bbuR_bbuB · 2004-12-08 09:15 · Score: 1

Why would you ever do that? Flourescent lights give off some of the worst light, in my opinion. Why would you want everything to look that weird shade of green?
Re:fluorescent lights in the livingroom? by GiMP · 2004-12-08 15:36 · Score: 1

Because the bulbs last longer and use less energy.
Re:fluorescent lights in the livingroom? by bbuR_bbuB · 2004-12-10 08:20 · Score: 1

How much energy is used to create the flourescent bulb vs. an incandescent one? What about toxic materials that were used to make the lightbulbs or may ven lurk inside (plastics, etc)? There's more to the energy equation than what your electric company bills you. You're just offloading the costs (financial, environmental) of the flourescent bulb onto the community in which they are manufactured and the community in which they will be disposed.

Flourescent lighing by madaxe42 · 2004-12-02 23:09 · Score: 2, Interesting

Flourescent lighing is inherently noisy - it essentially relies on a large oscillating rf field in a mercury vapor filled tube - no matter what you do, it'll produce noise, electrical from the field, and audible from the tube resonating with the field.

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 by madaxe42 · 2004-12-02 23:19 · Score: 1

Flourescent lighting - for when you can get enough of that wheaty smell! mmmmm flour....
Re:Flourescent lighing by silverfuck · 2004-12-03 00:51 · Score: 1

mercury vapor filled tube

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.

--
You know you've been IMing too long when you almost say 'lol' out loud to a non-geeky friend...
Re:Flourescent lighing by rot26 · 2004-12-03 01:53 · Score: 1

Perfect solution, except for the price. You'd have to take out a second mortgage on your house to buy enough of them to be effective.

--

To ensure perfect aim, shoot first and call whatever you hit the target
Re:Flourescent lighing by josecanuc · 2004-12-03 02:08 · Score: 1

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.

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
Re:Flourescent lighing by madaxe42 · 2004-12-03 02:12 · Score: 1

Fluorescent tubes are mercury vapor - they rely on excitation and emission of mercury vapor, and a mercury oxide coating on the interior of the tube, which fluoresces at a white light frequency - mercury vapor lamps operate at higher voltages, and work on a direct excitiation principle - like sodium vapor lamps.

Interferometry lab. Mmmmmm. Prisms... So glad I finished my phys degree last year.
Re:Flourescent lighing by DAldredge · 2004-12-03 02:51 · Score: 3, Informative

he following introduction is from a publication by the National Electrical Manufacturer's Association (NEMA) entitled "Fluorescent Lamps and the Environment". This publication and a lot more valuable information can be found at the NEMA website devoted to proper lamp disposal called www.lamprecycle.org. An Adobe Acrobat PDF version of the publication can be downloaded from www.nema.org/lamprecycle/nemafluorfinal.pdf

If you need more information about properly disposing of lighting waste click on the link at the left for "lamp disposal rules".

Why Do Lamps Need Mercury?

"Mercury is an essential ingredient for most energy efficient lamps. Fluorescent lamps and high intensity discharge (HID) lamps are the two most common types of lamps that utilize mercury. Fluorescent lamps provide lighting for most schools, office buildings, and stores. HID lamps, which include mercury-vapor, metal halide, and high- pressure sodium lamps, are used for street lights, floodlights, and industrial lighting. A typical fluorescent lamp is composed of a phosphor coated glass tube with electrodes located at either end. The tube contains mercury, of which only a very small amount is in vapor form. When a voltage is applied, the electrodes energize the mercury vapor, causing it to emit ultraviolet (UV) energy. The phosphor coating absorbs the UV energy, causing the phosphor to fluoresce and emit visible light. Without the mercury vapor to produce UV energy, there would be no light. A four-foot fluorescent lamp has an average rated life of at least 20,000 hours. To achieve this long life, lamps must contain a specific quantity of mercury. The amount of mercury required is very small, typically measured in milligrams, and varies by lamp type, date of manufacture, manufacturing plant, and manufacturer."

"If lamp life is shortened, more lamps must be purchased to achieve the same length of service, and the number of lamps that generators must dispose will increase. How Much Mercury Do Lamps Contain? Based on a 1999 NEMA survey, the average four-foot fluorescent lamp contains about 11.6 milligrams (mg) of mercury. This number has been steadily declining as lamp manufacturers work to reduce mercury content to the minimum amount technically feasible without reducing lamp life. The average four-foot lamp today contains over 75% less mercury than the same lamp would have contained in 1985. According to the U.S. EPA, total global natural and manmade emissions to the environment are 5,500 tons. 1 Manmade sources in the U.S. released 158 tons of mercury in 1995. For comparison, all of the lamps sold in the United States in 1999 containonly an estimated 13 tons of mercury, of which only a fraction will be released as an air emission. Proper lamp disposal or recycling will result in keeping almost all of this mercury out of the environment."
Re:Flourescent lighing by Anonymous+Cowdog · 2004-12-03 04:50 · Score: 1

>You'd have to take out a second mortgage...

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 by rot26 · 2004-12-03 06:50 · Score: 1

Sorry, I wasn't very clear there. I was referring to replacing the bulbs with LED arrays. They're hideously expensive.

