Sound proofing a door

[Vorago]

I want to soundproof an old door in my gf's dorm.

The frame is +- 10 cm deep, they rent it so I can't drill or do any permanent mods to the house.

I was thinking of getting some closely fitted frame with 2styrofoam plates in there.

Any other suggestions?

[Smokin' Toaster]

If you have a local mattress manufacturing company, go there and see if they will sell you a sheet of the compressed shredded cotton they use. It’s purplish-gray in color with strands of various colors in it. It’s usually about 3/8” thick. It is incredibly sound absorbing. I played with a drummer with a jerk neighbor, and we lined the inside of his garage with the stuff. It was the deadest room I’d ever been in. You could clap your hands and the sound was gone almost immediately. Once, years ago I tried to use this material instead of fiberglass to insulate the enclosures of some stereo speakers and the bass virtually disappeared; the material just soaked it up.

[fu22ba55]

Originally Posted by Vorago

I was thinking of getting some closely fitted frame with 2styrofoam plates in there.

I"m not sure what absorbing material is best (the shredded cotton in the above post sounds great), but I think you're on the mark with closely fitted frames.

I played with a drummer once in his house where he had to keep the noise down for neighbors.

He had a wood frame "plug" for the door and one for the window, (both were lined with some kind of foam), and they worked great. They really deaden'd then sound outside. (I went out to listen.)

Just make sure they're a snug fit, since most of the sound reduction comes in the last couple of cm blocked.

I don't know how well this method will work for bass frequencies, though. Bass is pervasive and nearly impossible to eliminate without lots of $$$ and engineering.

[Hoover]

Shredded cotton, or acoustical foam, or fiberglass, any of those absorbative materials will do absolutely nothing to prevent sound from propogating from one side of the door to the other. Nothing.

To soundproof a door you need to completely seal the gap around the door with something massive, resiliant, and (most importantly) airtight. And then you have to ensure that the door itself doesn't resonate. It ain't cheap, and it's really hard to achieve if your goal is to not drill into the door or the frame.

[jgriffin]

The trick is to create void spaces between the sound in the room and the outer walls, which you might be able to approximate using a box of that thick insulating blue board in front of the door. Are the dorm walls otherwise pretty sound-tight?

I had moderate success using that stuff in front of windows and doors in a detached garage I used to rehearse in; it was far from perfect, but mitigated the volume enough to justify the cost of the board.

[d_whitlock]

Sound proofing a door in your GF's dorm? hee hee, sounds like something i might have done in college

[rtslinger]

Acoustic foam tile http://www.amazon.com/Acoustic-Foam-...5460466&sr=1-1 this will do the trick

[Bassmickeyd]

Isn't the door already solid core? ...... There's more of a chance you getting sound leakage thru the walls which most likely are not filled in sound insulation. ....

[Smokin' Toaster]

Originally Posted by Hoover

Shredded cotton, or acoustical foam, or fiberglass, any of those absorbative materials will do absolutely nothing to prevent sound from propogating from one side of the door to the other. Nothing.

To soundproof a door you need to completely seal the gap around the door with something massive, resiliant, and (most importantly) airtight. And then you have to ensure that the door itself doesn't resonate. It ain't cheap, and it's really hard to achieve if your goal is to not drill into the door or the frame.

Been there, done it, it worked. (Shredded cotton, that is).

If you are every wondering if someone's argument is to be believed, examine the argument for absolutes. We live in an incremental world and there are very, very few absolutes.

[topper]

There are only two things that will stop a sound wave, mass and distance.

You haven't really said what the overall problem you are trying to solve is (why do you want to sound proof the door?) but I'm guessing the neighbors are complaining about some noise leaking out.

It is highly unlikely that you'll be able to make any appreciable difference in this just dealing with the door. Though sealing it might make some small difference.

Acoustic foam will really just condition the sound you hear inside the room, not stop sound from leaving. Same for the cotton batting unless you have mass quantities of it (mass and distance).

What that stuff might do is show the neighbors you're trying and they'll cut you some slack.

What will be most effective is turning down the volume.

[Vorago]

Thanks for the suggestions so far.

I'm soundproofing the door because there's someone else in the room next to us and she's loud in everything she does. Plus, she has asthma and I wake up all the time from her coughing.

I'm not doing metal gigs in there

[Hoover]

Originally Posted by Smokin' Toaster

Been there, done it, it worked. (Shredded cotton, that is).

If you are every wondering if someone's argument is to be believed, examine the argument for absolutes. We live in an incremental world and there are very, very few absolutes.

"it worked" is an absolute; I'll bet $1,000 that it only "worked" incrementally.

[()smoke()]

physics may not be absolute, but in our world, it's about as close as it gets...hoover's post is valuable because it can save people some time and money with this issue--some of ways soundwaves behave don't always align with our preconceptions, i know i sure learned how much i'd incorrectly assumed when studying acoustics as related to the built environment

the suggestion to seal the gaps around the door is a good start

[Smokin' Toaster]

Originally Posted by Hoover

"it worked" is an absolute; I'll bet $1,000 that it only "worked" incrementally.

You are correct, it worked incrementally enough that the a$$wipe neighbor quit complaining. I owe you $1000 (incrementally). Drop by my house and I'll give you $0.01 every day till you are paid (incrementally) in full.

[ggunn]

Originally Posted by Hoover

Shredded cotton, or acoustical foam, or fiberglass, any of those absorbative materials will do absolutely nothing to prevent sound from propogating from one side of the door to the other. Nothing.

That's not quite correct. Those sorts of material work pretty well on high frequencies, but as the frequency drops, so does their effectiveness, until in the lower midrange and below, they are effectively transparent.

[Pilgrim]

If you have a suspended ceiling between rooms, messing with the door is meaningless. There's an air gap in the ceiling and nothing you can do except extending the wall all the way to the floor above will stop sound transmission.

Air gaps are responsible for most sound transmission (other than bass frequencies). Seal all the air gaps, including adding a threshold seal at the bottom of the door. That's all you can do against outside nose other than replacing the door and re-designing the room.

[Hoover]

Originally Posted by Smokin' Toaster

You are correct

quoted for emphasis

Originally Posted by ggunn

That's not quite correct.

but, but... see above!

Originally Posted by ggunn

Those sorts of material work pretty well on high frequencies, but as the frequency drops, so does their effectiveness, until in the lower midrange and below, they are effectively transparent.

Very true. However, since one rarely encounters a real-world "soundproofing"/sound transmission problem that is limited to high frequencies only, the distinction is academic from an architectural (and especially from a practical solution) point of view. OP needs to improve the STC of his door at all frequencies -- or, at the very least, at all frequencies coming from his next door neighbor's snoring, which basically means the speech band -- so reducing the high frequencies only won't solve his problem, it will only affect the spectrum of the noise that will continue to annoy him.

[()smoke()]

Originally Posted by Hoover

quoted for emphasis



but, but... see above!




Very true. However, since one rarely encounters a real-world "soundproofing"/sound transmission problem that is limited to high frequencies only, the distinction is academic from an architectural (and especially from a practical solution) point of view. OP needs to improve the STC of his door at all frequencies -- or, at the very least, at all frequencies coming from his next door neighbor's snoring, which basically means the speech band -- so reducing the high frequencies only won't solve his problem, it will only affect the spectrum of the noise that will continue to annoy him.

would shredded cotton or a chunk of mattress foam stuffed in the nose of the snorer do the trick? i can see the marketing now, and it's funny