Hi, my workplace is pretty close to an elevated freeway. In the last 6 months or so, the noise seems MUCH louder than before, and it is really working my nerves.
I’m wondering if there is a computer program that will sample ambient sound, and then generate the inverse to cancel it? I’d rather not use earplugs because I like to be aware of other sounds in the environment.
Also, does someone know if this strategy works with infrasound?
Thanks!
The only way this would work is with headphones. The ambient noise is too uncorrelated to be canceled in a large space.
Come on, that’s not the only way to cancel freeway noise. You could explode a propane depot during a clumsy product transfer, causing a mass evacuation and shutting down the freeway, but getting the permits may be a little awkward.
Ahh…
The “Cancel with extreme prejudice” option.
beowulff is correct about the headphones. I can confirm that they work very well for airplane and computer noise, so they should also work well for traffic. However, there is a lower limit to the cancelling range and it won’t cover infrasound.
If you want to block as few normal sounds as possible, get an on-ear design instead of around-the-ear or earphones.
Most designs I’ve seen have internal batteries and a removable cord, so you don’t have to worry about it tangling or whatever when not listening to music.
Sunspace and beowulff: :D:D
But, don’t they have devices at airports that do that? I’m certain that the noise is all within a fairly narrow bandwidth.
**Dr. Strangelove: ** Thanks. Where would I look for something like that, and what are they called please? I assume you’re not talking about regular headphones.
Here’s a link to the CNET reviews of the best. They aren’t normal headphones, and they aren’t particularly cheap, but I’ve heard they work wonders.
Silophant’s review looks good.
I have this model. They work well, but the durability isn’t great–I’ve had to fix them with epoxy a couple of times now. I’m sure there are better models out now.
They’re generally just called “noise-cancelling headphones”, and if you search Amazon or whatever for that, you’ll find a wide variety of models, from $30 to $300. Bose is generally considered the gold standard, but Sony is also good. Not too sure about the others, besides the JVC that I have. If possible, your best bet is to try some models out at an electronics store, to see if you’re happy with the comfort levels and such.
Excellent! That is very good news; I didn’t think there’d be an affordable model. Thanks so much guys!
I am still curious about one thing though: can infrasound be cancelled out at all? (not with headphones but in any way.)
Also, here is a link to the wiki page on Active Noise Control.
This is a paragraph from that page:
*Modern active noise control is achieved through the use of a computer, which analyzes the waveform of the background aural or nonaural noise, then generates a signal reversed waveform to cancel it out by interference. This waveform has identical or directly proportional amplitude to the waveform of the original noise, but its signal is inverted. This creates the destructive interference that reduces the amplitude of the perceived noise.
The active methods (this) differ from passive noise control methods (soundproofing) in that a powered system is involved, rather than unpowered methods such as insulation, sound-absorbing ceiling tiles or muffler.
The advantages of active noise control methods compared to passive ones are that they are generally:
More effective at low frequencies.
Less bulky.
Able to block noise selectively.
Is this the technology the headphones use, or do they just cancel noise generally?
Never mind. The wiki page had a link to “noise cancelling headphones” which answered my question.
Have you asked your boss if you could get a workplace in a less noisy place?
You also don’t say why the noise has suddenly gone up. Is there someone who has opened a window?
To be honest, I don’t know. However, based on the physics, your original idea of playing an inverse sound via standalone speakers would work much better here. The problem with noise cancellation of high frequencies is that they’ll only work for a particular location, since the wavelengths are short (say, a few centimeters).
But the wavelength of 10 Hz sound (for instance) is about 34 meters, which is much bigger than an average room. So it might be very reasonable to cancel it with a giant subwoofer. There are a few details I’m not so sure about, such as how to sample the ambient sound even as you’re generating it (maybe subtract out the generated sound since you know what it is?), but I don’t see any showshoppers.
Anyway, I haven’t actually heard of such a thing, but it seems possible.
Casinos play some sort of game with noise to interfere with the ambient noise of people and games, and it drives me insane. I don’t know what it is that they are doing, but it overlays an annoying hum over everything. Makes me want to take an icepick to my ears to make it stop.
I don’t see how anybody can work in that sort of environment, let alone sit there for hours playing the slots or whatever.
I have and use the JVC noise canceling headphones to good effect. Just a guess, most of the sound transmission is probably coming through windows at your building. Are you in a separate office? If a single window, insulated drapes would be partially effective. Depending on the quality of your view, you might put up the foam insulation panels (1", 2", 4" thicknesses) found at building supply stores.
If you’re in a cubicle farm, move to where more cubical walls are between you and the windows/highway sounds. Perhaps even add some acoustic or foam tiles to your worksite to absorb any reverberation. Build a partial roof covering over your desk area (a foot or two out from the cubical edge from the side where the sound is coming from.
Further afield, perhaps a waterfall feature (actual or electronic) could produce some white noise to push the highway sound into the background.