lgl`s soundproof HT

[lglura]

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.

[salvasol]

I'll be waiting for those pictures...

[lglura]

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.

[lglura]

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.

[lglura]

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

[Ted White]

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

[lglura]

Ted White wrote:

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

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

[Ted White]

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

[lglura]

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

[Space]

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.

[Ted White]

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.

[Space]

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

[Ted White]

Space wrote:

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.

[Space]

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

[lglura]

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.
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.
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

[Space]

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

[Ted White]

Keep in mind you're still going to hear subs.
Posted via Mobile Device

[Seb]

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.

[paulspencer]

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.

[Ted White]

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.

[lglura]

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.

[lglura]

Ted White wrote:

Keep in mind you're still going to hear subs.
Posted via Mobile Device

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

[paulspencer]

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!

[Ted White]

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.

[Ted White]

lglura wrote:

I`ll build the room airtight with no leaks,

Tough, but you know that obviously

floating ceiling on floating walls

You mean independent ceiling joists as in the article? That's better than clips if you can do this.

... floating walls attached with resilient clips to the concrete

Clips on stone = 1 5/8" air cavity. That small air space with clips and drywall will improve your high frequency performance but your low frequency isolation will worsen. I have the data on that if anyone's interested. There are other issues with that air cavity and the resonance point of that stone wall, but that's another post

and a floating floor inside the wall.

This is for comfort? Getting the carpet and pad off the concrete?

I`ll have two airtight doors.

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