Help Identify this Noise? (example audio included!)

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Russell Vesely

Freshman
Aug 17, 2013
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[TD="class: alt1"] We've been having a strange noise issue in the studio, and can't seem to suss it. We've eliminated every piece of gear as a source, we've had the power company come out and meter the lines with various gadgets, we've tried EMF filters, and the power company even brought out a cherry-picker bucket truck to check the transformer, but they say everything checks out. Here is a link to the sound in question; if anyone has any suggestions as to what the hell it could be, PLEASE let us know! It's showing up in the recordings, and that's not cool. (The example of the noise was run through a noise filter and boosted 42dB total with a limiter to remove background 60-cycle hum and to make the offending noise more audible, respectively.)

Could it be RF interference? Cell tower? It's localized, and doesn't happen with surrounding buildings. It also seems to have something akin to a pattern, of sorts. And there also seems to be some sort of structure to the waveform shape, though what it might indicate is beyond my scope of understanding.

https://soundcloud.com/thaddeus-moor...-is-this-noise

Thanks for any and every suggestion you might have!

Thanks a lot for any and every suggestion!
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Re: Help Identify this Noise? (example audio included!)

What have you done to evaluate the power coming out of the wall? Have you 'scoped it? Have you looked for any odd harmonic distortion?
 
Re: Help Identify this Noise? (example audio included!)

The power company had plugged some gadgets (not sure which, as I was tending to other business at the time) in the outlets and checked it all out; they tested the transformer on top of the "phone pole" outside, a company called EMF Power Pro ( EMF Power Pro LLC) came out to test the lines with their own testers... A "Silly scope" wouldn't be a bad thing to get hold of...
The owner seems to think the waveform looks like "data packets," for whatever that's worth...
 
Re: Help Identify this Noise? (example audio included!)

Russell Vesely said:
The power company had plugged some gadgets (not sure which, as I was tending to other business at the time) in the outlets and checked it all out; they tested the transformer on top of the "phone pole" outside, a company called EMF Power Pro ( EMF Power Pro LLC) came out to test the lines with their own testers... A "Silly scope" wouldn't be a bad thing to get hold of...
The owner seems to think the waveform looks like "data packets," for whatever that's worth...
Click to expand...


Stop guessing and get your power 'scoped and fully analyzed. If the noise is coming in with the AC as the carrier, you need to either "firewall" your power with a top-quality on-line UPS or disconnect everything in the neighborhood.

I'd get the on-line UPS anyhow if you're running a production studio.

Edit:

I just looked at the link to the EMF outfit.

You've GOT to be kidding!!!

FYI, for travel expenses, 3 weeks paid suite in a hotel and a "reasonable" fee, I'll come exorcise your power demons and cleanse your building of karmic backup.
 
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Re: Help Identify this Noise? (example audio included!)

I'd consider bypassing utility power and bringing in a generator to see if it's utility power or some external EMF/RFI infiltrating your building.
 
Re: Help Identify this Noise? (example audio included!)

Noise on line or neutral won't get past the power supply on a properly functioning piece of equipment (gear with nasty hum may be a different story). Noise on the ground conductor is a different story, although the impact of any such noise will depend on what is being done with the protective earth conductor within your equipment.

Yo say you've eliminated every piece of gear as a source. How? By checking each one individually for the noise?

What do your equipment interconnects and grounding look like? That you needed to filter out 60 cycle noise in your sample suggests that you may have some grounding/shielding problems, and this noise could be coupling in as part of those issues.
 
Re: Help Identify this Noise? (example audio included!)

Dick Rees said:
Edit:

I just looked at the link to the EMF outfit.

You've GOT to be kidding!!!

FYI, for travel expenses, 3 weeks paid suite in a hotel and a "reasonable" fee, I'll come exorcise your power demons and cleanse your building of karmic backup.
Click to expand...

Anybody that is using the term EMF to refer to anything other than a generated voltage is a snake-oil salesman.
 
Re: Help Identify this Noise? (example audio included!)

My guess is something in the air, not the wiring.
Have you tried balanced power? That would cure it, if it is in the wiring.
 
Re: Help Identify this Noise? (example audio included!)

You don't happen to have an airfield near you? I've heard similar noises from the ground radar from my neighbouring airfield get picked up by TVs and the like.G
 
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