# lgl`s soundproof HT



## lglura (Aug 25, 2008)

Hello all.
I`ve started to build my new HT, and i`m planning to build it soundproof.
The room will be supplied with traps an diffusors.
I hope to build a great room with great sound and no need for robbing my bank.
This was my old HT.


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## salvasol (Oct 31, 2006)

I'll be waiting for those pictures...:bigsmile:


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## lglura (Aug 25, 2008)

The last picture, the room is empty, only the concrete floor and walls.
Almost ready to start the build.
I`ll post pics and if anyone have any tips i`ll be very grateful.:hail:


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## lglura (Aug 25, 2008)

Thanks again Ted, this is realy helpful. I`ll share my plans in this thread.
I think i`ll have a great sounding room thanks to you all.
The room has two doors, i`ve moved one.


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## lglura (Aug 25, 2008)

One more question, how do i install the wall studs to the concrete wall.
Are resilient clips an option.:help:


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## Ted White (May 4, 2009)

Wall studs would not contact concrete wall = decoupled

There are two types of clips. One decouples the frames wall from the joists overhead. This is the DC-04 clip.

The other clip you may be more familiar with is the sound isolation clips like the PAC RSIC-1 or WhisperClip. These isolate the drywall from the stud wall

If the wall itself is separated from the concrete you would benefit from the DC-04s but not the Sound isolation clips


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## lglura (Aug 25, 2008)

Ted White said:


> Wall studs would not contact concrete wall = decoupled
> 
> There are two types of clips. One decouples the frames wall from the joists overhead. This is the DC-04 clip.
> 
> ...


Thanks Ted.
The wall itself is separated from the concrete wall, the DC-4 looks great, how many clips should i use in the wall.
lgl


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## Ted White (May 4, 2009)

Every 3-4 feet along the top plate of that wall. Again, the stud wall is maybe 1" from the concrete. With a little R13 fiberglass. Then drywall right to that stud wall.

The heavier that wall is, the better. Double 5/8" drywall is perfect


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## lglura (Aug 25, 2008)

Do not need two windows, blind both. Now i have better lightcontrol.
Almost ready to start the build.


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## Space (Jul 18, 2007)

The only issue with walls inside of walls, lgl, is that this type of build can eat up a lot of floor space and quickly. Sure it does what it does, but is it what you require for the best isolation based on your budget.

And take that low ceiling height into consideration...it only gets lower from here 

Adding mass to the upper floor area is a good thing and can reduce sound penetration from upstairs to downstairs, and vice-versa. That should get on your radar screen first no matter what you do.

Have you taken any sound measurements around the house, inside/outside to determine what it is you are up against as far as noise levels go?

Another blip on the radar screen just appeared 


You have an idea of what you want I can tell, so plan out all the steps before you take them is my suggestion.


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## Ted White (May 4, 2009)

I agree you should have a plan before the nails and screws fly. Not convinced anything would come out of measuring the sound beforehand. 95% of the time casual HT-ers are looking to simply keep as much sound in as possible, not vise-versa.

There are space conserving sound isolation construction techniques.


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## Space (Jul 18, 2007)

What would come out of measurements Ted, is knowledge. Knowledge that you are up against a specific noise level. That in itself allows others that can help, like you, to know with better accuracy what the build will require.


Just for the record, 75% of statistics are made up on the spot


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## Ted White (May 4, 2009)

Space said:


> What would come out of measurements Ted, is knowledge. Knowledge that you are up against a specific noise level. That in itself allows others that can help, like you, to know with better accuracy what the build will require.


You would spend $ in this budget build to buy equipment to measure the noise coming off the washing machine?

I could be all wrong here, but I believe LGL is looking to keep sound in, not out. A background sound measurement isn't helping.


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## Space (Jul 18, 2007)

I would spend 100 dollars to save 100 dollars, yes sir. HT rooms are indulgent to begin with, so waste is subjective.

Also, I will not attempt to measure what is in the head of another human being, too many unknowns. So you are on your own


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## lglura (Aug 25, 2008)

Hi guys.
My biggest problem is to keep the sound in. I`m live in a quiet neighbor relationship and i am the neighbors nightmare:hush:.
The reason why i am building this soundproof HT is when i tested one Tubesub!!!( i have two) my wife open the door and screaming that either i had to turn down the sound or do i need to glue the plates to the shelves and buy a kidney belt:rofl:.
I have good plans for the room (thanks Ted for your heads up) the biggest problem is to keep the vertikal height. I will describe later


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## Space (Jul 18, 2007)

Thanks Lgl, it may not be a test but it helps those looking on who are not as insightful.


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## Ted White (May 4, 2009)

Keep in mind you're still going to hear subs.
_Posted via Mobile Device_


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## Seb (Apr 22, 2006)

A "background" measurement will tell the builder how quiet it is on the receive sound, i.e. how much noise reduction will be required between the room and the receiver.

He could also measure how loud the sub currently is at the receiver location - then he will know how much additional transmission loss is required.

The problem with cheap sound level meters is that they will not be sensitive enough to measure the quiet background sound level. Another problem is that they may not have the frequency extension down to sub-territory (60Hz and lower). Even an ECM-8000 hooked up to a laptop or computer may not measure low enough in level (say less than 35dBA) although it will work down to 20Hz - then need to read up on how to calibrate the measurement system.

In terms of a room-within-a-room, saving space is the opposite of what is needed to control low frequency sound. That is why it is important to measure first, work out the TL required (i.e. obtain the necessary knowledge) and then design&build.


