Brickwall

hi , i would like to insulate our hall from 200sqm, so I can use it for recording and concerts. The hall has a brickwall of 12cm, no plaster on both sides. I want to mount a 6cm insulation like rockwoll, and a 14cm wall of sand pressed stones. These stones do 54db of reduction. My problem is: what is the brickwall´s noise-reduction? If I know, that, I can calculate the overall reduction of the new wall. I need this to choose the best windows, to prevent noise leaks.

Hi G-slam, and welcome!

These stones do 54db of reduction.

Do you mean they have an STC rating of 54, or do you mean that they reduce transmission at a particular frequency by 54 dB, or are you referring to some other rating? I'm assuming that you mean STC?

If I know, that, I can calculate the overall reduction of the new wall. ...

Actually, it's not that easy! You can't just add up the STC values of two independent walls or building materials, and assume that the sum total is what you are going to get if you build a single MSM wall using those two! For starters, you are building a two-leaf resonant system, so it will no longer be mass law that governs Transmission Loss. TL will now be governed by the characteristics of the MSM system. You will get much better TL at high frequencies, and you will get WORSE TL in the low frequency range. The frequency, width and depth of that low frequency dip depend on a number of factors, mostly related to how you build the combined MSM wall. That alone will skew the STC rating one way or another. The dip may or may not be important in your case, but that depends on many other factors. There are equations that you can use to predict the TL and other characteristics of your MSM wall, but it is not as simple as saying "My blocks get me 54 dB STC, my bricks get me 43 dB (or whatever), so I have a total of 97 dB STC". It just doesn't work like that, unfortunately. I wish it did! You say that you want to isolate the room so that you can use it "for recording and concerts", but that doesn't say much. What are you recording? A single piccolo, a heavy metal rock band, a folk group, or an entire symphony orchestra? And regarding your concerts, do you mean harmonica concerts, or bass drum concerts? Are we talking Pink Floyd or are we talking Chopin? You also don't say how much you need to reduce the level by, on the other side of the wall. What is out there? Is it a nursery for a newborn baby, or is there a mile of empty landscape to you nearest neighbor? All of the above are wildly different scenarios, and nobody here can help you if you don't proved a bare minimum of information to work with. You might be overbuilding or you might be underbuilding, and either way is sad. You may not need a wall anywhere near as tough as you imagine, in which case you'll be wasting lots of money building it, and you may need something even more substantial, in which case you'll have to tear it down afterwards and build something better (or just live with a mediocre wall). There is an announcement at the top of the forum about what to do to assure getting as many responses as possible. The announcement leads to this post. Actually, several people who are experts on this forum will not reply at all if you do not do what is written in the post. Many others who are very helpful, will not reply out of respect for the moderators' wishes. Please read that and try to provide all of the information that you can.

I need this to choose the best windows, to prevent noise leaks.

If you are going to put a window in there, then that changes things hugely. The window will be your weak link, and needs very careful design. There isn't much point in having a wonderful wall with, for example, an STC rating of 72, if your very best window only gives you an STC of 52 (I'm just picking numbers out of thin air here: I have no idea if those numbers are representative of your wall or window). The overall TL of your wall is going to governed by the window, not the wall. It doesn't make sense to build a wall that is seriously better than the best window you can afford to put in it. Neither does it make sense to build the window much better than the wall. They should be designed for roughly the same TL. For the kind of wall you seem to have in mind, that window will have to be constructed with two panes of very thick laminate glass (different thicknesses), separated by a very large air gap, and extremely well sealed. That is expensive. And you didn't even mention doors, ceilings, or HVAC. Three other potential major issues. Anyway, please read over that link I gave you, and fill in the gaps so that folks here can have a better shot at helping you. - Stuart -

Further to that your avatar isn't working :P

g-slam wrote:

My problem is: what is the brickwall´s noise-reduction?

The existing brick wall is in the neighborhood of 45 stc. Hope that helps.

