Are you wondering what is happening on the other side of the wall? Are you interested in listening to it? It doesn't matter if it's a stranger or close person Whether it's in your house or somewhere else, it's not very noble to spy on another person anyway. If you still decide to eavesdrop, then there are several ways to hear everything that happens clearly and clearly. Be aware of all the risks and criminal liability before committing such an act.

Steps

With a glass

Take a glass. So, you still decided to go for it. How to start spying? by the most the easy way will attach the glass to the wall. An "acoustic bond" is created between the wall and the glass, which allows sound waves to travel from one side of the glass to the other. A soda or beer glass is best. Some spies claim that cardboard cups are excellent for this purpose, but glass is much better than other materials at conducting the vibration of sound waves.

Explore different parts of the wall in search of the best point. In some places on the wall, the sound will be transmitted better. This is due to the uneven structure of the wall or due to different distances from the sound source. Check the sound quality in different points until you find the best place. This can sometimes be difficult, especially if you need to eavesdrop through the ceiling. If you are too far from the wall, the sound will not be heard clearly enough.

Lean the edge of the glass against the wall. Remember that in order to achieve an acoustic effect, you need to put the glass against the wall. Do this by placing the glass flat with the rim against the wall. Now acoustic waves travel from the wall to the glass, in the process of which the sound is amplified.

• With the glass against the wall, rest your ear against the bottom of the glass. Move the glass along the wall if the conversation is not well heard.

With Hole

1. Make a small hole in the wall with a drill. Such a variant of eavesdropping through walls using a hole and a plastic membrane was discovered by scientists in South Korea and Japan. First, drill a small through hole in the wall. Long and thin drill fit better Total.

   • Don't expect to hear too much through just one small hole. In fact, a single hole seriously interferes with sound transmission.
   • Try to drill a hole while your neighbor is also working with a drill. Otherwise, he may notice the debris from the drilling and hear the noise.

2. Close the hole with a thin membrane. So you dramatically improve audibility. Studies show that by closing the hole with a thin membrane, the sound transmission improves so much that there is no wall at all, because the membrane equalizes the pressure on both sides of the hole through which the sound passes.

   Eavesdrop. Once you've got the hole covered plastic wrap start listening! At correct execution of our instructions, you will clearly hear everything that happens behind the wall.

   • For the best effect, you can combine this method with the first. Place a beaker over the membrane hole.
   • remember, that this method has its drawbacks. Your neighbor may hear a sound, notice a hole in the wall or the debris left behind after drilling, and become suspicious. Do everything very carefully!

With a spy stethoscope

1. Prepare the necessary ingredients. Now we will use more specific spy equipment. You can make a stethoscope at home or buy one. Ready product will save you time, but you will have to spend several hundred dollars. A homemade stethoscope will cost you less than $25, but that's assuming you have a good MP3 player.

   Disassemble the microphone. You will need to open the microphone case to get to the wire, then remove the cover and get the microphones themselves. Then insert the removed microphones into the earpieces of the stethoscope.

   • The most suitable tool for this is a clerical knife. They can make an even cut that will allow you to get to the contents. You should have 2 microphones and a 3.5 mm plug (cable).

2. Disassemble and reassemble the earpieces of the stethoscope. Remove the earphones from the stethoscope. It's easy enough. They should come off with little effort. Don't throw away the headphones as you will need to install the microphones in them.

3. Attach the stethoscope to your MP3 player. Finally, attach the stethoscope and microphones to the MP3 player. Sound coming from behind the wall will be amplified by microphones, transferred to an MP3 player and recorded.

   • Connect the resulting stereo cable to your MP3 player. Your spy stethoscope is ready.

Whether any waveform can pass through an object depends on how much that wave is reflected, scattered, or absorbed.

Sound waves are of course reflected by the wall, otherwise you wouldn't hear that echo from it, but not all sound is reflected so some travel into the wall. Whether the sound is scattered and/or absorbed by the wall depends on what the wall is made of. Remember that sound is a mechanical vibration. The sound hitting the wall causes the wall to vibrate, and the other side of the wall causes the air on the other side to vibrate. A good solid wall won't dissipate vibrations too much, so you'll get some sound through it. A wall filled with, for example, fiber optic insulation will absorb sound much more, so it will transmit less normal.