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## paulspencer (May 11, 2007)

As I see it there are *TWO *problems you should consider at the same time - one is keeping the sound in, the other is creating bass absorption! If it were possible to build a room that can keep all the bass in the room, it would sound awful. Bass absorption makes the task of getting good bass sane. Many are forced to use bass traps, but don't realise that the ideal is that the entire room acts as a bass trap. This actually works fairly well with the goal of sound isolation. Multiple layers of drywall with a flexible adhesive in between (like liquid nails) works well. 

Your room looks very solid, and I suspect a real challenge. I'm expecting some serious peaks and dips in the response. If you can get some more bass damping then you can reduce the challenge down to something you can work with. 

You should pay careful attention to any weak points that will "leak" - doors, windows and any penetrations (power points, downlight holes, services/ducts etc). 

Bass is always going to be a challenge to keep in the room. 

This may be a challenge, but ideally you want to build a false ceiling that does not touch the existing one at all - neither the structure nor the drywall. Of course, there are different systems available that are low profile. You can attach drywall onto low profile metal frame work with special mounting systems. I've looked into those in the past and the cost can really hike. Another factor is whether this is DIY or not. 

Topics like these are covered in a book by Dr Earl Geddes
http://www.gedlee.com/Home_theatre.htm

I don't know of anyone else who actually has a PHD related to small room acoustics. Much of what is published about architectural acoustics is suitable for large scale applications, not domestic home theatres.


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## Ted White (May 4, 2009)

This is getting a bit overboard for lgl. 

There's nothing to measure up front, since you have no specific sound you're looking to block.

You can incorporate treatments and traps after you build.

Just follow the basics of room construction (as inumerable others have) and build the best walls and ceilings you can. Decouple, absorption, mass and damping.


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## lglura (Aug 25, 2008)

Wow guys, i think i `ll describe the build soon. i need a simple program to sketch it.
I`ll build the room airtight with no leaks, floating ceiling on floating walls attached with resilient clips to the concrete and a floating floor inside the wall. I`ll have two airtight doors. There is no weak point exept to little vertical height ( i hope). The acoustic treatment will be carried out when the room is done.


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## lglura (Aug 25, 2008)

Ted White said:


> Keep in mind you're still going to hear subs.
> _Posted via Mobile Device_


I can live it as long as my wife is happyaddle: and i can watch movies without any limitations:R


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## paulspencer (May 11, 2007)

Is this a DIY project or are you having it done? This can have a big impact on the cost. If not diy, then labour cost will have a greater impact on budget. 

When I looked into isolating mounting systems in the past, the cost was very high. It's a low profile option and the cost can look different if labour is factored in. However, if you can actually use staggered ceiling joists for example, you can completely isolate the false ceiling. Done cleverly, this will also be a low profile option where the staggered joists protrude just below the existing ceiling members. That would be my first choice in a DIY situation.

Bass traps are intrusive into a room, and it makes sense to try to turn the entire room into a bass trap. In essence, this is what we are doing in using drywall and isolating it from the existing cave-like envelope. So while I tend to disagree with ignoring the bass damping issue, thinking you can fix it later with bass traps, this is moot because isolated drywall walls and ceiling will in fact increase bass damping a great deal. 

In terms of measuring, it actually makes sense. This allows a before and after - which you can't do later. You could measure sound transmission loss as well as internal acoustic response. Both will have value, and will give you some feedback on what you have achieved. You can't do this later if you get curious!


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## Ted White (May 4, 2009)

What a great reply. I agree with all these points. Maybe not so much the measuring part, I'll admit. But for sure very good point about the decoupled system absorbing low frequencies. 

You rarely hear about this. The max absorption occurs at whatever low frequency resonance point is present in a given partition. And you have the bell curve move out from there. Further away from the fundamental LF resonance point and absorption drops as well. I was involved with testing this very thing at Orfield Labs in Minneapolis.

This is all excellent that you brought this up as we're seeing amazingly large IB systems much more routinely, and of course this means they need more LF absorption as you say.

Do you like to use theater risers as bass traps? I'm not an in-room acoustics person but this topic comes up frequently.


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## Ted White (May 4, 2009)

lglura said:


> I`ll build the room airtight with no leaks,
> 
> Tough, but you know that obviously​
> floating ceiling on floating walls
> ...


When these two doors are closed, are they side by side or is there an airlock created?​


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## Space (Jul 18, 2007)

The issue with any speaker that can generate enough pressure to rattle plates is that it had to rattle the structure to rattle the plates 

Ted will be the first to say that before a build starts you should add additional mass to any and all areas that are part of the exterior leaf if possible. The interior leaf will not be effective enough to completely isolate the heavy rumblings of a sub woofer if this attention is not granted.

Is that not a fair assessment Mr. White? Windows, doors, that overhead floor and possibly the chimney should have a good look into before, if this were me, the build actually began.


Just trying to help you have the best you can Lgl.


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## paulspencer (May 11, 2007)

> What a great reply. I agree with all these points. Maybe not so much the measuring part, I'll admit. But for sure very good point about the decoupled system absorbing low frequencies.


Thanks :bigsmile:
I'm a little surprised about the measuring part. If you're talking about measuring the ambient noise level, I don't see the point. If we are simply talking about sound proofing, then all it will do is show what you have achieved. I'd say that's worthwhile, mainly for the sake of curiosity. Especially when one wants to see what happens at 50 Hz! Probably a bit disturbing ...

