wiring in my walls (in the key of D)
February 20, 2011 7:34 PM   Subscribe

Can anyone help me identify the sounds that my house makes?

More specifically, anytime I plug in a (digital) keyboard/drum machine or tube mic pre-amp, there is a whine and buzz that gets louder as I increase the volume. The sound can also be picked up by my metronome or hand-held digital recorder which operate on battery power and are not plugged into an oulet. The whine/buzz changes in volume depending on where I stand in relation to the drum machine/keyboard/etc. I assume my body serves as a shield of some sort?

Here is a short recording of the sounds made with a Zoom H2 recorder as I walked between a few different rooms and near some of the outlets. The electrical in this 50 year old house is dodgy at best, FWIW.

This sound is frustrating both for making recordings and for rehearsals, as you might imagine. I am mainly curious about what it is, but also whether I can reduce or eliminate it (short of rewiring the whole house). The high pitch whine is roughly a D, as is the rhythmic buzzing. Should I just be glad that it isn't a tritone?
posted by palacewalls to Technology (6 answers total) 1 user marked this as a favorite
You have a ground loop. This is a decent article that gives some ways to source it out.
posted by Cat Pie Hurts at 7:55 PM on February 20, 2011

Thanks! I just read that article and... I confess to knowing VERY little about this stuff, but the noise doesn't sound like a 50 or 60Hz hum to me... do you disagree?

Also why would a battery operated device still pick up the noise if it isn't connected to the electrical system that is suffering from a ground loop? Once again, this is all basically magic to me so I apologize if I'm being daft.
posted by palacewalls at 11:42 PM on February 20, 2011

It could be radio interference. All electrical devices create radio waves, which is why they've got FCC legal notices on the back. Way back in the old days of antenna TV and non-robotic vacuum cleaners, if you vacuumed while the TV was on, the screen would go all snowy relative to the position of the vacuum cleaner. I think that's what's going on here.

Also, try running all your power cables perpendicular to your audio cables, because that is also a thing.
posted by Sys Rq at 1:33 AM on February 21, 2011

(Also, if you've got fluorescent lights in there, that'd do it.)
posted by Sys Rq at 1:37 AM on February 21, 2011

I'm no expert but it sounds more like some sort of radio/magnetic/GSM buzz type interference that a dirty power thing to me.

Can you flip your breaker to turn off the power to most of your house to try to isolate the source? (and turn off battery powered devices as well) If you have lots of close neighbors it might be tough to figure out the source.

Here is a maclife article about using ferrite beads to stop the buzz, sounds like it's worth a try.
posted by yeahyeahyeahwhoo at 5:50 AM on February 21, 2011

Not 60Hz noise, not a ground loop. Sounds like RFI noise. It can come from a switching DC power supply that either (a) sucks or (b) is breaking, can come from a cell phone that's going nuts, from a PC power supply... one of my MacBook Pro power cubes is currently making that same sound audibly, which is a little scary (it's on its way to the grave).

Your options are to add shielding to your susceptible electronics (tinfoil hat time, for real) or to use those same devices as "probes" and go hunt for whatever's broadcasting to your house. It's probably close, like within a room or two. As soon as you unplug the offending device, the buzz will go away.

(Systematic debugging step 1 would be harsh but effective: Throw the main breaker for your house and use the battery-powered recorder; the sound should be gone. If it's not you may be haunted, or possibly live directly underneath an FM broadcast tower.)
posted by range at 7:52 AM on February 21, 2011

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