--

To ensure perfect aim, shoot first and call whatever you hit the target
Re:Flourescent lighing by Anonymous Coward · 2004-12-06 05:42 · Score: 0

Wow, amazing display of ignorance there, bub. Are you the janitor at this "interferometry lab"?
Re:Flourescent lighing by silverfuck · 2004-12-06 05:50 · Score: 1

Lol, no, just a student busy failing my degree. I can see why now! :-P

--
You know you've been IMing too long when you almost say 'lol' out loud to a non-geeky friend...

RFI Solutions by Ed+Almos · 2004-12-02 23:19 · Score: 5, Informative

As a radio ham I have similar problems, try the following.

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

--
The more corrupt the state, the more numerous the laws. - Tacitus, 56-120 A.D.

Re:RFI Solutions by tod_miller · 2004-12-03 00:36 · Score: 2, Funny

[geek awe]

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]

--
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
Re:RFI Solutions by peragrin · 2004-12-03 01:54 · Score: 2

No but I am using a pringles can to my neighbors unprotected access port, even though i have my own cable connection.

--
i thought once I was found, but it was only a dream.
Re:RFI Solutions by Anonymous Coward · 2004-12-04 11:55 · Score: 0

Try here
http://www.arrl.org/catalog/index.php3?categ ory=In terference%2FDF

73
de
N8JUC

Cables? by metatruk · 2004-12-02 23:24 · Score: 1, Insightful

Are you using good audio cables? for example, balanced instead of unbalanced? Are you using good quality connectors?
Is all of your equipment properly shielded and grounded?
These would be the first things I'd check.

Re:Cables? by duffbeer703 · 2004-12-03 02:12 · Score: 1

Do you work at best buy? Sounds like you're hocking those $5,000 Monster cables...

--
Conformity is the jailer of freedom and enemy of growth. -JFK
Re:Cables? by GoRK · 2004-12-03 03:42 · Score: 1

Overpriced cables like monster are a stupid waste of money, but he did not hawk a brand there. You can't just wire everything up with unshielded 24awg wire and expect to get away with it. Proper cabling is very important in any setup - phone, video, electrical, audio, etc. A lot of the cheap cables really are cheap and do not do a good job of eliminating interference. Good connectors are important too. I ran into the connector problem when wiring the coax for cable tv in my last house. I got decent RG-6U coax, but skimped on the connectors. I had a heck of a time getting a good signal with a modulator in the high frequency catv ultra-band (channels 88-96) despite using a bandpass filter, etc. Good termination (along with a power filter on the CATV amplifier) would have most likely alleviated this problem.

If you want good cables at fair prices, check out Blue Jeans Cable or something similar. They won't try to sell you some special $30 "modem cable" or $40 USB cable like best buy/monster cable either.
Re:Cables? by Technician · 2004-12-07 19:25 · Score: 1

Have you seen any guitar outputs that used a balanced XLR connector? Have you seen a guitar amp with balanced XLR inputs?

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.

--
The truth shall set you free!

How about... by Hank+Reardon · 2004-12-02 23:28 · Score: 1

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.

--
There's so little difference between politics and jihad lately...

Re:How about... by Technician · 2004-12-07 19:29 · Score: 1

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.

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.

--
The truth shall set you free!
Re:How about... by Hank+Reardon · 2004-12-08 05:36 · Score: 1

You've got to admit, though.... Tinfoiling the walls would be much more fun!

--
There's so little difference between politics and jihad lately...

Install dual lighting systems. by OneDeeTenTee · 2004-12-03 00:02 · Score: 1

Use the fluorescent fixtures when you don't care about interferance and the incandescent ones when you're recording.

--
Stop the world; I need to get off.

Simple Solution by liqnitro · 2004-12-03 00:39 · 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, 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 by antifoidulus · 2004-12-03 00:41 · Score: 1

Candles!

--
Monstar L

Ditch the dimmers. by david.given · 2004-12-03 00:45 · Score: 3, Informative

Trying to dim fluorescent lamps is a really problematic process; see here for a discussion. You can't dim them by reducing the voltage, and have to pulse the power supply instead. This will, as you have discovered, interact oddly with the ballast and the tube itself and is probably what's making the bulk of your radio noise.

(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? by VernonNemitz · 2004-12-03 00:59 · Score: 2, Informative

Get some wire mesh and surround each light fixture with it, and "ground" the mesh. The size of the mesh-holes will depend on the frequency of the interference (higher freq -> smaller mesh). Chicken wire is fine for some things (60-cycle AC hum) and window-screen mesh might be needed for others (but associated with lessened lighting, alas). If you can find mesh with holes as large as those in a microwave-oven door, that will probably be more than small-enough. (Of course, if this is really a good idea, then I expect some comment from some expert who KNOWS exactly what size of mesh is sufficient. :)

Re:How about Faraday Cages? by hankwang · 2004-12-03 05:45 · Score: 1

Get some wire mesh and surround each light fixture with it, and "ground" the mesh.
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 block the magnetic component of the field, because that is the one that will generate currents in wires, similar to what happens in a transformer. Blocking the magnetic component is hardest for the low frequencies. I guess you'd need a couple of millimeters of solid metal for that, comparable to the amount of copper that is sitting around the core of a transformer.

