Does sound pass through bricks? Can I deflect sound away?

[kent davidge]

I happen to live in a complicated neighborhood where people will have parties lasting all the night. I was thinking about accoustically isolating my bed room.

Question 1:

Intuitively, I would say that most of the sound comes through the windows, some through the door and a neglibible part passes through the bricks that make up the walls.

If that is right, I would only need to buy a windows that will the block sound, as my ceilling is also made of bricks (I don't know how this is called in English).

Question 2:

Almost all my current knowledge is about EM waves, but I know that some features are shared by all kind of waves. In particular, the fact that when passing through a "hole" part of the incident wave is reflected back and part is transmitted through the hole.

Is there any realistic way I could have some device that reflects most of the sound coming into my room? That is, it would be like a mirror for sound. My guess is... it's not practical due to the large wavelength of sound waves. I would say this based on my understanding of EM waves though, so I'm not sure.

 

[Lnewqban]

You have the correct idea.
Some more here:
https://www.popularmechanics.com/home/interior-projects/how-to/g2470/soundproofing-a-room/

 

[berkeman]

I happen to live in a complicated neighborhood where people will have parties lasting all the night. I was thinking about accoustically isolating my bed room.

It's a bit of a hassle, but have you considered noise cancelling headphones? You could get ones with Bluetooth so you can use your cellphone and entertainment system, but still cancel outside noise.

 

[kent davidge]

It's a bit of a hassle, but have you considered noise cancelling headphones? You could get ones with Bluetooth so you can use your cellphone and entertainment system, but still cancel outside noise.

I do not think I would feel comfortable sleeping with them.

Do you have an idea of the percentage of the sound which is transmitted through the bricks though?

 

[berkeman]

I do not think I would feel comfortable sleeping with them.

Good point. And I'm usually not real comfortable sleeping with foam earplugs in either, since I need to be able to hear my alarm in the morning, and I would prefer to be able to hear and respond to any emergencies that might happen in the middle of the night.

Do you have an idea of the percentage of the sound which is transmitted through the bricks though?

I believe it is pretty low for true brick walls (after all, cinder block walls are used for "sound walls" alongside highways). Is it a true brick wall, or a brick facade layered onto a traditional wood framed wall? You can tell the difference because real brick walls have a "King Row" every 5th-8th row or so.

https://lh3.googleusercontent.com/proxy/F0WTYIGDg1go4b2vEuYwGndr3kurr7hujW0h548rLLPtlyxf-syyThnmyKYEc0gXJy_9vFO1_OqaGQp7oLCrHP96fav0CU3sh_8TrPALzGw82bcXUOUKIvy0l8Gi_sw_jqKvHsfWmPk

 

[berkeman]

I do not think I would feel comfortable sleeping with them.

BTW, there may be some low-profile earbuds with similar features to noise cancelling headphones. I don't know a lot about them, but it does seem like a feature that some earbuds might include.

 

[Keith_McClary]

If you know about impedance of cables, there is an acoustic version:

Table 1 shows the acoustic impedance of air and typical building materials.
...
2.3 Impedance.
Material Z0 (Rayls)
Air 413
Wood 1.57 × 106
Brick 7.40 × 106

Some ideas here:
https://soundproofliving.com/soundproofing-windows/
although I am skeptical of "window film" and #1. BLOCK THE WINDOW WITH FURNITURE

I sleep with pillows over my ears.

 

[kent davidge]

I believe it is pretty low for true brick walls (after all, cinder block walls are used for "sound walls" alongside highways). Is it a true brick wall, or a brick facade layered onto a traditional wood framed wall?

It is atually made of hollow bricks, pretty much like these

Some ideas here

I will take a look

I sleep with pillows over my ears

Do you have problems with your neighbors?

 

[DennisN]

I just want to jump in and point out that sound with lower frequency (i.e. bass) is generally more difficult to soundproof against. This is because the physical wavelengths are quite long. Bass sound is notorious for the ability to travel through structures.

I would also suggest noisecancelling headphones, like others have done above.

 

[sophiecentaur]

You can tell the difference because real brick walls have a "King Row" every 5th-8th row or so.

I hadn't heard the expression 'King Row' and I looked it up. It's strange - yet another difference between British and US practices - but wood frames and wood inner skins were not common in the UK until recently; "real brick walls" rule! You will find mainly Cavity Walls in the UK, with two 'leaves' (skins of brick or block) with an air gap between them and metal ties holding the two leaves together. Before cavity walls they used double thickness walls, with several methods of bonding them together. Flemish and English bonding used stretcher and header bricks arranged in various patterns. Good for low frequency sound screening because it's mainly mass that counts at low frequency. But LF sound was not a problem before modern music (except for heavy machinery in factories).

Cavity walls can be filled with foam or fibre but that can be problematic with damp, mould etc etc. Nowadays, in the UK there is much more construction in the US style with wood skins inside and brick outside.

I would think there's no way to modify the construction of just one floor or room in an existing building by adding mass because the floors would not hold the required weight / mass. A sealed box for sleeping in would need to be sealed so it could get very hot without some fancy ventilation (noise excluding).

I have used sound cancelling headphones and they are very effective. no good for sleeping in though; perhaps buds would be acceptable.

But the Environmental Health Officer may be your friend, if it's really that bad.

