Recording studio nightmare

larryace

"Uncle Larry"
I have this problem with where my recording studio is physically located. Now I have a great setup as far as privacy is concerned. But I'm plagued with....

RF interference.

This pervades each and every electrical device that has audio or video I own. On my TV, it manifests itself as visible lines on the screen, and audible static. If I'm on a cell phone call, I hear audible static, always in the same frequency range. It sounds the same whether it is on my TV, my cell phone, my guitar amplifier, my FM radio, my studio monitors, my PA, MY RECORDINGS!

It is maddening. It comes and goes with no apparent rhyme or reason. I've heard it at 4 AM. I've tried everything, thinking the source was within my house. I ripped out my security system, eliminated every dimmer in the house, I even submerged my security electronics under water thinking some capacitor held enough charge to cause it. (this RF thing started happening not long after I had a security system installed, so I mistakenly linked them together) Nothing worked. When I did my studio, I wired it on it's own circuits, one for the lights, a different circuit for the outlets (connected to a different phase). I went so far as to turn off every other circuit in the house except for my studio. Then I unplugged everything except one guitar amp. Audible static. Unplugged the guitar amp and plugged in a bass amp. Audible static.

Finally, while driving to a nearby convenience store, I heard the static over my car radio. Always the same frequency range. That's when I realized that it was coming from a source not within my home, but nearby.

I actually filed a complaint with the FCC, and basically they said tough crap, they don't get involved in residential RF interference. Now I'll have days at a time where there is no static, then other times where for a few days in a row (like right now) it is fairly regular.

Not that I record a lot, but I'm always on edge when a recording session is planned. I don't know what else to do. If I could pinpoint the source...Does anybody have any suggestions?
 

DrumEatDrum

Platinum Member
Yes,

When I was building my studio, I read Home Recording Studio Build it Like the Pros by Rod Gervais, and in the book, he tells of once studio build he did where they had a very similar problem.

It turned out in this case, after weeks and thousands of dollars trying to solve the problem, that the building's ground wire went into the ground in two different places. So instead of the ground wire doing it's job, it was creating a completed circuit (or something like that). One snip of the 2nd ground wire, and the problem was solved.
 
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audiotech

Guest
It sounds to me like it could be amateur radio getting into everything, especially the comment you made about driving in your car. That would negate everything that is in your household. Another possibility would be amplitude modulated (AM) radio stations towers in your vicinity. Many time these can overload the front end of receivers telephones and amps. I had to do a location recording a few years back that I was plagued with RF interference. I ended up making RF filters inside a couple of XLR connectors that did the trick.

To find out where it is coming from, take an AM portable, not plugged into an AC outlet, radio and tune it to an off station area of the dial. This will act as an RF detector. when you get close to the offending source, you'll know where to look.

I definitely know RF interference can be a hassle, but most of the time it can be found and cured.

Another known source could also be high voltage areas in and around your house such as electric fences, electrical sub stations, neon signs and also CFL light bulbs. Do you happen to have an LCD television?

This is all I can really think of, but if you have any more information, I'll try to help.

Dennis
 

larryace

"Uncle Larry"
One thing I keep forgetting to do is ask my neighbors if they experience it too.
The fact that I heard it on my car radio a half mile from my house...
Yes all your grounding conductors must go to the same grounding point, If that point is connected to another grounding point, that is OK. But if you ground something separate from the building ground, that is not permitted. My house has one grounding point. The studio ground wires are connected directly to the building grounding system.

I had my studio for at least 2 years before this RF nightmare started.

I wish I knew what to do, who to call, what devices I need, l to pinpoint the source. Can a bad connection on a high voltage wire generate RF interference? I remember seeing a connection on a high voltage line in my neighbors yard glow red during a winter storm a few years back, could that do it?
 

larryace

"Uncle Larry"
Dennis, I turned off every circuit in the house, and my studio is lit with undimmed incandescents. So it's not anything in the house. I thought it might be a ham radio guy near me, but at 4 AM? It's possible I suppose. I wasn't aware of RF filters! It's only my recordings where this problem is hamstringing me, I can live with the other stuff. Pinpointing the problem is problematic, I would rather eliminate it on an as needed basis. Are you saying that an XLR RF filter is all I need? I'm assuming I need one for every mic I record simultaneously with, right?

Why did I not ask this in 2008 when I joined? If you solve this problem, I will so owe you my friend.

Where do I buy the best RF filters they make? Could you tell me exactly what to do?
 