The most benefit in measuring will come when the room is actually done, and it's time to work on the bass.

This is a simulation of a room that I used in the past:










The dotted line shows worst case scenario if it were built like a bomb shelter/garage. The magenta line shows a more typical room. This would be easy to eq mostly, except two deep nulls. The red line shows what we want to see - a room where the modes are sufficiently damped that we have a good chance of getting it right with eq. 

Of course, you can't rely on simulations, but they are illustrative still.

These settings were used to show the eq required to get the bass flat:










Note the actual room response is the inverse. As you can see, it's pretty tame. This is a lossy room with timber floor and light timber framed drywall as well as double glass doors and reasonably large windows. No bricks or concrete. 

The two charts above are for the same room. Keep in mind the eq/measured chart is more complex also as it has mains and subs overlapping, the mains able to get down to 23 Hz. 

So if you get the room right first, this should be the first thing for the bass. Then I'd experiment with eq and placement. There's a good chance this will get a good result. Ideally if funds permit you'd do this in conjunction with a multi sub arrangement. Here is a measured example:

http://mehlau.net/audio/multisub_geddes/

Geddes suggests 3 subs are ideal. You can start with one sub which mostly meets your performance demands on its own. It's placement is less critical since it will most likely operate below problemmatic zones. The other subs will give some boost, but their main function is to improve the room response by "spatial averaging." They can in fact be compact, and this is a good place to diy since you can cleverly hide them if desired, and integrate them into the room creatively. You could have a stair riser sub, coffee table sub etc. 

If after doing all this you are still having a case of audiophilia perfectionitis, then it's time to think about adding bass traps. 



> Do you like to use theater risers as bass traps? I'm not an in-room acoustics person but this topic comes up frequently.


The idea makes sense, but I haven't done it due to practical restraints. I also don't actually need add on bass traps. Chances are I will experiment with them to see if I can get an improvement. In that case I'd certainly measure before and after.


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## Ted White (May 4, 2009)

Space said:


> Ted will be the first to say that before a build starts you should add additional mass to any and all areas that are part of the exterior leaf if possible. The interior leaf will not be effective enough to completely isolate the heavy rumblings of a sub woofer if this attention is not granted.
> 
> Is that not a fair assessment Mr. White?



That's fair, sure enough. Having said that, you could mass load the existing structure, decouple, mass load the second inner structure and still hear bass. It is not likely that the resonance point of the resulting new assembly will be lower than 30Hz. This means we won't have as much effect on frequencies below 45Hz. 

That's what I was meaning several posts ago. You're still going to hear the low bass, since it just isn't practical to build partitions whose resonance point is extremely low. Too much air cavity depth and mass is needed.


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## Bruce Fisher (Nov 24, 2007)

this is very educational! good stuff!


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## lglura (Aug 25, 2008)

What can I say, I am very grateful for all the answers.:hail::hail::hail:
I am not a beginner, and certainly not an expert, so please contribute, even if it flies over my head.
I would agree, this is very educational.


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## lglura (Aug 25, 2008)

Ted White said:


> When these two doors are closed, are they side by side or is there an airlock created?​


It will be an airlock between the doors, indipendent ceiling joist as in the article.
I plan to build a floating floor for insulation and decoupling.
I shall try to describe with a sketch before the nails and screws fly


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## Ted White (May 4, 2009)

I would not take up valuable headroom for that floor.


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## lglura (Aug 25, 2008)

I know it but I need to isolate, it is cold in Norway


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## Ted White (May 4, 2009)

You're below ground? Or no? Cold in the states and canada as well but a few feet below ground it's all same temp all year. Small point, as many do this for thermal comfort nonetheless.


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## lglura (Aug 25, 2008)

Ted White said:


> You're below ground? Or no? Cold in the states and canada as well but a few feet below ground it's all same temp all year. Small point, as many do this for thermal comfort nonetheless.


Have not thought of this, the floor in the room is two feet below ground. 
Possible a thick carpet is solution,I get two inches extra ceiling and the height is 230 cm.


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## Space (Jul 18, 2007)

Ted White said:


> That's what I was meaning several posts ago. You're still going to hear the low bass, since it just isn't practical to build partitions whose resonance point is extremely low. Too much air cavity depth and mass is needed.


I am a bit confused on what it is you are saying then.

I saw a guy(Lgl) that is doing a remodel on an existing ht...there is a reason people do this  And at least part of that reason is house rattling not in the basement...in the upstairs area. But we did not know this for sure until the ground shaking subs were mentioned, after the measurement comments.

Your preaching to the choir. It is the easy answer to mention doing a room in room construction, it can be the most effective weapon against low frequency energy. But all parts of the build must be entertained as being interactive with this wall system or it is just another wall that isolates but does not address the specific issue/problem that seems to be the current concern.


In a nutshell, that is all I am saying


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## Ted White (May 4, 2009)

Adding the mass as you pointed out is a good idea. I am saying that you cannot build a room in any basement that will completely stop low frequencies even after adding said mass.


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## paulspencer (May 11, 2007)

From a thermal comfort point of view, a concrete floor on the ground is a good thing. It acts as thermal mass, and when the room is heated it stores the heat - a flywheel effect. Some houses are designed with this in mind to avoid or eliminate conventional heating. It also works in cooling. Radiant cooling is the most natural and pleasant kind - ever been down deep in caves on a stinking hot day? Feels better than an air conditioned room. Of course, in a cold room it will feel cold, but rugs where you put your feet will help. 