The light is also reflected by the wall, otherwise you wouldn't be able to see it. How much light is reflected depends on the wall: a white wall will reflect more light than a black one. However, the dominant interaction with the wall is likely to dissipate. If the wall were made of glass then obviously light would pass through it. The concrete wall is made from miniature grains of calcium carbonate and aluminosilicates, and while these materials are obvious to visible light, reflections from all those grain boundaries scatter light strongly. If a particular wall were very thin, like 0.1mm, then you would still get some light transmission through it.

Response to Zeynel's comment:

Consider a microphone. Sound waves are made of back and forth vibrations of air molecules, and if you are sitting at a fixed point in space they are back and forth, the vibrations create fluctuating changes in pressure. The microphone works because when the pressure is high, the sensor in the microphone pushes back, and when the pressure is low, it pulls it forward. The end result is to make the pickup in the microphone oscillate in time with the wave, and in the microphone this movement is used to create an oscillating electric field.

The microphone is designed to be very sensitive to changes in air pressure, and the wall is not. However, even a solid wall is resilient in the sense that it distorts when you rush it. Thus, the wall will also move in response to the fluctuating pressure created by the sound wave. It will move much, much less than the microphone sensor, but it will move. If the side of the wall facing the sound wave oscillates then obviously the wall will oscillate as well. This behaves like a loudspeaker, i.e. the opposite of a microphone, as the oscillating surface of the wall creates an oscillating pressure in the air next to it, and this creates a sound wave. This is how sound travels through a wall.

Re your last comment, "if we said some sound waves pass through the wall": you need to remember that a sound wave is not a thing. It's just the movement of something else. In air, a sound wave is the movement of atoms in the air, and in a wall, a sound wave is the movement of atoms in a wall. It's true to say that a sound wave travels through a wall, but it's a vibration that doesn't move anything through the wall that you could point to. In this respect, sound is completely different from light, where in principle you could follow a photon as it travels between different media.

One important function of walls and ceilings is to block out sounds.. This is achieved in several ways. Soundproofing a room can be as simple as filling up the cracks around a door; however, it may require rebuilding the entire wall or lowering the ceiling. Noise not only propagates through the air, but also easily penetrates through solids (through walls, pillars and ceiling beams). Sound can also bend around corners and pass through very small cracks.

In order to create an effective sound barrier, the path that sound travels through solids must be interrupted. Sound is the pulsating movement of air molecules through the eardrum. When a vibrating surface (such as a speaker diaphragm or vocal cords human) disturbs the air in the room, it forms a wave-like movement of molecules. Colliding with each other, the displaced air molecules transmit acoustic energy (to some extent, in the same way that jelly transmits vibration) until this movement reaches the eardrums.

Any barrier that interferes with this movement attenuates the sound; the denser the barrier, the less sound passes through it. Brick wall 100 mm thick significantly better sound barrier than wooden frame partition 100x50 mm. Unfortunately, a solid wall that is thick enough to attenuate sound to a great extent would be too heavy for a load-bearing floor.

An increase in the density of ordinary wood will not be of great help. frame wall by additional layers of drywall or by placing insulating material between the uprights - two common approaches to soundproofing. Often the drywall will continue to pick up sound vibrations and transmit them through the solid studs, driving the same flexible drywall on the other side of the partition.

Acoustic tiles behave similarly - very effective in absorbing sound within a room, they hardly interfere with the transmission of sound from one room to another, since sound waves pass directly through their light porous structure.

Two more factors complicate the issue of soundproofing. The first of these, called lateral transmission, often occurs when neighboring houses are connected by a common wall. Although the noise may be partially blocked by the wall, the sound continues to travel through detours (through open windows, for example) or be transmitted in the form of vibrations through floors and ceilings. b

The second factor to keep in mind is the frequency of the sound to be blocked.. Ensuring soundproofing at the edges of the spectrum is a very difficult task.

