Guitar EMI RFI

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Yesman

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No Ground issue no nothing issue. Dimarzio accoustic pickup. someone/somewhere/something in my building turns on and bam high frequency buzz. I usually wait for it to be turned off but this eats up my time. sometimes it takes hours. I have Furman conditioner. but that does nothing. the EMI is in the air.

I had a 12 by 12 Inch aluminum sheet metal laying around and i put it close to the pickup and the noise went away. Now its a 1/8" thick sheet so its not some flimsy sheet by any means which i think if you are doing any EMI shielding you will need thick dense material. i dont think you can accomplish this with aluminum foil which is why those stupid guitar shielding projects are ridiculous. Very sturdy. The only problem is i have to have it really close for it to work. if i pull it away i notice it still reduces the buzz in the direction it is coming from but its much less effective. I am getting a much bigger piece of sheet metal to see if this helps cover a wider area around the guitar. in short of creating a faraday cage i am trying to keep it practical and just putting the sheet in front of the guitar where the EMI seems to be coming from where i sit to record. Pulling away from the station i record in does nothing as this noise is not coming from anything in my rig. remember EMI is air born and in the power grid so it can be coming from anything outside of my apartment. But man that metal sheet really worked i always tried thinner materials and putting it in front or something but that never worked. I never realized how thick the material really needs to be for it to block certain types of EMI. I think this is as far as i ever gotten with guitar buzz elimination. This is true EMI blocking not some power conditioner/guitar sheilding crap everyone talks about. that doesnt work. The result is great and much cleaner sound than anything else i have seen. The hum debugger works buy leaves a nasty trail effect on the recording. not my thing. I am convinced that the only way to get rid of this is through faraday cages or some variation of it.

Any thoughts ideas?
 
I don't quite get the question?

You have interference. It comes from a certain direction, moving the metal away reduces the effectiveness of the noise reduction.

This suggests you know where the interference is coming from. Swinging the guitar around produces more noise at one angle - this could be front or rear, so do the rotate test at one wall, draw the line, repeat in other places, drawing the angle - do these angles intersect, suggesting that's the direction of the source. Glue aluminium foil onto the wall, and ground it.

You suggest a question and also suggest you know what it is. Surely you need to stop the noise at source. if you can't, then screening is one solution. You say copper shielding projects are ridiculous - clearly they are not. They cured my Jazz bass which made loads of noise - and now doesn't. Aluminium foil is not as good as copper, because the thickness is thin, you cannot solder to it, and where two sheets overlap, you cannot electrically bond them together easily. Copper foil has been used as screening for over a hundred years and is electrically and physically good for the job. Sheet aluminium is an alloy of course and is not as good as copper for screening. Lead is very good, but impractical and not too healthy. Ali does screen - well enough to be useful, but it's just less good.

Have you cured the noise, or do you need help - I'm uncertain to be fair.
 
If i rotate the guitar it reduces the noise but still there. when i use the Aluminum sheet plate over it, it eliminates it completely and i dont even have to rotate it. like if they just turned off what ever was causing it. your bass probably had a grounding issue within the circuitry its self. I am talking about air born EMI. Aluminum foil does nothing compared to a 1/8" thick plate. If i'm going to stick anything on the wall its going to be 1/8inch thick not paper foil. Aluminum foil may work on the grounding issues on the instrument themselves but not air born EMI. Think about it the front of the pickup is exposed! it doesn't even make sense that it will work for air born EMI. Those guitar shielding materials work to a limited extent. if you have an air born issue near by they are not going to stop EMI from hitting the front of the pickup trust me lol. Even humbuckers would have some noise on the high end.

Just wondering if anyone had any other suggestions other than Shielding the guitars or grounding as these are not the issue here.

In the meantime I am going to try a bigger piece of aluminum sheet metal to see if that helps. Its the only thing that i have tested that actually stops an electro magnetic field from propagating
 
Does it still buzz with a wireless system? That way the guitar isn't grounded at the input.
 
Yesman said:
Its the only thing that i have tested that actually stops an electro magnetic field from propagating
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A Faraday cage?

You honestly believe someone is using a machine that makes RFI? I doubt it. This sounds like a local grounding issue.
 
You could check any fluorescent lighting fixtures and light dimmers you may have in your apartment(?). If you're lucky, one of your fixtures may be the cause and could be remedied.
 
LazerBeakShiek said:
A Faraday cage?

