How can I reduce outside noise inside my apartment?

Question

I would like to reduce the outside noise from inside my apartment. Outside, of my apartment is the hallway, and it can get noisy.

I was thinking about placing felt pads on my door to reduce the noise. My thinking is the sound vibrations from outside travel underneath the door and reach my room. My strategy is to place felt pads on the sides of my door, so the distance between the floor, the door ceiling and the door edges is minimal, meaning sound vibrations can't penetrate that place.

If you have other answers, lets hear them.

Answer 1

There are two types of noise in architectural acoustics: airborne and structurally transmitted. If people are screaming as they run down the hall, the screaming is mostly airborne noise and the running is mostly structurally transmitted noise.

Airborne noise can be attenuated by constructing walls, floors, ceilings, doors, etc. to absorb sound energy. Architectural components are rated by sound transmission class and in the United States, recent building codes have minimum requirements. However, airborne noise readily finds its way into a space via flanking paths.

Masking airborne noise is often a more practical strategy than trying to create a cone of silence. That is, it may seem counter-intuitive that placing a sound source in the quiet room, actually makes it more acoustically pleasant.

Structurally transmitted sound becomes more problematic particularly when the source is impact both because transmission paths are baked in to the construction and because the impacts can be irregular and at the longer travelling lower frequencies. Masking may have some effect, moving will probably have more.

Answer 2

Your options are limited being in an apartment, since you likely can't make very many permanent changes. I'll run through some ideas, though.

First, putting felt pads on the sides may help a little, but not for the reasons you think. They will do very little to dampen the vibrations -- you need mass or a dedicated damping agent for that. What the felt pads will help with is to reduce the mount of air flow through the door. Air flow is one of the absolute enemies of sound proofing. The more completely you can seal a door, the better it'll be. If you have the opportunity to attach an automatic door bottom (surface mount) and then some gaskets, then that'll go a long way towards quieting the noise.

Is your door hollow core? That is, does it sound hollow when you knock on it? If so, then you may look into replacing it with a solid core door. This can be done on a temporary basis as long as the hinges match up and you can simply pop out the old one and pop in the new one. A solid core door (especially a 1-3/4" thick one) will do a substantially better soundproofing job than a hollow core one. It does depend on you sealing it, though (see above) or else a lot of that benefit will disappear.

Beyond that... well, it really depends on how leeway you have towards making alternations to your apartment and how what your budget is. Attaching mass loaded vinyl to the walls and door would help, but would get pretty expensive very fast. Building an entirely separate interior wall would do a massive amount of help, but would absolutely cause noticeable marks when it was later removed. The flooring under the wall will certainly have to be re-done.

Answer 3

Do NOT attempt to make any modification to a common hallway door without at least consulting your local fire marshal. It is very likely that is it legally required to be fire rated, and your modifications very likely invalidate that rating. If there is a fire in your building, and investigation reveals that you modified your door, you could be held liable for damages caused by the fire.

Your fire marshal should also be able to help you determine if the current door meets fire safety requirements. If it does not, you should be able to get your landlord to install a replacement (which is likely to be significantly quieter than a non-fire rated door).

Answer 4

Several ways to approach the problem come to mind:

• Discourage noise makers: make changes to the environment so the noise makers want to leave: make the hallway temperature uncomfortable, use weird lighting, install atrocious art, provide a repellent scent, inject disagreeable noises, threatening animals, and/or arrange scary/dangerous passers-by.

• Decrease the sound reaching your apartment: sound dampening materials on the door and wall. See this answer.

• Make it harder to hear the noise: turn up your stereo, wear headphones, or install a noise generator.