Concrete is very reflective acoustically, and should have something to tame it since the ceiling will normally not have anything. There are two schools of thought on acoustic treatment in general:

1. The first is the only one that many seem to know. Use whatever speakers you like best without considering the room as a factor then make the room fairly dead. Use a lot of acoustic treatement, mostly to absorb, but also some diffusion, with specific focus on the reflections that will cause the most problems. 

2. Choose speakers with a room interaction which is optimal in a normal room. Speakers like dipoles, omnis or with controlled directivity and a very well behaved polar response. In this arrangement, reflected sounds are desired and radiated in a controlled and planned way, rather than trying to just kill them. You might still use treatement with this approach, but it becomes less critical.


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## paulspencer (May 11, 2007)

Quick thought about the shaking things upstairs - what happens if you lay the sub across a couch? This will mechanically de couple it - what kind of difference does it make?


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## Space (Jul 18, 2007)

That is an area that may need some thought. I don't know if I would give up a whole couch to the sub even if the couch could do the job but it needs decoupling to reduce the structure borne vibration.

It may be as simple a thing as volume reduction.


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## lglura (Aug 25, 2008)

Volum reduction or sub across the couch, sorry but it is not an option.:nono:
I begin to understand how to build the room, i will describe it when I'm back from vacation, traveling tomorrow.
lgl:wave:


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## Space (Jul 18, 2007)

You cannot turn down the volume?


It's your hearing your talking about losing...not if, but when.


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## lglura (Aug 25, 2008)

Space said:


> You cannot turn down the volume?
> 
> 
> It's your hearing your talking about losing...not if, but when.


Appreciate your concern Space, but the volum is not that loud.
:heehee:lgl


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## Ted White (May 4, 2009)

So I assume the Holiday went OK?


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## lglura (Aug 25, 2008)

Ted White said:


> I would not take up valuable headroom for that floor.


Hi Ted.
How much difference will 7 cm represent if I lower the floor, the room is 730x330x223 cm.
lgl


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## Ted White (May 4, 2009)

Are you suggesting removing the concrete floor and re-pouring? I'm confused... sorry.

7cm isn't a lot of height to gain considering the work involved. Again, I'm probably misunderstanding


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## lglura (Aug 25, 2008)

Ted White said:


> So I assume the Holiday went OK?


Yeah Ted, was a trip in France and the holiday went OK, and now i am ready to continue with my build.
lgl


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## lglura (Aug 25, 2008)

Ted White said:


> Are you suggesting removing the concrete floor and re-pouring? I'm confused... sorry.
> 
> 7cm isn't a lot of height to gain considering the work involved. Again, I'm probably misunderstanding


Sorry Ted, but I have problems to explain me properly, will try to be clearer.
I`m not removing the concrete floor and no re-pouring. The height between the concrete floor and roof beams are 230 cm. Between this I will build floating ceiling and floor, and the space is limited.
lgl


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## Ted White (May 4, 2009)

Well ceiling height is always a desired thing. So I would see if you could avoid losing the 7cm


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## patchesj (Jun 17, 2009)

Very interesting points on mass and isolated walls to absorb low bass... Out of curiosity, what *would* be an effective air gap/wall mass to absorb <45Hz? Are we talking 3x or 4x 5/8th drywall? something heavier??


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## Ted White (May 4, 2009)

This can be calculated, but it's along the lines of a foor or two of airspace and 6-7 sheets of drywall on each side. Shocking, really


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## patchesj (Jun 17, 2009)

Ted White said:


> This can be calculated, but it's along the lines of a foor or two of airspace and 6-7 sheets of drywall on each side. Shocking, really


Interesting. Would using MDF, concrete board, or some other high density material be of benefit? I would think that creating a sandwich of materials with varying densities would broaden the absorption properties of the wall.


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## Ted White (May 4, 2009)

Not really. The resonance of the system is defined by the whole system, not the parts. Mass is mass. If well damped, there's no advantage to using dissimilar densities of mass in a leaf.

The LF resonance point calculation looks at:

Decoupled leaves?

Total Mass added

Absorption in cavity?

Air cavity depth (which is related to absorption).


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## patchesj (Jun 17, 2009)

I wonder how much depth lgl has at the rear wall of his room? In my case the rear of the room backs up to a storage area. Creating a high mass floating wall (2x4s with single drywall on both sides filled with some high density material like sand OR 3-4 layers of 1" MDF, not tied to the side walls or ceiling??) in front of a 2' filled cavity (fiberglass or cotton?), with the final isolated double drywall behind that would create this low frequency absorber?


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## Ted White (May 4, 2009)

Absorber is a term generally used to describe a treatment of sound remaining in the room. The sound we're describing has sufficient energy to enter (and leave) the room.

The object is to build partitions with as low of a resonance point as is practical.

Decouple the framing with a double stud wall.

Have as large a gap as possible between the two frames

Add absorption with standard R13 iberglass.

Add mass, generally double 5/8" drywall

These are the factors that lower that resonance point. Keep in mind that we're only able to significantly affect frequencies at 1.5X the resonance point and up. So if a wall had a resonance point of 60Hz, we're going to start to see a drop in performance at 90Hz and below.

Also your earlier question about a 45 Hz wall would be more along the lines of a 1' air cavity and 3-4 sheets of drywall. That's a guesstimate this morning.