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audiotech

Guest
Larry, I have to leave the house for a while, but when I return I'll give you more information. The best thing to try to do is isolate the source of the problem. Using the portable AM radio will help with this. The RF choke is something that I hand built inside the female XLR connector. I actually called an engineer from Neumann and he gave me the schematics over the phone. The circuitry for a balanced microphone line consists of two 680pf capacitors and two 47 - 100 micro henry inductors. If I can figure out how to send a copy of this I will. Sometimes me and computers don't see eye to eye.

I'll get back to you.
Dennis
 

Youan

Member
This might be unrelated, but there are so many radio transmissions around the world that no-one owns up to, including static or more general noise.

check out the conet project, if you'll indulge a conspiracy theory!!
 

keep it simple

Platinum Member
Hi Larry, sounds like Dennis has it nailed, but if it's still getting you down, try this http://www.lessemf.com/paint.html A friend of mine uses it in his high end studio in Amsterdam. He recons it's great, but expensive. 5L should do a good size room, but at$400, it's last resort stuff.
 
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audiotech

Guest
Larry is it possible to post what you are hearing? Do you have this only when the mic pots are open and can you make it sound better or worse when you move your microphones around? If you unplug one cable from a microphone, does this exaggerate the problem? I remember it was a short wave station in Pennsylvania that was the culprit of my problems. Sometimes they don't even have to be in the same state, but most of the time it's because of their high power and not because of their actual frequency.

Here's a copy of my hand drawn schematics for the RF filter. the components are small, they have to be to fit inside the female connector. As told to me this is not an absolute fix, but it does cure the problem in a majority of cases. As an engineer friend once said to me, "the whole world should be wired, then we wouldn't have these problems". I could imagine the long extension cable on my cell phone, lol.



Dennis
 
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mediocrefunkybeat

Guest
Surround your house with a Farraday cage!

Alternatively, listen to every word of AudioTech's advice.

If you have anything particularly critical, it might actually be worth isolating them in a Farraday Cage if the problem really is that bad. It's also a handy excuse for not answering your mobile phone once you've put it in there...
 

DaveTDC

Junior Member
This may be totally unrelated, but did you turn off all cell phones? My GSM phone causes all kinds of RF noise in my house, studio, and car.
 

larryace

"Uncle Larry"
Dennis, it has nothing to do with placement of anything. It's in the air, it globally affects any electronic device with a speaker and even my TV video screen. (Not sure if my laptop does it) If a guitar amp is on, you can hear it coming through the speakers. It's a hard to describe sound, the closest I can say is it sounds like a sort of medium pitched buzzing of varying intensity, like an insect buzzing. Yes I suppose I could post the sound of it. But it's intermittant, sometimes heavy, sometimes not, sometimes totally silent for days. So it's not like I can just put it up, it's not doing it now lol. It has no perceptible pattern, except that it's always within the same frequency range. If it comes through the speakers of a guitar amp, and I'm micing that amp and recording it, how can some inductors and capacitors make the mic not hear the static? It may work with a direct line in, like with the bass or vocals, but I mic the guitar amps. Would making a Farraday Cage for my amp work? That's Craaay-zee!

And Dave, no I didn't think of the cell phones. But we've had different cellphones in the last 3 years, and the static always sounds the same, so by virtue of deduction, I think that clears the cell phones
 

keep it simple

Platinum Member
Would making a Farraday Cage for my amp work? That's Craaay-zee!
I'm really not an expert on this, but I'm pretty sure a Faraday cage isn't a good solution for ingression of RF, but good for electrostatic shielding. Great for private dancing sessions in your dungeon, sorry, basement studio. That would certainly take your mind off the RF, lol!
 

larryace

"Uncle Larry"
I have a high voltage line in my back yard. Judging from the construction, I'd say it is in the 5,000 to 10,000 voltage range. The cross arm on the pole keeps the wires about 6 to 8 feet apart. (the wider they are spaced, the higher the voltage) I used to know a lineman, and he told me about that little tidbit. He could look at a pole and tell you around what the voltage is. About 3 years ago, during a wnter storm, I saw a red hot connection on that line, in my neighbors yard. I reported it to my utility, but I don't know what became of it.

Could that generate RF?
 

inneedofgrace

Platinum Member
I have a high voltage line in my back yard. Judging from the construction, I'd say it is in the 5,000 to 10,000 voltage range. The cross arm on the pole keeps the wires about 6 to 8 feet apart. (the wider they are spaced, the higher the voltage) I used to know a lineman, and he told me about that little tidbit. He could look at a pole and tell you around what the voltage is. About 3 years ago, during a wnter storm, I saw a red hot connection on that line, in my neighbors yard. I reported it to my utility, but I don't know what became of it.