--
Avantslash: low-bandwidth mobile slashdot.
Re:How about Faraday Cages? by VernonNemitz · 2004-12-03 06:12 · Score: 1

Regarding the near field, that's something I didn't know. But what about the fact that chicken wire and window-screen wire is often made of steel? Your post implies a copper mesh. Magnetic fields don't usually pass through a surrounding layer of iron/steel, and steel, while not as good a conductor as copper, is nevertheless conductive enough to ground induced milliamps. Or am I missing something else?
Re:How about Faraday Cages? by hankwang · 2004-12-03 07:22 · Score: 1

But what about the fact that chicken wire and window-screen wire is often made of steel? Your post implies a copper mesh. Magnetic fields don't usually pass through a surrounding layer of iron/steel, and steel, while not as good a conductor as copper, is nevertheless conductive enough to ground induced milliamps.
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. However, iron is too slow to block higher frequencies. That is why a line transformer at 50/60 Hz uses an iron core, while the transformer in a computer power supply, which runs at a few 10s of kHz, uses a ferrite core.
Good EMF shielding is a kind of voodoo science and I don't claim to know it all. But in the lab, I have never succeeded in blocking RF interference by just wrapping cables in aluminium foil. I would guess that a thick sheet of iron will block low-frequency magnetic fields, as well as high-frequency electric fields, but it would be pretty expensive to build a whole room like that, and then still you need somehow to power your equipment.

--
Avantslash: low-bandwidth mobile slashdot.
Re:How about Faraday Cages? by VernonNemitz · 2004-12-03 07:35 · Score: 1

OK, then I guess the key question is, What Frequency do those fluorescent ballasts run at? Because that's the frequency we want to shield. I wouldn't be surprised if it is more than 60Hz (yet that would be my first guess, especially for older-model straight-tube fluorescents), but I would be surprised if it was more than, say, 250Khz, even for the newer incandescent-replacement devices, with convoluted glass tubing.

Maybe all the guy needs is a Faraday Cage surrounding himself and his recording system....
Re:How about Faraday Cages? by DeComposer · 2004-12-03 09:37 · Score: 2, Informative

As I recall, flourescent light ballasts double the line frequency (presumably using a tuned resonant filter--I'd guess an LC tank) to 120 Hz (or perhaps some other multiple of 60 Hz). BTW, Electromagnetic interference in this frequency range is not in the radio frequency (RF) range (ELF transmissions notwithstanding); its correct designation is "EMI".</nit>

Now for the bad news:
a surprisingly vast amount of professional audio gear uses 1/4" unbalanced connectors. Of the synths, samplers, and effects processors in my studio, maybe a quarter of them have balanced outputs. (The mixers, of course, have balanced line and balanced mic inputs and outputs). This means I have to spend considerable effort routing cables to minimize 60 Hz inductance from power cables. The inverse-square law applies in this case: the farther audio lines are from power lines, the better 60 Hz line noise is rejected. In situations where proximity between the two is unavoidable, I try to cross them at 90-degree angles to minimize inductance.

Getting back to your question...
For myself, a music studio is primarily an auditory experience; I don't want a lot of bright light. Reflections on device displays or monitors are distracting and detract from my enjoyment of working in the studio. Plus, when I have other musicians or clients in the studio, I want them to focus on the music, not their visual surroundings. My solution is to use low power (25-40W) incandescent fixtures, usually aimed at walls or ceilings to provide soft, indirect lighting. (If I need to work from a score or other paper material, I'll us a task light.) This solution provides more than adequate light to find my way around in the studio without running into things and creates a warm working environment, all without sucking down huge gobs of electricity.

Incidentally, I have sometimes wondered if tight twisted-pair cables would help with EMI rejection for audio the way it does for data transmission (i.e. ethernet over CAT5). I welcome the thoughts of any EEs out there with some experience in this area.

--

Karma
Re:How about Faraday Cages? by Anonymous Coward · 2004-12-05 18:28 · Score: 0

Umm... for this Faraday cage idea to work, the target to be protected has to be INSIDE the cage. Placing the SOURCE of the interference inside the cage doesn't help all that much...

Fluorescent lighting in a recording studio? Gah! by jonadab · 2004-12-03 01:23 · Score: 1

> 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.

There are two places where fluorescent lighting really doesn't belong: a
recording studio is one of them. (The other is a room with a lot of CRTs,
because the flicker can reach epilepsy-inducing levels.)

> 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.

Yeah, they do that.

> Barring replacing all my fixtures and lamps with conventional incandescents,

Okay, don't replace all of them then. How about just the ones in the most
strategic places, such as near the recording equipment? Oh, and the ones
you don't replace, make sure they're on a separate electrical circuit from
the electronic equipment. (Lighting should generally be on a separate
circuit from outlets anyway... but fluoresent lighting should definitely
be on its own circuit.)

> 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!

Fluorescent lights have always been that way. I've never seen a fluorescent
light that didn't emit audible sound. Different ones have different pitches,
and some are more ignorable than others, but they're all quite audible.

> 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)."