Trying to make a home soundproof must begin by identifying obvious deficiencies in its protection. Repair the common wall and restore any damaged connections. Extend the plaster closer to the floor if it is at the level of the baseboards. Fill gaps around ends beams lying at the base of the wall, mortar. Cover with acoustic seals or acrylic putty the places through which pipes enter the room, electrical cables or other lines of communication. Cover doors and windows with draft protection, replace lightweight hollow doors with solid ones, and single pane window panels with at least two pane panes. All of these measures can lead to significant improvements at relatively low cost, and you will only have to keep looking for more substantial options for soundproofing the wall if you have not been able to reduce the noise to the desired level.

To reduce the passage of sound through a dense structure, it is necessary either to increase the mass of this structure, or to place a "shock absorber" between the receiving and transmitting surfaces. If there are posts in the wall, best solution will isolate the surface of the wall from the lattice itself with the help of elastic pads. Attached to the studs, these lightweight metal strips are flexible enough to absorb and dissipate vibrations on the wall surface (much like a spring dampens mechanical vibrations).

To further enhance the sound dampening effect of the resilient pads, install fiberglass insulation between the posts.

If the wall is masonry, a false wall grate installed 30 mm from the corresponding wall and attached to the floor and ceiling will serve the same purpose. To make a false wall, use metal studs, which are lighter, more resilient, and require less space than wood studs. You can block out sound even more if you fill the space between the grille and the existing wall with fiberglass insulation material.

The same sound control principles apply to homes. new building with the advantage that they can be applied from the very beginning of construction. A wall in which 150x50 mm studs are stepped (such a wall has two separate rows of studs placed on 150x50 mm slabs) blocks the propagation of sound between the two rooms so effectively that it makes loud speech barely audible.

Through a double (100x50 mm) with two completely separate gratings, even a scream is barely audible. In addition, such a wall well reduces low-frequency sound vibrations.

ceilings largely meet the same sound attenuating properties with one exception. Noise from blows like knocking high heels coming from the ceiling presents particular problems. Elastic pads on ceiling beams partially eliminate such vertical sounds, but, as a rule, you have to put a thick carpet on felt, sponge rubber or cork flooring in places where you walk.

The basic tools and supplies you'll need to make these soundproofing projects a reality, from putting up a double wall to caulking holes, are available from hardware stores, acoustic materials in some areas you need to order. Since screws are better suited for installing elastic gaskets, it usually pays off if you rent an electric screwdriver or buy a set to drive screws for a multi-speed electric drill.

Porous Acoustic Tiles Ceiling coverings reduce room noise by absorbing airborne sounds that are transmitted through partitions to adjacent rooms. Plasterboard ceiling with resilient pads and the insulation between the beams does not muffle, but greatly reduces the sound transmitted to the upper room.

The sound-stopping properties of these five timber-framed walls are determined by a combination of factors: the overall thickness of the wall, the density and hardness of the coating material, the width of the cavity between the coating and the support, as well as the contact between them.

If a standard (100x50mm) stud wall (left figure) is covered with a single layer of 12.5mm drywall, normal speech in the next room is unintelligible. If you add a second layer of drywall, loud speech is heard but not understood.

The best result can be obtained with one layer of drywall if added to one wall elastic pads and insert between posts insulating layer thickness from 50 to 100 mm. Even better would be a new wall covering insulated from the old one.(fig. in the center). In new structures, structural and airborne sounds can be blocked by separating and staggering opposing (100x50mm) studs on rails (150x50mm) and applying an extra layer of drywall to one side.

Still more effective double wall- 100x50 mm. Consisting of two pairs of upper and lower straps, installed at a distance of 150 mm from one another plus 150 mm of insulation between the joints, such a wall attenuates sound better than a 100mm solid brick wall.

Installation of soundproof strips.

To seal gaps on the sides and top of the door, attach a rigid air barrier strip with a flexible seal or self-adhesive strip to the jambs and to the top rail, making sure the sealing tape is firmly pressed against closed door. To seal the gap under the lower edge of the door, install a threshold gasket between the jambs; the gasket shown here (fig. inset) contains a solid aluminum body with an elastic insert that compresses when the door is closed. The bottom edge of the door is slightly beveled for a better fit.