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## patchesj (Jun 17, 2009)

Now that I think about it, trying to absorb frequencies that low would be very difficult. My original concept was to allow a mass in the room to be "moved" by the pressure waves and try to dampen/translate the energy (a tuned mass damper??). And this is why I'm not a professional...


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## Ted White (May 4, 2009)

I admire your thoughts and questions patchesj


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## lglura (Aug 25, 2008)

Hello again. Thanks for all the feedback in this thread,
have finally realized that it is not possible to build the room completely soundproof.
Thanks to all the feedback I now know how to build the room.
I will build it as solid as it is possible within the limited space I have, walls and ceiling get 2x 1/2 " drywall and 1x 1/2" MDF and green glue between the layers. I come back with pictures to describe the build:bigsmile:


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## patchesj (Jun 17, 2009)

Looking forward to the pictures!! Good luck and keep us informed. Out of curiosity (maybe I missed it in the thread), why 1/2" drywall, why 1 layer of MDF, and what will the sandwich look like (dry W, dry W, MDF? or MDF in the middle?).

Thanks


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## lglura (Aug 25, 2008)

patchesj said:


> Looking forward to the pictures!! Good luck and keep us informed. Out of curiosity (maybe I missed it in the thread), why 1/2" drywall, why 1 layer of MDF, and what will the sandwich look like (dry W, dry W, MDF? or MDF in the middle?).
> 
> Thanks


Hi patshesj. It is drywall/drywall and MDF as the inner wall plate and i`ll use 1/2 " because it is the cheapest solution, 5/8" comes only in fire-plate design.
This is the type of MDF wall plates I`ll use
lgl


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## Ted White (May 4, 2009)

So this is a 1/2" total thickness product? If so, I really recommend to increase the mass by adding a thick sheet of drywall behind that finished material.

Are you planning to incorporate acoustic treatments on the walls? Often the walls are completely covered with treatments. In that case there's not much use in applying a finished panel like you're showing.

Just trying to fully understand what you're goals are.

Thanks,


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## lglura (Aug 25, 2008)

Ted White said:


> So this is a 1/2" total thickness product? If so, I really recommend to increase the mass by adding a thick sheet of drywall behind that finished material.
> 
> Are you planning to incorporate acoustic treatments on the walls? Often the walls are completely covered with treatments. In that case there's not much use in applying a finished panel like you're showing.
> 
> ...


The total thickness in wall and ceiling is 1/2" DW+ 1/2" DW +1/2" MDF= 1.5". 
This is what I have found out thanks to all posts in the thread, and because of limited space.
The acoustic treatment is the last thing I do, and I shall not cover the walls completely.
Grateful for your participation Ted:T
lgl


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## Space (Jul 18, 2007)

Ted White said:


> So this is a 1/2" total thickness product? If so, I really recommend to increase the mass by adding a thick sheet of drywall behind that finished material.



If I may ask, what would be the difference between 2: 1/2" and one thick sheet? I mean, what is the difference in terms that I can understand as a builder of rooms.

Granted I wouldn't put the MDF on the inside of the room, but it is treatable It would be better situated as the first layer, but that's just from what I know.


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## Ted White (May 4, 2009)

Well, that's a really great question. 

From a mass perspective it's a wash, let's just say. Two 1/2" pieces = the weight of one 1" panel. But splitting that mass up gives you the opportunity to damp the panels with a damping material. 

If you were not going to damp, then having two dis-similar thicknesses of the material would break up resonance better.

Three layers of 1/2" mass (damped) is better than two 3/4" layers of (damped) mass, which is better than a single layer of 1.5" undamped mass. Why would three thin layers of damped mass be better than two thick layers of damped mass. Why?

Multiple dmping layers work better than a single layer. Even if the total amount of damping material remains the same.

Also, people use MDF on walls all the time, especially on the recording studio side of things. It's just an awfully expenside source of mass. We often recommend using a 7/16" OSB, then 5/8" or double 1/2". This gives you a nail base everywhere later when studs are hard to find


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## Space (Jul 18, 2007)

If damped.

This report:
http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/02-108.html
that is the conclusion of this data:
http://irc.nrc-cnrc.gc.ca/pubs/ir/ir761/ir761.pdf
reads that, based on the research, 13mm fire rated is recommended....if available.


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## Ted White (May 4, 2009)

That's a bit of a misleading recommendation they have and certainly not generally heeded advice. Otherwise we'd all be building our walls with lighter 1/2" board. But we don't (unless like lgl we use multiple 1/2" layers)

Mass law is a law, and 1/2" and 5/8" drywall are both sources of mass. Heavier 5/8" will outperform lighter 1/2" if we look at the larger sound spectrum.

One conclusion they derive is to use denser and thinner board. Technically, this is a great recommendation. The thinner panels allow more flex = more internal friction = more damping. Vibration is converted to heat. This is a good thing. And they pick up on the fact that 1/2" board is denser than 5/8" and thinner (flexible). However, 1/2 while more flexible and more dense is also lighter. And that it what swings the pendulum back in favor of the 5/8". 

I also _think _they were considering the data produced from 16" OC wall tests, which are inherently stiffer frames (less flex, less internal damping) vs. the more flexible 24" OC framing. If a 16" stud wall is being used, the 1/2" gets closer in performance than 5/8" because it can flex better on a narrow 16" stud spacing than can the stiffer 5/8".