So my guess of 43 wasn't too far off! :) - Stuart -

Hi Stuart. Sorry for my quick post. I could send more information about the room, but I just want to know the general STC for this wall construct. And please excuse my english, I am learning the right terms like TL and STC right now. I build studios before, but it was always with gypsum boards and only necessary to build some more walls inside. We want to record Jazz and acoustical music, maybe som funk-soul-pop stuff, no Rock and Metal. The concerts will be between same genre of music. The halls dimsensions are 13mx15m, they ceiling is rising from 10m to 12m. The hall stays in the backyard, there are some cars parking, but this noises like starting engines and slamming door is heard in the hall. So we want to reach STC maybe 55-60, I know that the windows will be the sound leaks, but our budget is limited to 100k (€). The heating will be a into the floor mounted waterpipe-system. (dont know the english word). There is a studio proofed no-noise system. AC is not so popular in Germany, Ventilation will be installed. I will meet a professional studioplaner in the next weeks, to get more ideas, hints and tips. Maybe we let him do the plans, if we can pay it. I know, its not so easy to build, we are planning now for few months. Now is the time, where I know, what we need and want, so I can start to ask the experts. BTW, I was in SCL last february, my brother is living in Vitacura. I felt in love with this town..... P.S.: I think, my avatar is lost, since the forum moved...

That looks like a pretty decent sized space you have there! Wow! I'm jealous!

The halls dimsensions are 13mx15m, they ceiling is rising from 10m to 12m.

Dream dream!!!! Envy envy!!!

but this noises like starting engines and slamming door is heard in the hall.

OK, so you have a basic idea of your minimum requirements there! Those noises are probably mainly low frequency energy, so that's a good start: Since you also mentioned music genres that have low frequency energy, that will need to be one of your design criteria: Good low frequency isolation, such that vehicle engines and slamming doors right outside cannot be heard / pocked up by a mic inside.

So we want to reach STC maybe 55-60, I know that the windows will be the sound leaks, but our budget is limited to 100k (€).

I don't know much about construction costs in your end of the world, but it certainly sounds do-able on that kind of budget.

I will meet a professional studioplaner in the next weeks, to get more ideas, hints and tips. Maybe we let him do the plans, if we can pay it.

Excellent idea! And I would STRONGLY recommend that you call people like John Sayers, Rod Gervais, and other professional studio designers who are here on this forum, about that! You simply cannot find better studio designers, at any price, anywhere int eh world, and from what I've heard you will be probably be able to save MORE money than what their fee costs on a project this size, due to their wise use of resources and years of experience. They can show you exactly where to save money, and exactly where you should not try to save money. They know what works and what doesn't. They really could save you money, but even more important than that, you'd get an absolute top-quality world-class room. If you want the very best room for your budget, then call them. Seriously. - Stuart -

BTW, I was in SCL last february, my brother is living in Vitacura. I felt in love with this town....

Wow! Great! Vitacura is where I live! I'm just a few blocks from Clinica Alemana and Parque Arauco. It sure is a small world!!!

Pictures really are helpful when trying to get inside a far away project. There is so much detail on both sides of the screen that cannot be recalled all at once. If you have any pictures, post them so everyone here can have some input on areas that you may not be able to see. As always, good luck!

You are right. I will collect all available informations, like plans, dimensions and pictures. Then I will post it in a new thread, so its easier to read for everybody. Thanks.

So I started a new thread for my hall. Converting track repair to recording room I put some more infos and pictures into it.

BTW, I was in SCL last february, my brother is living in Vitacura. I felt in love with this town....

Wow! Great! Vitacura is where I live! I'm just a few blocks from Clinica Alemana and Parque Arauco. It sure is a small world!!![/quote] indeed, its great. The streets name is Brasilia. Do you work in a studio there? Maybe I visit you next time. We were joking about moving to SCL, my wife could work as a doctot in Clinica aleman, and I would look for work as engineer....