It is conceivable that not all of the interference is coming through the
air (and therefore largely unblockable without blocking the light) -- some
of it may be coming to the sound equipment via the power cables. It might
be worth a try to put the sound equipment on a power-conditioning UPS, the
kind with sine-wave output. This is expensive, significantly more expensive
than incandescent lamps (though, depending on how integrated the fixtures
are into the building, probably still cheaper than replacing all your
fixtures), but it *might* work, or at least help. Still, I'd get at least
one incandescent lamp (a desk lamp will do in a pinch) for right next to
the sound equipment, and switch off any fluorescent light that's right there.

--
Cut that out, or I will ship you to Norilsk in a box.

have you asked yourself the basic question... by Khyron · 2004-12-03 01:57 · Score: 2, Insightful

...just how much are these flourescent lights saving you?

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. Let's talk about you.

How much money are you really saving using these? You're setting up a home recording studio. I bet a couple of your cables alone, save any of your equipment, costs you more than these lights will save you over several years.

I think you'll find that in your case, you can be a lot more effectively frugal and environmentally friendly by worrying about a properly tuned digital thermostat or improved insulation and HVAC in your older house than saving any real money with these lights, which are fundamentally incompatible with your hobby.

Re:have you asked yourself the basic question... by JabberWokky · 2004-12-03 05:28 · Score: 1

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. Let's talk about you.
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

--
"$30 for the One True Ring. $10 each additional ring!" -- JRR "Bob" Tolkien

Wow... some savings by duffbeer703 · 2004-12-03 02:22 · Score: 1

Energy saving bulbs don't save you money.

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 install incandescent or halogen lighting (like GE Edison bulbs)

--
Conformity is the jailer of freedom and enemy of growth. -JFK

Re:Wow... some savings by cdrudge · 2004-12-03 04:55 · Score: 1

They are energy saving bulbs. Meaning that they save energy, not necessarily money. They also don't run nearly as hot so can further reduce the thermal load on air conditioners, but they don't help heat in the winter either.

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 a CF lightbulb is around 10,000 hours @ $10 a pop. Incadescent is around 1,000 at $.50 for a good quality name brand bulb. So you need 10 over the lifetime, costing 1/2 the price of a CF bulb, however the CF only draws 1/4 the power for equivilent output.
Re:Wow... some savings by Anonymous Coward · 2004-12-08 08:45 · Score: 0

What are you all smoking?
I buy CF bulbs at Costco that are 13W, and they come in 15 packs for about $18

That's easy! by Datoyminaytah · 2004-12-03 03:50 · Score: 2, Funny

> ...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). Well, that's easy! Just make your money by playing your guitar. When you figure out how, be sure to let me know. :)

--
assert(birth_date<time-86400)

White light *frequency*? by Engineer-Poet · 2004-12-03 03:58 · Score: 1

White light is a spectrum of frequencies; any one frequency is called "monochromatic".

--

Sustainability and energy independence essay

Know what you're doing! by Engineer-Poet · 2004-12-03 04:11 · Score: 1

If you are going to mess with line current, chokes or anything of the sort, you should know enough to know what component types and values to use, how to connect them safely and how to package them so that they will not exceed their temperature, voltage or other limits in operation.

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... but if you have little expertise you're going to have a lot of trouble telling the good from the bad. Especially don't go off based on vague suggestions like this:

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.

If you wire a 5000 microfarad cap across the AC line, your life may get more interesting than you want - it will pull current (perhaps enough to overheat and blow the capacitor) and the high inductance of such a large capacitor will make it a poor bypass for RF emissions. You will want what are known as disc ceramic capacitors rated for several hundred volts (they have to endure line spikes) and with values chosen for the RF frequencies you are trying to get rid of.

Last, the light itself may be radiating enough to bother you. There are probably ways to bypass radiated emissions from a circle tube, but I have not heard about them nor have I investigated the issue.

--

Sustainability and energy independence essay

Re:Know what you're doing! by Ed+Almos · 2004-12-03 05:10 · Score: 1

Agreed, somebody carrying out these modifications should know what they are doing, but I think my post and your reply requires some clarification.

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 volts AC and is self healing with an epoxy case. It has a value of 0.22mfd, somewhat bigger than your 5000mfd example .

Finally (and I agree with you again) anybody carrying out work like this should know what they are doing, be aware of the required rating of any components used, and be aware of the dangers. Being roasted in your own body fat whilst connected to a 110 volt line is not a nice way to die.

Ed Almos
Budapest, Hungary

--
The more corrupt the state, the more numerous the laws. - Tacitus, 56-120 A.D.

Simple Tips by delus10n0 · 2004-12-03 04:23 · Score: 1

1) Run a seperate ground/power block, just for your recording studio.

2) Make sure your equipment itself doesn't have ground loops. Check out this video on TaylorGuitars.com about the importance of a good ground.

--
Not All Who Wander Are Lost

Re:Simple Tips by TheHawke · 2004-12-03 14:35 · Score: 1

Can't do that, NEC electrial code prohibits installation of a 2nd ground spike for household systems. This creates what is called a floating ground, effectively causing a major shock hazard.

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.

--
First rule of holes; When in one, stop digging.

Simple solution? by menscher · 2004-12-03 04:23 · Score: 1

Disclaimer: I'm a /. reader. This could be completely wrong.

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.

Re:Simple solution? by Anonymous Coward · 2004-12-04 18:01 · Score: 0

Electric guitars have inductive pickups that are extremely sensitive to RFI/EMI waves traveling though the aether.