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## Space (Jul 18, 2007)

Thanks for the verification. I think the National Research Council of Canada is a gold mine of information for audio related builds for people that choose to use it.


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## patchesj (Jun 17, 2009)

Wow Ted, that is some good info. So if you were designing the "perfect" (but reasonable) wall, what would it be? 1/2 DW", green glue, 5/8" DW on a 24" OC frame? Would using different thicknesses out weigh additional mass of a 5/8" X 2 wall?


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## Ted White (May 4, 2009)

Hi Patches,

I should mention that if you damp the system with a damping material, the whole 1/2" vs. 5/8" goes out the window. A damping material will damp far more efficiently than the board itself,

Given that, what I would recommend for a single stud wall (you mentioned) is 24" studs and double 5/8".

I would not recommend a single stud wall, however. A single stud wall is still coupled. I would recommend at least a staggered stud, and preferably a double stud wall to introduce decoupling.


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## patchesj (Jun 17, 2009)

Ah yes, I was assuming an isolated wall. Another crazy question, what about using green glue between the studs and first layer of drywall as well as between sheets? Any benefit?


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## Ted White (May 4, 2009)

Intuitively damping material would prove beneficial on the edges of studs and joists. There's insufficient surface area and little damping occurs there.

When used on a much larger surface area between sheets of drywall very efficiend damping can take place.


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## Ted White (May 4, 2009)

So... any updates?


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## lglura (Aug 25, 2008)

Ted White said:


> So... any updates?


Hi Ted. There is no update, have been very concerned with maintaining the house exterior. Begin to build walls in two weeks.
lgl


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## Ted White (May 4, 2009)

Better to do the exterior walls now


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## lglura (Aug 25, 2008)

There was bad weather:yay2:, so I worked a little inside. cut 1 inch of the roof beams in order to gain more headroom









To compensate for the weaker beams I glued on the reinforcement


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## Ted White (May 4, 2009)

Wow. You are one adventurous fellow!


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## lglura (Aug 25, 2008)

Cut 1 inch and not more, otherwise I'm on thin ice :hide:


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## lglura (Aug 25, 2008)

Finally I got it going again, and have begun putting together the walls.


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## Ted White (May 4, 2009)

Interesting clips. What are they? Just to anchor to masonry?


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## patchesj (Jun 17, 2009)

What is that membrane installed behind the wall?


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## rickp (Jan 14, 2008)

I have fully decoupled my HT room, the walls and ceiling are not touching any member of the house. It is a free standing room inside another room. I am very pleased with the sound proofing, Even with my system playing louder than I would listen to it the sound outside the room is barely audible, that is until I turn on the IB subwoofer. At that point the whole house shakes like King Kong is standing on it! http://www.hometheatershack.com/for...n-construction/16240-lake-martin-theater.html


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## lglura (Aug 25, 2008)

Sorry guys, i did not describe the last pics.:whistling:
It`s resilient sound clips to decouple and anchor to masory.
The memran is to keep the insulation in place, it`s airtight but moisture-open.
The rubbersheet is to decouple between the floorplate and the concrete.


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## lglura (Aug 25, 2008)

rickp said:


> I have fully decoupled my HT room, the walls and ceiling are not touching any member member of the house. It is a free standing room inside another room. I am very pleased with the sound proofing, Even with my system playing louder than I would listen to it the sound outside the room is barely audible, that is until I turn on the IB subwoofer. At that point the whole house shakes like King Kong is standing on it! http://www.hometheatershack.com/for...n-construction/16240-lake-martin-theater.html


Your HT room is very impressive, i`m very excited about the result after i`ve finished the HT.


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## chadcummings (Apr 26, 2008)

Looks good.

What will you be loading into the cavities in the walls to increase sound absorption?

My build will be a little different as I will be using 6" SS walls filled with either OC703 or acoustic cotton and 2 layers of drywall decoupled by green glue.


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## lglura (Aug 25, 2008)

chadcummings said:


> Looks good.
> 
> What will you be loading into the cavities in the walls to increase sound absorption?
> 
> My build will be a little different as I will be using 6" SS walls filled with either OC703 or acoustic cotton and 2 layers of drywall decoupled by green glue.


Hi. I`ll use the Roxul stone wool insulation, 2 layer drywall, 1 layer MDF and decoupled by green glue.


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## lglura (Aug 25, 2008)

Adding stringers to the longest wall to make it stiffer. I`m not shure if i should add stringers to all the walls. If the walls are moving at low frequencies, they will then absorb low-frequency sound?:scratchhead:


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## chadcummings (Apr 26, 2008)

I think you best bet for sound absorbtion of LF is to build it in it's own building next door.

Just kidding. LF is very hard to stop but it looks like you are doing a lot to reduce it.


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## lglura (Aug 25, 2008)

chadcummings said:


> I think you best bet for sound absorbtion of LF is to build it in it's own building next door.
> 
> Just kidding. LF is very hard to stop but it looks like you are doing a lot to reduce it.


Heh, heh Chad, I do not think the neighbor agrees to the ideaaddle:


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## Ted White (May 4, 2009)

Side note. You are not looking for stiff walls. Looser walls remove more low frequency bass


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## lglura (Aug 25, 2008)

Thanks a lot Ted, I'll try to build a compromise between stiff and flexible walls.


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## Ted White (May 4, 2009)

Yea, somehow "super-stiff" surfaces became a goal for some. The trouble is it just isn't possible to get an infinitely stiff structure.

