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Ask Slashdot: Hacking Urban Noise?
b1tbkt writes "I live at the corner of one of the busiest intersections in my city (pop. 350k). Although I've replaced all windows, insulated, and caulked every square inch of the place, the fire trucks and cars with obnoxious stereos still regularly intrude on my home office. Most of the noise comes in through the windows. I'm considering mounting an oblong parabolic reflector in the ceiling above the windows with a steady feed of white or brownian noise directed into it (e.g., via a small speaker placed within the reflector) to create a 'wall' of sound that would act as a buffer to the outside world. Active noise cancellation would be nice, too, but that's probably more than I want to take on. I don't see any products on the market for this sort of thing. Does anyone have any experiences to share with similar homebrew noise remediation efforts?"
Have curtains made from the kind of heavy drape they use in studios. Check out how people deal with acoustic treatment in home studio builds. For instance the gearslutz.com "studio building/acoustics" subforum has many threads to geek out on.
Although there are dozens of vendors selling what sound like promising solutions, there is only one solution that really works: more mass. Think of it as a physics problem.. sound waves energy transmitted through the air that cause parts of the structure (including the structure above and below) and environment (e.g. the air around you) to vibrate at a particular resonance. The only way to stop the noise is to stop the vibration. A popular option is to use double drywall with something like rockwool insulation between the studs. You can get away with either 2 x 1/2" drywall or 2 x 5/8" drywall with a small furring strip in between without sacrificing too much living space. Look into Green Glue as an additional way to dampen vibrations in that setup. You can also go for a detached wall or "room within a room," but that starts to get expensive to do right.
If you want to look at a "serious" solution ($$$$), you should try to find a sound mitigation contractor in your area. They can survey the room during different times of day and determine what the best solution is for your situation.
How and what, exactly, have you insulated, and where is your domicile in relation to the street?
Do you have sound dampening mats on the ceiling? If not, bear in mind that most houses and apartments are above street level, and most of the sound will be reflected off the ceiling. A layer of sound dampening material there should have the largest effect.
If you live low to the ground, sound insulating the walls that can see the street, rather than just outside walls would have a similar effect.
A few strategically placed plants or sound dividers - think cubicle walls but far less intrusive - can also help.
If you must go with a noise generator (which I don't recommend), try pink noise instead of white. The sounds from the street you try to mask out are going to be mostly low frequency, and white noise will mainly add more sound energy in the higher end of the spectrum.
Although I've replaced all windows, insulated, and caulked every square inch of the place,
I've been in houses on a busy streets where the street noise stops at the walls and windows. So, possibly, you did not go far enough. For example, there are windows and there are sound-reducing windows.
Maybe you need to re-evaluate what you did to keep the noise out before you embark upon a project to reduce or mask the noise inside the room.
inside with a window that is separated from the "real" outside wall by a few inches.
You will be surprised at how effective this is while leaving the original "look and feel" of the room.
I like microcars
It will do literally nothing. Sound waves simply add. You can't get rid of sound waves by adding a bunch of random sound waves. The sound waves you don't want will pass right through. Now, if you simply have a white noise generator in your house, so that the ambient volume is higher, that may make it so that your ears have a harder time picking out specific sounds, which will, in turn, make it easier to ignore them.
Barring that, noise cancelling headphones or double-pane windows, as others have mentioned, are going to be your best bets. And double-pane windows are good for heating/cooling anyway.
As an aside, I'm also rather skeptical that noise cancellation for the entire apartment could ever be practical. The problem is the waveform bouncing off the various walls and other features of the apartment is going to be too complex to accurately measure or cancel. And then what about the sounds you do want to hear?
We put all triple-pane in our house (Winnipeg, Canada) 5 years ago. We noticed the street noise almost disappear. (Not to mention the winter heating bills dropped by ~30%+)
Cost a pretty penny, about $13K for the whole house, but man was it worth it.
Trolling is a art,
First you must measure how many decibel of attenuation you need. For this you need a sound level meter: If you don't have one at hand, a microphone + PC sound card + Audacity can be used as well (many apps for Android/Ipad are also available for this). Measure two sound spectra at your location: the first one with traffic noise present, the second one when you feel that background noise level is comfortable for you. The difference between the two spectra will tell you how much attenuation you need, and which frequencies need to be attenuated more.
Next compare the attenuation offered by each possible solutions (noise attenuationg windows, wall insulation, etc.) against the attenuation you need to achieve. If it isn't enough, move away, otherwise try installing the best solution you can afford.
Noise should be stopped before it enters the walls of your home: Once it is there, it can follow unsuspected paths to reach your ears (pipes, wall joints, etc.). The best way to stop it is to increase the acoustic impedance of external walls and windows.
Attenuation could be increased using viscoelastic materials like rubber: however they are best for attenuating high frequencies.
Triple pane really doesn't do that much for sound deadening according to the Canadian Building Digest.
Tripple panes with dissimilar glass thickness works better,
But having a different type of glass on the inside works much better.
Typically they use laminated glass for the soundproufing inner pane, with glas laminated to plastic pane which dampens transmitted vibration.
There are commercial windows available for this. These solutions seldom work where you intend to open the window to let in a breeze.
If you don't want to buy entirely new windows there are simple and less costly interior add-on panes. This preserves the ability to open the window.
Sig Battery depleted. Reverting to safe mode.