Repair non-closing or ill-fitting doors before installing soundproof tapes. Keyholes and mailboxes have special soundproof seals.

How to soundproof a wall with studs

Remove drywall to expose underlying studs, fill gaps between studs with 50-100mm fiberglass insulation mat. On the outer wall the steam-resistant base of the mat should be located facing the room, on outer wall no vapor barrier needed.

Starting as close to the ceiling as possible, attach the elastic channels to the posts, and at the very top the connecting flange, using 60 mm galvanized nails for drywall or 36 mm screws for drywall walls. Continue fastening spacers at 400 mm intervals; the bottom pads must be no more than 150 mm above the floor. If the spacers connecting the lengths are fastened to a long wall, overlap their ends by 50 mm (fig. inset) and place the joint on a post.

Trim the drywall panels to be about 50mm shorter than the height of the wall and attach them vertically to the resilient spacers using 22mm drywall self-tapping screws spaced at 230mm intervals. Use the foot lever to support each panel as you install it.

For additional soundproofing, attach the second vertical layer of drywall with 36mm self-tapping screws, positioning the joints so that they do not line up with the joints on the first layer.

Cover the joints between the panels with tape and filler, apply acoustic sealant around the entire perimeter of the wall (fig. inset).

Free-standing sound-damping wall

This metal stud wall is mounted on a floor track 30mm from real wall. The space between two walls and the inherent metal racks elasticity is created on the way of sound passing through the structural elements, a double barrier.

In addition, to reduce airborne sound, the space between the uprights is filled with a 25mm fiberglass insulation mat. Before installing drywall, the edges of the grille are covered on all sides with acoustic sealant.

Adding an extra layer to the ceiling

Determine and mark the location of the beams, in the case of a MARCO prefabricated monolithic floor, follow the step floor beams to attach to them. Attach the first two rows of spacers at right angles to the beams at opposite ends of the room through the fastening flanges to the beams.

Use self-tapping screws No. 38. Divide the lying space into equal intervals for other rows 500-600 mm apart and taking into account the location of the floor beams. Mark the position of each row by hanging a beacon line on the beams.

Attach the remaining spacers to the ceiling, making sure all flanges are facing in the same direction.

If you are joining gasket sections, overlap the ends and attach them to the beam through both flanges.

Strengthening drywall and insulation

After all resilient pads are in place, place the first row of drywall panels on them and insert 50mm fiberglass insulation boards between the drywall and ceiling. If more than one drywall sheet is required to cover the entire ceiling, position the joint between the two sheets through a channel (fig. inset).

With the first row of drywall in place, install the remaining rows, one row at a time, filling the space between the drywall and the ceiling with insulating board. Seal the edges of the ceiling with acoustic sealant and finish the joints on the drywall.

Ceiling soundproofing restoration

Remove the ceiling, taking the same precautions as when removing damaged plaster, and install between the exposed beams pieces of fiberglass insulation mat with a thickness of about 100 mm, vapor barrier down. Attach the vapor barrier to the beams with staples.

Install elastic pads on the beams and fasten drywall sheets at right angles to the pads, as shown above for fixing soundproofing to the ceiling.

Using Silencing Racks

Hang two beacon lines on the ceiling at a distance of 140 mm from one another for top harness(150x50 mm). Lower the plumb line from several points, make a mark on the floor and draw a guideline for the bottom harness.

Soundproofing walls in the apartment. Do's and Don'ts

Modern apartments far from ideal. How many times have you heard complaints about a noisy neighbor, a teenage pianist, and loud music at 2am? All this can be solved, especially if you have just started repairs. Soundproofing is an excellent solution for construction. A wide range of materials will allow you to choose the most suitable option for your home, and professionals in their field - to perform high-quality soundproofing work.

How not to do

In the modern market of construction and finishing materials exists today huge selection materials with excellent soundproofing values ​​and characteristics.