Flex is what isolates. Allows internal damping of materials.


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## lglura (Aug 25, 2008)

I think I make the right choices for solutions, but I do not know this until everything is finished and begin the soundcheck, there are too many factors that affect this.


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## lglura (Aug 25, 2008)

Wall mounted until the neighboring rooms. 








There are about 1 inch between the walls.








The door is a 40 db sound proof, it is so heavy that I have trouble lifting it.








Cheers. some luxury do I need while I'm working:R


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## patchesj (Jun 17, 2009)

What are the details on that door?


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## lglura (Aug 25, 2008)

it is an approved door that will withstand heat for more than 30 minutes and dampen sound with a minimum of 40 db


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## Ted White (May 4, 2009)

lglura said:


> ... and dampen sound with a minimum of 40 db


I'm sure it's a great door. For the greater audience, these stats are misleading. 40dB at what frequencies? A sealed hollow core door will stop 40bB at some high frequency as well. No door will stop 40dB at 50Hz, in contrast.

Again, it looks like a fine door, and I'm sure it will work fine, simply commenting on their information


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## lglura (Aug 25, 2008)

Ted White said:


> I'm sure it's a great door. For the greater audience, these stats are misleading. 40dB at what frequencies? A sealed hollow core door will stop 40bB at some high frequency as well. No door will stop 40dB at 50Hz, in contrast.
> 
> Again, it looks like a fine door, and I'm sure it will work fine, simply commenting on their information


Yes Ted, probably in the range 3-4 k.
lglura


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## lglura (Aug 25, 2008)

Have tried to find detailed specs on the door but it is not possible.


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## lglura (Aug 25, 2008)

The building is a bit slow at the moment, here is an update. The walls are ready to be covered with drywall. The next thing I will build is the floating joist.


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## lglura (Aug 25, 2008)

I am a little confused, I will build the roof with 2" 6 " or should I build the roof with 2" 4 "to get a roof that is more flexible. I`ll use stringers between the joist (c/c 30 cm) in both cases . The weight of the roof is 23 kg each m2 :scratch:


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## Ted White (May 4, 2009)

Hi lgl.

I'm still not sure what the stringers are doing for you other than stiffening surfaces you'l like to have more flexible.

As far as which lumber to use, I would not consider less than 2x6. Your ceiling could sag or worse.


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## lglura (Aug 25, 2008)

Hi Ted. Stringers in the walls and roof ensuring that it does not bend when the timber dries, 
and because it is stiffer, I've compensated by using thinner studs (2" 3"). The walls are not very stiff.
The walls have different mass and flexibility, the wall behind is not made with stringers and the timber is 2" 4". I hope this structure functions as bass traps with different resonances.
(forgive me if my English is poor:rofl2


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## Ted White (May 4, 2009)

Thanks. English is great, actually and thanks for continuing to share your build with us!


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## lglura (Aug 25, 2008)

Of course I will share my build with the shack, and thanks for your help Ted, it has been a major contribution.


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## lglura (Aug 25, 2008)

The floiting joist is finished, stringers is not to make the joist stiffer but to prevent it to bends when they dries. I used 1.5" x 6" timber. All are on the straight line.















Has created a cutting board to cut the insulation, this simplifies the customization.


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## MatrixDweller (Jul 24, 2007)

If you're going to drywall the ceiling you should put it up first before you do the walls. That way the walls drywall gives a little support to the ceiling drywall. After the ceiling then you do the upper wall with full sheets then the lower wall with sheets cut to fit with factory edges always joining another factory edge. That makes taping and mudding a lot easier.

The stringers in the walls are used to stop fire (if one were to occur) from spreading up the wall cavity. They are not necessary if the cavity is filled with mineral wool. 2x4 is standard for stud walls but you can use 2x3s on non supporting walls and even 2x2s on a basement wall like furring strips. Even with spacers in the walls they can still warp. A little bit of warp isn't going to hurt much. The drywall in place with screws will prevent some of that.

Having the spacers in there isn't going to hurt anything. It's just going to make it harder to stuff with insulation.

Just my 2 cents


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## lglura (Aug 25, 2008)

MatrixDweller said:


> If you're going to drywall the ceiling you should put it up first before you do the walls. That way the walls drywall gives a little support to the ceiling drywall. After the ceiling then you do the upper wall with full sheets then the lower wall with sheets cut to fit with factory edges always joining another factory edge. That makes taping and mudding a lot easier.
> 
> The stringers in the walls are used to stop fire (if one were to occur) from spreading up the wall cavity. They are not necessary if the cavity is filled with mineral wool. 2x4 is standard for stud walls but you can use 2x3s on non supporting walls and even 2x2s on a basement wall like furring strips. Even with spacers in the walls they can still warp. A little bit of warp isn't going to hurt much. The drywall in place with screws will prevent some of that.
> 
> ...


Thanks, i will follow your recommendation, and there is much work to cut the insulation.
lglura


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## lglura (Aug 25, 2008)

Got the package with Green Glue yesterday, hope it's worth the price, it was very expensive:spend:


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## MatrixDweller (Jul 24, 2007)

lglura said:


> Thanks, i will follow your recommendation, and there is much work to cut the insulation.
> lglura


Best cutter is a long serrated blade (ie: Ginsu knife) or a fine toothed saw. 

Wear gloves a mask and a long sleeved shirt and maybe even goggles if putting cut pieces overhead. They say Rockwool is less itchy than fiberglass but I found it worse. I should have taped my sleeves over my gloves. I had to take a cool shower afterward to get rid of the itch.