Could that generate RF?
Not sure - I did a little research and found this article. Do you (or a close neighbor) have a wireless phone system? Could it be someone using a microwave oven, or is the interference longer than that? I just noticed you are in Bucks County. I lived in the Levittown area back in the 80's.

This article is several years old, and it is more specific to LANs, but still may be of use:

http://www.wi-fiplanet.com/tutorials/article.php/953511/Minimizing-80211-Interference-Issues.htm

Sources of RF interference that may cause problems

For 2.4 GHz wireless LANs, there are several sources of interfering signals, including microwave ovens, wireless phones, Bluetooth enabled devices, and other wireless LANs. The most damaging of these are 2.4 GHz wireless phones that people are starting to use in homes and some companies. If one of these phones is in use within the same room as an 802.11b wireless LAN, then expect poor wireless LAN performance.

Microwave ovens operating within 10 feet or so of an access point or radio-equipped user will generally just cause 802.11b performance to drop. Bluetooth enabled devices, such as laptops and PDAs, will also cause performance degradations if operating in close proximately to 802.11 stations, especially if the 802.11 station is relatively far (i.e., low signal levels) from the station that it's communicating with. The 802.11 and 802.15 standards groups, however, are working on a standard that will enable the coexistence of Bluetooth and 802.11 devices. Other wireless LANs, such as one that your neighbor may be operating, can cause interference unless you coordinate the selection of 802.11b channels.

Take action to avoid RF interference

What can be done about RF interference? Here are tips you should consider:


1.Analyze the potential for RF interference. Do this before installing the wireless LAN by performing an RF site survey using tools we've discussed in a previous article. Also, talk to people within the facility and learn about other RF devices that might be in use.

2.Prevent the interfering sources from operating. Once you know the potential sources of RF interference, you could eliminate them by simply turning them off. This is the best way to counter RF interference; however, it's not always practical. For example, you can't tell the company in the office space next to you to shut off their wireless LAN; however, you might be able to disallow the use of Bluetooth-enabled devices or microwave ovens where your 802.11 users reside.

3.Provide adequate wireless LAN coverage. One of the best remedies for 802.11b RF interference is to ensure the wireless LAN has strong signals throughout the areas where users will reside. If wireless LAN signals get too weak, then interfering signals will be more troublesome. Of course this means doing a thorough RF site survey to determine the most effective number and placement of access point.

4.Set configuration parameters properly. If you're deploying 802.11b networks, then tune access points to channels that avoid the frequencies of interfering signals. This might not always work, but it's worth a try. For 802.11 frequency hopping systems, try different hopping patterns. By the way, the newer 802.11e MAC layer, slated for availability sometime in 2002, offers some built-in RF interference avoidance algorithms.

5.Deploy the newer 802.11a wireless LANs. Most potential for RF interference today is in the 2.4 GHz band (i.e., 802.11b). If you find that other interference avoidance techniques don't work well enough, then consider deploying 802.11a networks. At least for the foreseeable future, you can avoid significant RF interference in 802.11a's 5 GHz band. You'll also receive much higher throughput; however, the limited range requires additional access points and higher costs.
 

larryace

"Uncle Larry"
INOG, Levittown is right near me, I'm in Langhorne...and coincidentally I used to live off exit 5 in Lumberton for like 14 years. You could be the closest DW member to me.
(Talking distance, you're still my girl Pol)

OK so now thats out of the way lol, the static comes in bursts, fairly loud, for 5 seconds to about 15 seconds at a clip. Sometimes there is a series of bursts back to back with a little silence in between. Sometimes it goes on for an hour at a time, sometimes it does it for 5 minutes and that's it. It sounds like an insect buzzing, only more annoying and much louder, with varying intensity. It'll start out soft then ramp up in volume then cut out for a second. Or it will start at full volume. Or I will get softer volumed stuff. No real pattern.

Like I stated earlier, the fact that I heard it a half mile from my house through my car radio really should eliminate the possibility of my neighbors wireless phone or microwave, or my laptop as the source. Unless they carry for a half mile in which case every microwave within a half mile would be stressing me..

DENNIS:

Can't I just buy those filters? I really don't feel like going all Radio Shack on it lol.
 
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