Sound insulation of an interior door: a thick curtain?

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Kcenia
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Sound insulation of an interior door: a thick curtain?




by Kcenia » 30/08/11, 10:39

Hello
It's all in the title actually
the rooms of the house are in a row, they overlook the other rooms and especially the living room without any other door or thing to close apart from that of the room itself which must be 2 cm to break everything.
Question noise, it's simple, we hear everything that happens at the other end of the house.
I was wondering if putting a thick curtain could help significantly reduce noise? Is there another easily retractable and preferably ecological solution?
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dedeleco
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by dedeleco » 30/08/11, 11:28

Sounds in the air are strongly stopped by repeated layers of very heavy light, with the greatest difference in density and speed of sound possible.
The thickness of the layers is less important than the number of breaks in the speed of sound, which lead to reflections that stop sounds.
An example of double glazing or even triple without leakage strongly blocks outside sounds compared to a single glazing.
Pay attention to the floor and ceiling and how the room is furnished.
If the surface of the walls is covered with heavy bump structures, the sounds will be diffracted and stopped.
Light floors transmit sound too.
So also heavy on the ground on light cork and carpet attenuates the sounds
A heavy lead curtain, or heavy partition (solid cement, brick) then air, then re-heavy, will attenuate the sounds.
So the density is important and not only the curtain which has a fairly low density.
It is also necessary that few of the surfaces are without this sound cutoff.

Your house is in what, floor, walls, doors, which must be light and how thick.
You must add layers of heavy, light, even 1cm.


In detail to be observed with care while respecting the principle of soft heavy layers repeated without leaks:
http://msdrums.chez.com/insonorisation.htm
http://fr.wikipedia.org/wiki/Isolation_phonique
http://forums.futura-sciences.com/habit ... ppart.html

examples of materials:
http://fr.soniflex.com/?gclid=CI6bvrDY9 ... 3wodbA0rAA
http://www.solutions-elastomeres.com/Ch ... 3wod63wsAA
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Sound insulation: materials




by Obamot » 30/08/11, 11:42

All this is governed by the "Law of mass" (Berger's law, EPFL course):

"The sound insulation offered by a building element increases by 6 dB for each doubling of its surface mass."


So it's not "thickness", Nor the alternation of "heavy, light" but good "intrinsic weight"Of the material, which makes thermal insulation. What makes Dedelco say that, are the acoustic correction "sandwiches" (+ hard insulation) that you see in recording studios, but the possible light materials used, are only there to CORRECT the acoustics.

Thus the presence of "air" between two heavy partitions - or the use of thick curtains - only insulates up to ... their surface mass (ie peanut).

Image

The proof: according to Lauber (3), in the case of wood fiber (cellulose wadding or textile fibers), the insulation coefficient is hardly higher than the "background noise" of a room (room type. library).

The usual confusion comes from the fact that we confuse the "Phonic correctors" with them "Phonic insulators".

An experiment very simple to carry out, is to open a large window, then to place the fabric to be used as curtain in front of the window, and to check if one always hears the sounds coming from outside ... In general, enough to convince ...
IMHO: NEVER confuse thecoefs of reflection and absorption sounds with the sound insulation coefs.

And to finish, as in the building nothing is simple, it is necessary to add the phenomena of propagation of sounds through materials. There it gets complicated!

So the curtains, will correct the acoustics of the room as well as possible, which will become more muffled ... At best they will dampen the sounds produced in said room (but let's be clear, in this case: it is not insulation!). But the curtains will not prevent the propagation of sounds from other rooms. So, unless you make an auditorium for an audiophile stereo system, the expense is relatively unnecessary.
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by elephant » 30/08/11, 12:58

Of course, I have a client who has already called me into his office - he gravitates in the high spheres of Electrabel - 7 cm doors with seal.

Other than that I saw other doors in private homes, recording studios and especially medical offices.

1st rule: sealing.

I could see that a single double glazing frame that is not firmly applied at the joint makes a significant difference.
Do not delude yourself with old interior doors unless you change the lock for a 3 or 5 point system if possible.

the most frequently used solution is felt: 4 or 5 cm on the internal panels of thickness which they generally cover with a studded skai "to make chic"

This is usually enough to make ordinary conversations difficult to understand. For the bass: heavy walls and floating slab.
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by Kcenia » 30/08/11, 13:20

So basically, I forget the curtain, I put a seal so that the door closes a little better than at present and if I ever want one day to really hear too much what is happening on the other side , I steal the door from the doctor : Mrgreen:

thank you for your explanations :)
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by dedeleco » 30/08/11, 13:30

This sentence forgets a good part of the propagation of sounds:
Thus the presence of "air" between two heavy partitions - or the use of thick curtains - only insulates up to ... their surface mass (ie peanut).

because it forgets the passage of sounds between very different environments and we must read the basics of sound propagation on:
http://fr.wikipedia.org/wiki/Imp%C3%A9dance_acoustique
the sounds passing between two very different environments in acoustic impedance are very strongly reflected and therefore do not penetrate by staying outside:

The characteristic impedance is a property of the material considered and is equal, in the case of an unlimited space, to the product of the density of the material ρ by the speed of sound c in this same material:
Z = density. vs.