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## rickp (Jan 14, 2008)

I found that our electric carving knife works great, I will never use a razor knife again!


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## lglura (Aug 25, 2008)

I use a big razor knife, it is clean edges when cut, but I need to replace the blade frequently.


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## lglura (Aug 25, 2008)

Drywalls finished and sealed off, the doors are mounted on both walls.
I've found to my disappointment that this is not a soundproof room, therefore, is the name of the thread misleading. The room is very much better than before, but not soundproof, low frequencies can still sound between floors.


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## lglura (Aug 25, 2008)

I find that Green Glue beginning to work, low-frequency noise from the floor above is more reduced for each day
:T:T:T


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## Ted White (May 4, 2009)

lgl, takes a few weeks to dry completely. It will get more and more dead wuth each day, as you're finding.


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## lglura (Aug 25, 2008)

Hi Ted. This is good, I hear the difference already after 3 days.


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## Ted White (May 4, 2009)

That's still early so if you're happy now, you'll be really happy later


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## chrapladm (Jun 17, 2009)

Anymore updates lgl?

And I was wondering if anyone can get the green glue? in other words can it be shipped world wide?

Thanks


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## lglura (Aug 25, 2008)

Here is new updates, walls are painted in colors S8000 and the roof is in the S7000. 
The floor is a vinyl coating. Now begins the exciting part of building the HT.


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## chrapladm (Jun 17, 2009)

Just curious how the progress is coming along?

Its been awhile so I hope all is well.


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## lglura (Aug 25, 2008)

Hi chrapladm, thanks for asking, it's been a while since I last visited the forum, has spent much time on building new speakers, here is a picture, I will give a description when I'm happy with the sound.


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## lglura (Aug 25, 2008)

Hi guys. I have been unlucky and got water damage in my basement. The floor in the cinema is damaged and needs replacement. Aaagh....the cinema was almost finished:hissyfit::crying:


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## tjambro (Jan 16, 2007)

So sorry to hear that! Is it just the floor and not any of the walls?


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## lglura (Aug 25, 2008)

The walls were fortunately not built on the floor, this was floating. Water damage was discovered so early that the walls are not damaged. I have good insurance and I have covered the damage, but it's sad because my HT should be done now. I'm going to make some changes in relation to what I had planned, I describe this with pictures when I'm ready. In the meantime, I keep on building my new speakers:bigsmile:


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## chrapladm (Jun 17, 2009)

Well I hope everything works out.....I was looking forward to seeing your finished pics


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## Ted White (May 4, 2009)

Wow. This is just sad. I don't think anyone could really appreciate how sad unless they built their theater themselves as you have. Makes me cringe (I built my own theater also)

Please keep us posted.


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## tjambro (Jan 16, 2007)

I think we all know how bad we would feel if this happened to us but it sounds like you are taking it pretty good. I'm glad your insurance will cover the damage and it sounds like your speaker building will keep you busy!

Soon after I finish my drywall (I'm mudding/sanding the soffits in both my theater and lobby) I will work on building a set of 7.1 speakers myself. I'm looking forward to it...actually I'm looking forward to anything other than drywall/soffit construction.


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## lglura (Aug 25, 2008)

I appreciate all the sympathy from you guys, i need it:sad:


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## lglura (Aug 25, 2008)

Finally I'm back again and I'm hungry to get the theater done, the front speakers are finished, the frame for the ATscreen is finished. Now it is to install cables and bass traps.


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## salvasol (Oct 31, 2006)

Nice!!! Good work :T


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## Ted White (May 4, 2009)

Really excellent work.
_Posted via Mobile Device_


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## lglura (Aug 25, 2008)

Hi, I have built complete five speakers and have two more before I am finished. Have mounted bass traps in corners and has tested a bit. It's getting really good. After the bass traps were installed, I had to turn down the volume to the bass. Looking forward to being finished with the speakers so that the measurement can begin.


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## brianhutchins (Apr 10, 2007)

Nice, it's good to see that water damage do hold you back too long.


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## lglura (Aug 25, 2008)

It is not long until I'm finished, waiting for parts for the movie screen. Here you see the bass trap to the rear wall, size 190x110x28 cm and consists of heavy insulation.


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## Ted White (May 4, 2009)

Your speakers look *fabulous*. I built mine also. I think more people should.

Did you follow a "recipe?"


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## lglura (Aug 25, 2008)

Hi Ted. It's good to be back after a long brake. I've built speakers that I have changed a bit. Increased volume and changed the crossover to match the level of treble. Has played for a while, and speakers sound better and better.


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## Ted White (May 4, 2009)

I always find it quite satisfying to recall building the speakers. I built them in the theater space before it was a theater. It was a small speaker factory for a while, building 7 channels and two 4' x 4' x 2' horn subs. 

\http://tedwhite.homestead.com/gallery3.html


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## lglura (Aug 25, 2008)

Agree, it's exciting and satisfying to build my own speakers, and the best part is that the quality will be good at a reasonable price. I have seen your speakers and they look extremely nice.


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## Ted White (May 4, 2009)

They sounds pretty dandy as well. Have you cranked youre up yet? I probably missed that part of your thread...


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## WilliamSmith (Aug 23, 2019)

wow, you are doing best things for soundproofing I m also queries about your techniques and ways.


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## WilliamSmith (Aug 23, 2019)

this your next steps?


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