You honestly believe someone is using a machine that makes RFI? I doubt it. This sounds like a local grounding issue.
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you know electronics and machines and lights create EMI right? Who said anything about someone having an EMI machine? lol

I already said the guitar has no grounding issue. if it did the noise would be there all the time for the most part.
 
spantini said:
You could check any fluorescent lighting fixtures and light dimmers you may have in your apartment(?). If you're lucky, one of your fixtures may be the cause and could be remedied.
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That's one of the things i was checking. maybe i need to do a more thorough search. Or maybe a light at an adjacent apartment may be on?
 
Yesman said:
That's one of the things i was checking. maybe i need to do a more thorough search. Or maybe a light at an adjacent apartment may be on?
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A possibility. Digging deeper, it could also be a failed electronic component in a piece of older, analog gear in your place. That could take forever to track down, but is not as likely a cause as the lighting or dimmer possibilities.
 
Yesman said:
Im not using any wireless system. good old fashion multi track recording
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Just trying to solve the problem. Would you try a wireless unit? See if that stops the buzzing. It will determine what part of the circuit the issue lies.

If it is constant , then I could see the RFI idea from a light. You said it is positional with the guitar. That is most likely grounding, not air bourne whatever.
 
one other thing i should mention is that i could be in the middle of tracking with the noise and it would just go away and absolutely nothing has changed. I would literally be tracking and bam gone. I certain that it is something outside of my apartment beings switched on or off.
 
LazerBeakShiek said:
Just trying to solve the problem. Would you try a wireless unit? See if that stops the buzzing. It will determine what part of the circuit the issue lies.

If it is constant , then I could see the RFI idea from a light. You said it is positional with the guitar. That is most likely grounding, not air bourne whatever.
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i would try it just dont have a wireless system to do that.

a light source can be turned off and on its not constant. the noise is not constant it comes and goes and sometimes even with in the same recording session. It would go away while i was tracking and I didn't change not one thing while that happends. out of no where is appears and out of no where it goes away. do you get where i am going with that? meaning i do not change anything! and it comes and goes. That is not a local ground issue. I dont know if i can be any clearer.
 
spantini said:
A possibility. Digging deeper, it could also be a failed electronic component in a piece of older, analog gear in your place. That could take forever to track down, but is not as likely a cause as the lighting or dimmer possibilities.
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I checked everything short of unplugging my fridge. If it was the fridge it would do it all of the time. I dont think its in the apartment unless there is some sort of switching power supply or an electronic that is going bad. Not too sure on those.
 
LazerBeakShiek said:
What?
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LazerBeakShiek said:
What?
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You said : If it is constant , then I could see the RFI idea from a light.

That's ridiculous because a light can be turned off and on so how can it be constant? not sure you understand the idea of EMI being emitted from a light....
1. the light is on emits EMI
2. the guitar picks it up and makes a buzz
3. someone turns the light off.
4. the guitar stops buzzing.

nothing about that is constant. it can come and go much like the way the buzzing in my guitar happens. Random.


In addition, not all lights emit EMI. i think that is where you are confused. so i turned my lights off and tested this. mine are fine.
 
Oh ok. You did that test. Its not coming from the lights.

So you think it isnt even on your 10 amp service.
 
LazerBeakShiek said:
Oh ok. You did that test. Its not coming from the lights.

So you think it isnt even on your 10 amp service.
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I think it is. just some else's apartment or a some building machinery being cut on and off. Like someone turning on a florescent lamp next door or something that emits alot of EMI.. We are not limited to just our apartments breaker box. anything in the building can make its way to your breaker box and cause issues. That's why its difficult to correct.

The crazy thing is that its not even that loud. but when you start to mix and add your highs it becomes noticeable. it annoys the crap out of me. I love it when a track sounds clean.
 
Yesman said:
I checked everything short of unplugging my fridge. If it was the fridge it would do it all of the time. I dont think its in the apartment unless there is some sort of switching power supply or an electronic that is going bad. Not too sure on those.
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Don't discount the fridge too soon. Though it is always plugged in, it is not always in full operation. Most will cycle on to increase cooling, then off again.

Testing this may require leaving the doors open to shorten the time until the next cooling cycle begins.
 
spantini said:
Don't discount the fridge too soon. Though it is always plugged in, it is not always in full operation. Most will cycle on to increase cooling, then off again.

Testing this may require leaving the doors open to shorten the time until the next cooling cycle begins.
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Hmm i may just try and unplug it really quick and see if it goes away. would be faster to test. Then just plug it back in
 
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