Awful noise: reward within.

Special Interest Groups Recording Equipment
1

Hey all,

So I’m not sure if this is the best place for it, but since this is the program I used to record the sound-file, I figured you all would know a bit about audio interference. If it’s against the rules or anything, feel free to delete/lock if need be, but I’m at the point where anyone who can even point me in the right direction has earned a reward. I looked, and I can’t find any kind of definitive rule on it.

Here’s the noise: http://vocaroo.com/i/s0WQzkt4lPSu

Here’s what I know about it:

-I first heard it when I moved into my apartment about a year and a half ago, on two devices: An electric piano with built in speakers (I could hear the noise through the speakers when I didn’t have headphones plugged in, and I could hear the sound through headphones when I did have them plugged in.

-I also heard it through a couple crappy wal-mart computer speakers I had.

-The sound went away when I bought a stage piano. I cannot hear it on my stage piano.

-It’s audible even with all the power out in my apartment, via a small handheld radio through the AM station. It’s not very loud though.

-It only happens in my room: When I moved my piano out into my living room, I didn’t hear it.

-When I plugged my piano/computer in via extension cord, it still made the sound.

-I recently picked up a CAD-u37 Microphone. It’s connected to my computer via USB cord.

-When I lift, move, cover, come closer, or get further away from the microphone, the noise can get louder or quieter or change signals a bit with only a little bit of rhyme or reason.

-The same thing happens when I move the mic cord around, but not the mic itself.

-(Here’s the important bit) It’s driving me crazy.

-The apartments I live in have a cell tower antenna built on the roof. I’ve tried calling everyone I can, but they all claim there’s absolutely no way it’s their problem, since their sounds are so far above that spectrum.

I’m offering a $10 reward for anyone who can pinpoint me to exactly what the hell it is, and another 10 if someone can tell me a way to make it stop.

2

If you are a real person, have you tried High Pass Filter at 100 Hz then Noise Removal on the sound file?


Gale

3

Well I’ll say that your noise does sound like electrical interference from some digital communication system. If you could post it as a wav file we might be able to to a bit better analysis of it.

And I wouldn’t write off the cell tower as the source of the problem. Yes the signals they are broadcasting are million times higher in frequency than the noise you are hearing, but as anyone who has lived near and AM radio station or TV broadcast station will tell you: If the RF is strong enough almost anything can demodulate it.

If your new USB microphone is effected, and if you have a laptop, then you might be able to use it to track down the source of the signal.

4

Hi Gale,

I promise I’m a real person :smiley: Thank you for the idea, but the problem is I’m trying to stream on twitch. I’m worried any of my viewers will hear that on their end, and I don’t know if there’s a way to filter as I send it.

And thank you flynwill! I’ll see if there’s a way I can solve this. I do have a laptop and I’ll see if I can do it that way.

5

My cellphone charging station is right next to parts of my sound system and I can hear the phone negotiating a connection. No direct audio connection required.

Yes, I think the best you can do is draw an interference map of your apartment by walking around with a portable receiver that buzzes. Don’t use those areas.

There are ways to filter interference like that. There was a radio station in Washington, DC whose production studios and offices were in the same field as the antennas. It was a constant struggle to keep radio interference out of the sound.

Move.

Koz

6

You seemed to have answered your question in your first post - that the problem occurs in your room but not your living room.

Audacity doesn’t stream files, so you either have to filter the file before you stream it, or filter it live, which will put more strain on your computer. What application are you using to stream the file?


Gale

7

I promise I’m a real person

We administer postings before the public sees them. The ones trying to sell us male-enhancement and kitchen cabinets are easy, but sometimes someone will post a valid question that appears like it might be a hidden commercial. That’s what happened to you.

My manhood and cabinets are fine, thanks.

Koz

8

EMI from cellphones is audible on audio equipment, e.g. mics, add-on computer-speakers, see … Freesound - Search

Having said that Vocaroo | Online voice recorder sounds more like EMI from a computer …

Mystery EMI spectrogram in Audacity, (image tweaked in GIMP).gif
Mystery EMI spectrogram in Audacity, (image tweaked in GIMP).gif1280×774 488 KB