The energy transmission coefficient expresses the quantity of energy contained in the transmitted wave f2, given a direct incident wave f1:

T = 4 Z_1 x Z_2 / (Z_1 + Z_2) ^ 2}

If we consider the interface between water, acoustic impedance Z1 = 1,5 · 106 Pa.s / m, and air, acoustic impedance Z2 = 430 Pa.s / m, we find coefficients reflection and transmission:
R = -0.005dB
and T = -30 dB.


Sounds are hardly transmitted from one environment to another, as can be seen in scuba diving.


This phenomenon exists in optics and is used to make filters, but in acoustics the variations of impedance can be enormous contrary to the usual optics (if not usual, we obtain the same by almost stopping the light !!)

These coefficients are analogous to those given by Fresnel formulas in electromagnetism.


So I repeat: alternating sandwich layers, heavy rigid (high speed of sound and high density) light and soft, almost reflect sounds and isolate very well by transmitting very little !! !!

Example: you take double-glazed single-pane glass and transform it into double glazing with air space between two single-thickness glasses (same mass), and you notice the much better sound insulation, which I see in my homes at my house without stopping between single glazing and double glazing !!!!!

So heavy hard alternating layers on light soft ones are very effective and widely used everywhere to insulate by preventing sounds from penetrating through a wall, a door or a window.

measurement with:
http://fr.wikipedia.org/wiki/Tube_de_Kundt


In fact, physically, it's the same as trying to move a heavy car with soft rubber, which won't make it move !!
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Re: Sound insulation: materials




by Leo Maximus » 30/08/11, 13:37

Obamot wrote:All this is governed by the "Law of mass" (Berger's law, EPFL course):

Absolutely, Obamot, it's the Law of Mass. What phonically isolates is the lead wall (!) Or the concrete wall, not the fabric.

In acoustics, sound insulation is almost always confused with architectural acoustics. The famous "egg carton" is useless in sound insulation, on the other hand, it plays in architectural acoustics by modifying the reverberation time.

But we will continue to put light materials for sound insulation, that's how it is.

Architectural acoustics is a very little known science.
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by dedeleco » 30/08/11, 15:49

I repeat basic physics it is the product density (or mass) by speed of sound that counts (air 330m / s) not only the heaviness, and therefore the heavy but soft lead (than 1200m / s) is less good than iron or steel (5600m / s), lighter but more rigid with higher speed of sound and therefore the iron or steel plates alternated with light soft (air) are much more effective than lead by making the density product by speed of sound in steel !!
see the speeds of sound:
http://fr.wikipedia.org/wiki/Vitesse_du_son
The glass is good with 5300m / s and an intermediate density, as shown by the double glazing and triple, so airtight.
which stop the sounds much more than the same amount of glass in single glazing (and triple thickness) !!

So the most effective is:
well sealed, because cracks and air leaks let the sound through well
et especially walls of a few mm, alternating impedance alternating high then low then high, like iron, steel, or glass, then cork, air or felt, then again iron, or glass, several times on walls and doors are enormously very effective compared to a simple heavy coat recommended by others which do not give the exact sound propagation references, which everyone can check !!! (and not just architect's recipes, without any precise verifiable physical demonstration)
Light soundproof doors use this method, alternating layers, high impedance then low impedance, even wood, air, rigid wood.
Speed ​​of sound to calculate this impedance:
http://fr.wikipedia.org/wiki/Vitesse_du_son
http://fr.wikiversity.org/wiki/Introduc ... acoustique

Read these exact explanations from an ultrasound specialist who constantly checks this by doing ultrasounds:
http://imrt1.lgm.free.fr/physique/acous ... n_sons.pdf
http://imrt1.lgm.free.fr/physique/acous ... x_sons.pdf
http://fr.wikiversity.org/wiki/Introduc ... acoustique


The steel or glass plates must be thick enough (a few mm) to be rigid, well fixed, so as not to vibrate like a too thin membrane (if around 0,1mm thick).

If your walls of wall are usual in bricks of 5 plastered, it is especially your too light doors which let pass the sounds, and caulk them more and double them with rigid plates iron or glass or other dense martial materials at speed of fast sound, in alternating layers of about mm with soft, air, cork, will solve the problem, better than making the door ultra heavy with a single thick layer of lead.
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by Obamot » 30/08/11, 16:24

Yes and there are severe cases Maximus Leo: chessy: And those who make their butter with ...

(The) 1st rule: sealing.

I could see that a single double glazing frame that is not firmly applied at the joint makes a significant difference.
Do not delude yourself with old interior doors unless you change the lock for a 3 or 5 point system if possible.


Bein an “insulation” it is indeed a form of sealing! In this case => law of mass => we are OBLIGED to take heavy.

For the spread, I haven't touched
(since I only responded to the use of curtains ...)
Because if we add the resonance phenomena we can even bring down bridges. So let's stop the HS ...

So I would stop there, because the seals, the use of frequency absorbing materials and alternating them, it's a matter of course, but:

But the basic rule to understand is the weight.

No insulation with only absorbent / corrective materials. Bar point.
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by Leo Maximus » 30/08/11, 17:51

The law of mass also applies to joints. When there are no joints, we can consider that the joints exist but they have the density of air ... : Cheesy:

The bp encountered by Kcenia may come from the presence of a reinforced concrete slab, isolated from the ground in addition. It transmits noise very well from one room to another through the slab first and through the partitions afterwards. There is not much to do there.

In the past, houses were built with cupboards 1 m deep which served as partitions between the rooms. It was very effective for sound insulation.
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