For a real susprise, activate a cell phone near an amplified electric guitar! Especially a digital phone... "ZAP ZAP ZAP ZAP!"

-The Ruggy

I guess you've never toted them up. by Engineer-Poet · 2004-12-03 04:25 · Score: 3, Informative

I use a bunch of circle-tube CF's installed in table lamps. They are rated at roughly the same light output as a 150 W incandescent but they use only 34 watts on full (they're 3-way). They will run at least a year between tube replacements and these units cost about $20 new. Figuring 2000 hours of operation @ 34 watts and 8 cents/KWH and $20 up-front, the total cost for those 2000 hours is $25.44. That's assuming that you have to throw away the whole lamp after 2000 hours instead of just replacing the circle tube; if you replace the tube every 2000 hours at $5 each the cost for each incremental 2000 hours goes down to $10.44.

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.

--

Sustainability and energy independence essay

Re:I guess you've never toted them up. by karnal · 2004-12-03 07:41 · Score: 1

"Lifespan of a 150-watt incandescent is what, 200 hours or less? "

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....

--
Karnal
Re:I guess you've never toted them up. by Engineer-Poet · 2004-12-06 02:53 · Score: 2, Informative

I just replaced a tube over the weekend (2-3 years on that tube) and checked the new GE 3-ways at the hardware store. They claim 10,000 hours on a tube for about $25 (not a big-box store, prices are higher). The 150-watt 3-way incandescents across the aisle were $2.29 and claimed 2000 hours. Figuring 33 watts for the GE going flat-out, over 10,000 hours it will use 330 KWH at a cost of $26.40 for a total cost of $51.40 sans taxes. The 5 incandescents would cost $11.50 in toto and use 1500 KWH at a cost of $120 for a total of $131.50.
It looks like the CF saves about $80 on the first tube and, at a replacement cost of $9.00 per tube, $96 on each subsequent tube. Not bad, eh? Oh, these are 3-way ballasts, a simple one-way on/off would be about $10 cheaper these days.

--

Sustainability and energy independence essay

Do the math! by redelm · 2004-12-03 04:34 · Score: 1

Power at $0.12/kWh:

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.

you said its an old house... by luvbassonacid · 2004-12-03 04:47 · Score: 1

...so i cant imagine the wiring being any good. check that everything is properly grounded. go to radioshack and buy yourself one of those miltimeter\electriction tool sets that have the modified plugs you stick into the walls, usually they have little LED's that let you know if the socket is even grounded at all. its also important to make sure that your audio equipment does NOT share a common ground with everything else in your house. this would call for a wirering overhaul. most of the studios i have worked in have two different sets of color coded wall outlets, one for audio gear only, another for everything else.

although this point may be redundent, try to use balanced cables wherever possible. and try and get the best quality imaginable for the cables that MUST be unbalanced (e.g. guitar outs to the amp.)

as for the lights, i think in a studio situation you would have to eliminate all possible sources of noise, whatever the cost. the point of this studio is to get the best possible sound. period.

also, are you running any audio wires under rugs or against walls or something? this can be bad since your electricity wiring is right behind the walls\floors. NEVER have ANY audio cables next to or within a few feet of electrical wiring. i have seen people wrap up their amp\head electrical wireing along with their D.I. box\mic cables and wonder why they keep blowing out their cabinets.

well basically what i want to say is to kind of to agree with Hackwang's comment that "The best way to avoid RF interference is not to remove all RF sources, but to design the electronic circuits correctly." i both agree and disagree with that statement, basically if your getting RFI so bad that you cant even play, i think the lighting is the least of your worries, the wireing is ultimatly the culprate, because if wasent the lamps making the noise it would have been somthing else at a later date. however if you fix the wiring, put in multiple grounds, dedicated audio circuts AND get rid of all noise makers, RFI or acoustical, then you will definetly be on your way to a better sound.

then we would have to talk about mics, pre-amps, and the acheivement of total acoustic isolation...

--
--- Why rant when you can rave?

Re:you said its an old house... by Anonymous Coward · 2004-12-04 00:50 · Score: 0

Better have the professionals install another ground if it comes to that. There are other potentially very nasty things to consider. You can do things like greatly accelerate corrosion of near by pipes, water, gas.

this might not be useful by ivano · 2004-12-03 05:12 · Score: 1

but the dimable lighting you havemight have to do with the transformer. You should be getting a loud humming noise when you turn on those lights.

A fix would be to get a "shielded" tranformer.

MOD PARENT UP !!! by Anonymous Coward · 2004-12-03 05:57 · Score: 0

Sensible, obvious solution.

Re:MOD PARENT UP !!! by OneDeeTenTee · 2004-12-03 13:09 · Score: 1

Sensible, obvious solution.

Why would anything like that ever get modded up?

You must be new here.

--
Stop the world; I need to get off.

Once again.... by Engineer-Poet · 2004-12-03 06:20 · Score: 1

The X2 rated capacitor I am looking at now is rated to 275 volts AC and is self healing with an epoxy case. It has a value of 0.22mfd, somewhat bigger than your 5000mfd example .

Bigger? Try about 1/22500 of the size.