Very often, the buyer in his choice is based on such parameters of the material positioned as a soundproofing material. But he does not take into account one very important circumstance. The values ​​indicated by the manufacturer show only the soundproofing characteristics of the material itself. And these parameters can manifest themselves only under the condition correct application such material. The manufacturer cannot and should not take into account the peculiarity of the sound wave to create vibration. This can and should be done by a specialist, at least at the level school education familiar with the physics of sound.

Alas, in our practice we often encounter the opposite. The most common mistake when soundproofing walls in an apartment is to tightly bind the soundproofing material to the insulated wall. Beware of sticking and plastic doweling of Styrofoam or Extruded Styrofoam to the insulated wall. This is the most common wrong way to soundproof walls. Your neighbor will thank you. He will absolutely not hear you. You will hear it twice as loud.

Do not allow the drywall construction to be rigidly attached to the insulated wall using conventional dowel nails/self-tapping screws. Get the opposite effect.

These common errors are due to elementary ignorance of the properties of a sound wave. A sound wave passing through a solid barrier (in this case, through a wall adjacent to its neighbor) generates a transverse wave, which causes bending vibrations of the barrier. The sound just loosens the wall. And the thinner and less dense the wall, the more it loosens. These vibrations create their own sound wave that copies the source acting on it. The thicker and more massive the wall, the greater its inertia, the weaker it will transmit sound. Lightweight soundproofing material rigidly bonded to the main wall does not have sufficient mass to resist the bending vibrations caused by the sound wave. Soundproofing performed in this way will not resist, but only facilitate the passage of a sound wave, increasing the amplitude of bending vibrations.

How to do

How does sound get into an apartment?

1. By air

Sound can pass through walls where it encounters minimal resistance: through cracks in the wall, at the junctions of wall and ceiling, wall and floor, wall and adjoining wall, through ventilation shafts, installation boxes for sockets and switches, through plastic window slopes, hollow window sills through the windows themselves.

To get rid of the penetration of sound by air is the easiest and most inexpensive option for soundproofing the walls of an apartment. It is enough just to plaster the walls. If there are gaps, fill them with plaster to the maximum possible depth. Do not fill them with mounting foam. Before applying the plaster, it is necessary to carefully seal all joints along the perimeter of the walls with plaster or mineral wool. Make sure your installation boxes do not match the location of your neighbor's boxes or install sockets and switches outdoor installation. Do not install plastic slopes filled with mounting foam. Mounting foam does not interfere with the penetration of noise from the street. Plaster window slopes. Install monolithic window sills (let's say stone). Install windows with double-glazed windows and different glass thicknesses. Such a minimum set of measures taken will allow you to significantly get rid of unnecessary noise penetrating the air.

2. Straight through the wall

This path has already been described above. Unfortunately, the thickness and massiveness of adjacent walls in our apartments is not sufficient for good sound insulation. interior spaces. Therefore, it is necessary to carry out additional measures for soundproofing adjacent walls. The main thing is to avoid rigid connections between the soundproofing structure and the main wall.

This can be achieved by using special fasteners or a fastening system for fixing the material, which makes it possible to fix the material in a vibration-decoupled (non-transmitting vibration) way. Plus, laying along the perimeter of the soundproofing system of soundproofing gaskets designed to perform the same task - not to transmit vibrations from adjacent walls, floors, ceilings to the soundproofing structure.

3. Indirectly through floors, ceilings, communication systems, structural units of the building

A sound wave, having arisen in one room, transmits its amplitude of vibrations to the air surrounding it. The air medium, in turn, transmits this amplitude to all solids with which it comes into contact. These are the walls and interfloor ceilings, And different kind nodes and communications of the building. Thus, the sound will pass not only through the adjacent wall, but also through the adjacent walls, as well as the floor and ceiling.

In order to get rid of noise penetrating indirectly, it is not enough to soundproof only one adjacent wall. In this case, you will have to go for a very financially costly way of soundproofing an apartment - creating a “room in a room”. In other words, you need to soundproof absolutely all walls, ceiling and floor. This method is expensive and requires the involvement of those with certain knowledge. After all, it will be a shame to spend a lot of money and get a “zilch” at the exit.