 

[berkeman]

"real brick walls" rule!

Not here in Earthquake Country! Real brick construction is pretty deadly here, and may even be against modern building codes now. If you see King Rows around here, you pretty much stay the heck out of that building.

Amusingly, the local large Fire Station looks like it's built with brick walls, but if you know to look for the King Rows, you can tell it's just a facade.

 

[sophiecentaur]

We live and learn. (Especially on PF)

 

[Keith_McClary]

real brick walls have a "King Row" every 5th-8th row

But there are fake "real brick walls" - see the last three pages here.

 

[berkeman]

But there are fake "real brick walls" - see the last three pages here.

Yeah, that's insidious, IMO. Brick buildings are a death sentence in Earthquake Country.

https://www.seattletimes.com/seattle-news/politics/will-seattle-at-last-take-action-on-buildings-that-can-kill-when-earthquakes-hit-new-push-in-seattle/

 

[nettleton]

I guess you have read of blast walls aimed to attenuate high intensity waves. Of interest is their reflection back towards their source. Perhaps fitting your brick wall with a lining of a more efficient attenuator of sound, possibly sheet aluminium, might help.

 

[sophiecentaur]

Perhaps fitting your brick wall with a lining

Two walls, separated by a cavity can work very well if the cavity is wide enough. The window between a recording studio and the control room is pretty effective and that's just two panes of thick glass, separated by a large gap. Ideally, the cavity should be filled with a lossy material such as open celled foam or fibre. The filling works by dissipating the energy of the moving air molecules. It could involve losing a fair bit of volume from your living room.
Problem is that, if you deal with the majority of nuisance sound in this way, you will end up with annoying amounts of low level 'tinny' sound, getting through gaps in the insulation. Doors and windows are only so thick and can have gaps through them. You could get paranoid about those low level intrusions!

 

[DennisN]

Ideally, the cavity should be filled with a lossy material such as open celled foam or fibre. The filling works by dissipating the energy of the moving air molecules. It could involve losing a fair bit of volume from your living room.

Yes. That is also what you can do in the interior of loudspeaker cabinets to attenuate the sound coming from the back of the speaker driver. The objective of the loudspeaker cabinet is to make as much as possible of the sound coming from the front of the speaker driver, and as little as possible coming (around) from the back of speaker driver, since the sound from the back would interfere and attenuate the sound from the front.

As for soundproofing rooms, an easy and quite widely used method in local band rehearsal rooms is to put up carpets on the walls and/or put up bottoms of egg cartons for additional deflection/absorption.

 

[sophiecentaur]

Heavy fabric is good for reducing reverberation in a room. Egg cartons are probably only slightly effective except for absorbing high frequencies and they are so light that there won’t be much effect on mid to low ranges.
Neither of those will have much effect on the thumps from loud rock music. Mass is what counts.
There is extra subjective annoyance from narrow bands of hf (tinny sound) and of (boom boom) when the actual music is not audible.
I’d bet that the OP could not / would not choose to spend enough on brute force architectural solutions. Electronic noise cancellation would be affordable but even that could fail to deal with physical thumping on the body of a listener from loud music.

 

[anorlunda]

Heavy fabric is good for reducing reverberation in a room.

Where appearance is important, heavy fabrics are an excellent way to deaden sound. If you hang the fabrics vertically, about 1 cm from the wall, they will absorb sound. But then you are free to pick the color, texture, pattern, or picture to suit decorative purposes. Think of the fabrics as an alternative to paint colors to set the mood for the room.

If you hang a lot of pictures, they can be hung from the fabric instead of directly attached to the wall.

 

[sophiecentaur]

Where appearance is important, heavy fabrics are an excellent way to deaden sound. If you hang the fabrics vertically, about 1 cm from the wall, they will absorb sound. But then you are free to pick the color, texture, pattern, or picture to suit decorative purposes. Think of the fabrics as an alternative to paint colors to set the mood for the room.

If you hang a lot of pictures, they can be hung from the fabric instead of directly attached to the wall.

Unfortunately we find that the sort of heavyweight fabric that would be effective is very expensive if it also has to have designs and colours that we want to live with. All walls need to be covered or you can get ‘flutter echo’ and incoming sound nearly as bad.

 

[Robert P]

It depends on how much sound reduction you'll consider to be enough. I'd suggest looking at an audio recording forum and what's involved in building an environment to keep outside sound out.

I built a sound booth - it's essentially a room inside a room. 2x4's, insulation, sheet rock - but I imagine that's not what you'll want to do. If anyone makes windows that will keep a significant amount of sound out, they'll probably be on the order of bullet-proof glass and not practical.

You might try what I did for the window in the spare bedroom where my sound booth is - I made a sound barrier "plug" - a frame out of 2x4's made to snugly fit in the window with acoustic ceiling panels covering the frame with insulation sandwiched inside. It's light enough that you could remove or put it in place pretty easily. It won't keep out all the sound but should cut down on it significantly. It works on my window because of how it's configured.

 

[Keith_McClary]

There are various philosophies, e.g.:

When it comes to isolation I've been told "mass air gap mass" is the way to go so no I would not fill the window completely.

In your case the glass and board would be the outer masses.

ajax57 at
https://www.gearslutz.com/board/studio-building-acoustics/1106241-dry-wall-rock-wool-block-window.html