--

Sustainability and energy independence essay

Re:Once again.... by slazar · 2004-12-08 19:19 · Score: 1

Child genius to Bart: Tell you what, Bart, I'll trade you the weight of a bowling ball on the eighth moon of Jupiter for my lunch, for the weight of a feather on the second moon of Neptune from your lunch. Another child genius to Bart: I'll trade you 1000 picoliters of my milk for 4 gills of yours.

Interference through the power lines??? by hankwang · 2004-12-03 06:21 · Score: 1

I'd guess that the interference is coming in through the power lines.

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 230 V country, try putting your PC into an ungrounded wall outlet and touch the PC chassis simultaneuously with the ground pin of a wall outlet. Bzzzt! 115 V on the chassis. (The current is not big enough to kill you, but it's quite unpleasant)

--
Avantslash: low-bandwidth mobile slashdot.

Buy an online UPS by ponos · 2004-12-03 07:02 · Score: 2, 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

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 by LyingDown · 2004-12-03 09:56 · Score: 1

An alternate to online UPSes, usually less expensive: a line conditioner. Tripp Lite sells some good but inexpensive models: http://www.tripplite.com/products/conditioners/tra nsformers.cfm their 500VA unit runs about $150 (I have NO idea how much power the OP's equipment pulls).
Re:Buy an online UPS by ponos · 2004-12-04 01:08 · Score: 1

their 500VA unit runs about 150$(I have NO idea how much power the OP's equipment pulls).

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 specifically designed for audio equipment. Such conditioners may simply protect sensitive components from relatively major fluctuations but in this case minor fluctuations can be significant.
P.
Re:Buy an online UPS by lachlan76 · 2004-12-07 17:34 · Score: 1

Or you can make something like this.

and labor... by way2trivial · 2004-12-03 08:40 · Score: 1

the value of your time, purchasing, and installing, and disposing of the bulbs...

--
every day http://en.wikipedia.org/wiki/Special:Random

Energy saving bulbs don't save energy by tengwar · 2004-12-03 09:51 · Score: 1

... well, at least in cold climates they don't. The point is that 100% of the energy consumed ends up as heat, and all but that which gets out of the windows as light stays in the house. If you get a bulb that uses less power, your heating system has to consume more fuel to maintain the same temperature.

Re:Energy saving bulbs don't save energy by Webmoth · 2004-12-03 18:38 · Score: 1

I am agreeing with you, BUT it may be that in his locale, it's cheaper to heat with another source of energy such as gas, coal, oil, kerosene, gasoline, jet fuel, hydrogen, or anhydrous ammonia than it is to heat with electric lighting fixtures.

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, requiring the heating system to make up the difference.

So does the acoustic energy produced by his monitor speakers.

I do like the idea of one poster who suggested using flourescent for day-to-day living, and switching to incandescent when using the audio equipment.

Since I'm rambling on, I might as well say something about the audible noise of flourescents: if a fixture is particularly noisy, it's probably using a magnetic ballast which has a loose winding. Replacing the ballast either with a new magnetic one or an electronic one should quiet it down (the electronic one will require changing out the tubes, too).

As the parent poster stated that he lives in an old house, he will realize a greater return on investment -- and significantly lower energy use -- by sealing and insulating his home if it is not already.

--
Give me my freedom, and I'll take care of my own security, thank you.
Re:Energy saving bulbs don't save energy by bitingduck · 2004-12-04 07:42 · Score: 1

I do like the idea of one poster who suggested using flourescent for day-to-day living, and switching to incandescent when using the audio equipment.

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 interference, and you just need to keep the transformer away from anything that will pick up from it. You can get them at ikea (but some are a PITA to install) or probably a lot of other places at relatively low cost. Much better mood lighting for music than using fluorescents anyway.

(much like the OP, I have fluorescents installed in most fixtures in my house, too. The main thing I use incandescents for is keeping plants warm on really cold nights).

Halogen by Supernoma · 2004-12-03 17:38 · Score: 1

What about switching everything over to halogen lighting? Or LED's?

--
I'll Find You Peer, If It's The Last Thing I Do!!!!

Fix the leaks before tweaking the system by Webmoth · 2004-12-03 18:46 · Score: 1

Before investing a lot of money in reduced-energy lighting, you should (have) spent it on insulation for your "very old" house.

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 if the gas tank leaks you'd better fix that first.
Same thing goes with your house -- fix the leaks before tweaking the system.

--
Give me my freedom, and I'll take care of my own security, thank you.

The downside by macemoneta · 2004-12-04 03:59 · Score: 1

Remember that all the solutions to powerline noise will also block powerline transmission of data. If you were thinking of using X10, power line networking, or any other transmission over the power lines it will be blocked.

That's not necessarily a bad thing, unless you've already invested in this technology. :-)

--

Can You Say Linux? I Knew That You Could.

Simplify things. by adolf · 2004-12-04 16:10 · Score: 1

In my studio, the only noise problems we ever had were the sounds of a road a block away being picked up by the microphones when enormous amounts of gain were in use. In other words, it was electrically very quiet.

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 cheap at Wal-Mart. Wattages varied.

Grounding was sensible and straightforward from the start. We never encountered hum.

In the beginning, we were using common rheostat dimmers in a few spots, but quickly found that it was a big pain in the ass. They'd cause the lights themselves to audibily sing at most dim levels, and were thus absolutely no fun to use. All of these got replaced with 50-cent on/off switches.

In most sessions, the only time there was more than a couple of hundred Watts of lighting in use was when people were moving gear around, or cleaning. Generally speaking, the musicians sounded better with only a few lights turned on.

I can't imagine attempting to intentionally use anything electrically noisey in a studio enviroment.

Shielding and proper grounding can eliminate a lot of the stuff that's floating around in the air. Ferrite chokes might help a little on the AC lines going to both your lighting and your gear.

But even if you're using big, spendy ferroresonant transformers (think Best FerrUPS), an on-line UPS (so that your gear is running from its own inverter), or a motor-generator (look, ma, a flywheel!) you're just treating the symptoms, not the problem.

In doing so, you'll -still- have EMI floating around, plus at least one more accoustically noisey apparatus to keep away from the microphones.

And every guitarist who walks through the door with an instrument using single-coil pickups will be pulling his hair out as he tries to figure out why his rig is suddenly noisey as hell, while it was perfectly quiet before he left home. And then you'll both spend a lot of time trying to make it quiet before you can even think about laying down any tracks.

Both you and he have better things to worry about than whether or not his guitar rig is wired "correctly" (whatever that is), or if your fancy dimmable fluorescent fixture is on the fritz again, or if maybe his amp got damaged in transport, or if maybe there's a bad wire somewhere, or...

These discussions should never have to happen - he's there to play music, and you're there to record it. Anything that complicates that arrangement is something which will, in some way, stifle the creative process and will result in a recording which could've been better.

Therefore, the solution to your problem is to remove the problem. Simplify things. Move the CF lights to your home's livingspace (away from the studio), and trash the dimmable fluorescents. Develop a creative lighting system which allows you to flip a few switches to make things look and feel good, instead of developing a complicated system to let you survive with noisey light fixtures.

If you're unwilling to do this, be prepared to spend more time/money fixing things that shouldn't have been broken to begin with than you'll ever save on your electric bill by using more efficient lighting.

--
Kid-proof tablet..

MANY ideas for you! by Anonymous Coward · 2004-12-04 17:24 · Score: 1, Informative

If you use one single-wound pickup, of you will have hum from any RFI/EMI in your vicinity.

But there are alternatives... "Humbuckers" for example are like two pickups right next to each other wired in such a way as to cancel the hum.

(Personally I don't play music that sounds good on humbuckers... but YMMV.) There are other options too.

If you use a G&L "Z" pickup, these are like two half-pickups for three strings each, and they're wired in a humbucking configuration. These are an excellent design, IMHO.

Another great option is to use two single pickups and have them wired in a humbucking configuration. My G&L ASAT 2000 (basically a Telecaster) has a pickup switch with three positions. I can select Front, Rear, or Both pickups wired together in a humbucking configuration... which is the configuration I usually play in. It gives the right amount of treble from the rear pickup with all of the rich tones from the forward pickup, without any RF hum, and with a far richer tone than could be generated with your typical humbuckers.

If your current guitar doesn't provide this option, you could talk to a repair shop or if you're up to it, maybe get out your soldering iron... (You always wanted a custom guitar, right?)

In addition to the above, you should try putting your noisy lamps on power strips that have RF chokes in them! Some power strips advertise EMI/RFI filtering.... those are the kind to get.

If that doesn't help, try winding the cord of each of your lamps into loops of say, 3 or 6 inches in diameter. Clamp a ferrite bead around one part of the ring.

Okay now for the serious voodoo... and don't laugh until you've tried this, because it actually can work. I have used the following trick many times:

Get a long extension cord and plug the lamp or lamps into the cord. Wind the extension cord into a circle on the floor maybe 2 or 3 feet in diameter. Experiment with increasing or decreasing the number of turns in the coil, and also with the direction of the winding (flip the coil over.) You should find that this has an effect on the amount of hum which reaches your guitar's pickup. Through trial and error, you may be able to reduce it substantially by this method. Basically what you're doing is creating a variable RF choke with the extension cord. It works on microphone cables too.

By combining the above methods, you chould be able to win the battle against EMI/RFI without having to construct a Faraday cage to play in. ;-)

Best of luck!!
-The Ruggy

Re:MANY ideas for you! by Anonymous Coward · 2004-12-04 17:33 · Score: 0

FYI... Here's a clampable ferrite bead. This one is small but you could try just clamping it over the lamp cord. It would likely have a noticeable effect.

-The Ruggy

Balanced power by stinkydog · 2004-12-04 17:28 · Score: 1

You could hook up one of these fancy balanced power systems. The National Electrical Code has the basic details. Unfortunatly, these are not cheap. The bargain solution is to get some nice incandescent table or floor lamps and use them when you record.

--
âoeWho knew something as harmless as willful ignorance could end up having real consequences?â

Ground Loop Isolator by Poindexta · 2004-12-04 17:33 · Score: 1

I had a similar problem in a home recording studio and fixed it using a Ground Loop Isolator. I have heard rumors that they can slightly degrade the quality of an audio signal, though I have also read that it doesn't matter because it is impossible for a human to discern the difference in audio quality. In my experience the fact that it so effectively kills any buzz/humm means that it is improving the quality of the audio signal. Here's the website for the manufacturer of the one I use:

http://www.xiteldirect.com/home.htm

They are also available at Radio Shack and from some other vendors but I only have experience with the Xitel model.

In the interests of science... by tod_miller · 2004-12-04 18:55 · Score: 1

Original, Sour Cream & Onion, Sweet Mesquite BBQ, Cheezums, Pizzalicious, Spicy Cajun, Salt and Vinegar, Cheese & Onion or Ranch-Rageous?

--
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com

Re:In the interests of science... by peragrin · 2004-12-05 02:17 · Score: 1

Sweet Mesquite BBQ of course, the other flavors only taste good when very drunk

--
i thought once I was found, but it was only a dream.

Things I probably should have mentioned... by amper · 2004-12-04 19:42 · Score: 1

I couldn't reply sooner because I've been on the road working on a large project halfway across the country...

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, there is a significant amount of Knob & Tube wiring in my house. In fact, most of the lighting is running on the old stuff (two circuits for the whole four floors, actually). There are some newer circuits installed, which is where all the expensive audio gear is plugged in.

3. All of the actual recording gear is running with balanced cabling, with proper signal and chassis grounding (as far as I can tell). The noise is being introduced mostly through the unbalanced signal cables in my guitar and bass rigs (though the bass rig is all balanced once it hits the preamp).

4. No, I haven't bothered to attempt to improve the shielding of my guitars. I know I should do this. I've had problems at gigs because of this, but pulling apart an expensive instrument and shielding all the electronics cavities is an expensive and time-consuming proposition that can actually damage the resale value of the intstrument (crazy vintage gear collectors! Arrgh...).

5. I have replaced most of the compact fluo bulbs with regular 40w or 60w bulbs. It *has*helped, of course, but some fluo fixtures remain that are definitely not grounded properly (they're all on two-wire power).

6. The reverb circuit in my Mesa/Boogie F-50 combo picks up an amazing amount of RFI when I switch it on. Perhaps replacing the driver tube might help? I'm not sure...

7. Ground loops are fairly easy to detect and usually result in relatively loud hum (or odd oscillations in tube amps). Most of my problem is related to the lighting on the older circuits.

8. No, I can't afford to pull apart all the walls and re-wire the whole house. After all, I've recently spent a whole bunch of money on a new G5 and recording equipment. It *will* be done eventually, though, along with insulating the walls properly.

9. Yes, the incandescents do help heat up the place now that it's winter...and yes, it's probable that the fluo's don't really save much in the end.

10. I *do* actually own an APC Line-R line conditioner that I use with some of my gear. It's not plugged in right now, but my experience is that it does nothing to help with airborne RFI.

11. Thanks so much for all the suggestions and comments. It's helped me get over my mind block and given me some relief to hear other's similar situations and solutions.

Re:Things I probably should have mentioned... by Anonymous Coward · 2004-12-05 06:26 · Score: 0

A single-wound inductive pickup in your guitar is inherently unbalanced. It is basically a very sensitive antenna for RFI !

To solve this, install humbuckers, or G&L "Z" pickups, or wire two single-wound pickups in a humbucking configuration.

Your F-50 Combo's reverb might also contain an internal inductive pickup. It's a mechanical spring reverb, of course... so it's either inductive or piezo; probably the former.

-The Ruggy

One more idea... by Anonymous Coward · 2004-12-06 05:41 · Score: 0

Okay one more idea comes to mind. It may be a nutty one, but should be cheap and effective:

Get a bunch of chicken wire & build yourself a Faraday cage [ie tent] to make your music in. That won't block the light, but it will block the RF, up to the multi-GHz range. Most people don't tend to notice audio interference in the GHz range.

Or conversely, wrap the light fixtures [and their offending circuits] in grounded, conductive screen mesh. Whichever is easier.

just my half [-assed] cent.

Re:One more idea... by Anonymous Coward · 2004-12-06 08:50 · Score: 0

The RFI itself may be broadband and extending into the microwave range, yet its modulation certainly includes the audio range... and the latter is what you end up hearing.

An example would be noise from a digital cell phone. The RF itself may be in the gigahertz range, but what you hear audibly in the guitar amp is a zapping sound several times per second - basically every time the transmitter keys up with another data packet.

Chicken wire would probably work though, especially if it were the finer mesh kind.

-The Ruggy

Had this problem in college by Aidtopia · 2004-12-08 05:12 · Score: 1

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 duty cycle, 60Hz in the US. You could try a tight notch filter at that rate. More of a kludge than a solution, but it might make it workable.

CF vs. Halogen by Johnboi+Waltune · 2004-12-08 06:50 · Score: 1

In the home, compact fluorescents are best for closets, patios/porches, or anywhere it's grossly inconvenient to change lightbulbs (possibly *everywhere*, if you're handicapped.) The poor light quality makes them unsuitable for any other application, IMO. I use halogen everywhere else. I'll use white LEDs when they become more affordable.

--
"The advanced societies of the future will be driven by competing systems of psychopathology." -JG Ballard

Slashdot Mirror

Reducing RFI at Home From Lighting Fixtures?

126 comments