Wall construction and other Questions.

Hello, this is my first post. I am from Germany and my english is not good. So I hope you understand my questions..... :wink: My plan is to build a studio in an old big horse stable of an old farmer house. So I have enough space to built everything without a ceiling limit because the stable has an hight of 9 meters. So my idea is to make a floating floor (with wood framing or concrete) and built all my different rooms on these individual Floors without any conections to eachother. Now I have a few questions: 1. Building the walls. Which Version is the right way to go for: I think the first one, but i am not shure. You look from above on the wall. The Black is 3 layers of gypsum. The orange is the framing with insulations and the white is the air. 2. Can I built for each room a "little houses in house"? What i mean is: Is it a useable way to built the ceiling on the new walls? 3. When i built the ceiling on the new walls should i build it with the same system like the walls (like in point 2). 4. Which hight ist good for a) Control room b) Big Live Room c) Vocal booth & d) Drum Room. I don´t want the "perfect hight" I only want an idea of.... Many many question and a bad english. But I hope you can help me. Kindest regards Hendrik

Hendrik, Welcome to the site. If you haven't done so yet, read some of the sticky's at the top of the forum. The one on "complete section" has lots of good info on walls, etc. In your drawing, I would say the first one. Here's a diagram that shows the difference in STC ratings, etc just by placing the same materials in different locations of the construction.

Hi Aaronw, i have read a lot on this site. It´s a great Information pool. I know this "STR Picture" But the question is: Is the left site of this "STC 63 System" for 1 room and the right side on the other room, or have i need 2 of these "STR 63" Systems. One on the first room and one for the second room. Easier: Have I built 2 Frames or 4?... I think (hope..:-)) 2.....

Hi hendrik, Your left side of "STC 63" illustration is one room and the right side is the other room! So you only have to build one frame in one room and one frame for the other room. :) cheers

Hi Sen, thank you very much. I had already fear....:-) So, it would be very nice, if someone could answer my other questions. Thanks in advance. Best regards Hendrik

Hendrik, first of all welcome to the board; no apologies necessary here, your English is vastly better than my German (or any other language, for that matter) 1 - the other guys got this one - between any two places you want to block sound, you need two masses separated by air and insulation. Each mass can be multiple layers, as long as there is no air gap between layers. So your example of 3 layers of gypsum/insulation/air/insulation/3 layers of gypsum is fine - this should be your total construction between the air space in any two rooms you're isolating from each other, or from the outside world. 2 - Building your inner ceiling mass supported by the inner walls is a very good way to get isolation - ceilings, walls, floors, windows and doors ALL follow the same laws of physics as in question 1. 3 - Answered in #2 - 4 - Height is like money - more is always better. However, the WORST thing you can do for ANY room is to make any two dimensions the SAME - and a perfect cube is the worst of all. There are several accepted ratios for length/width/height that give better acoustic properties, only one of these is the ratio of 1:1.6:2.33 - an example would be a room that is 10 feet high by 16 feet wide by 23.3 feet long. There are several others - Also on this site is a basic room mode spreadsheet (Roomtune) I wrote over 20 years ago that can help pick ratios that work - a more advanced one was written by Jeff Szymanski, Head Acoustic Engineer for Auralex Acoustics - you can find it here - http://www.studiotips.com/tools Download ModesV2.xls - for both spreadsheets, you will need Excel on your computer. I can help with any questions you may have on these, just ask... Steve

Hi Steve, thanks a lot. Question 1-3 is answered and the important thing is: I understand it!...:-) But 2 more questions: A) Is a larger air space better? Or does the air space stands in relation to the STR level. B) It doesn´t matter which kind of room that is, when i use any "good" ratio? Is it right when i say "The more largely the room, the more highly the ceiling" (depends on the used ratio)? It would be nice, if you can answer my questions. Thanks in advance Hendrik

a - yes, larger space is better - I was going to ask whether you mean the space between wall panels or the space in the room, but realized the answer is the same. More space between wall panels (where the insulation goes) will improve isolation between rooms. More space within the room gives a more uniform sound field and a more natural sound. b - you're correct in your understanding of this. Also, as far as these ratios are concerned - for a smaller room, such as a vocal booth, it doesn't matter which dimension is which - the room can be taller than either of the other two dimensions, as long as the ratios are good. What you need is for no two dimensions of the room to be simple fractions of each other, like 1:3, 1:4, etc - The larger the room, the less acoustic problems you will have from these dimension ratios - this is because the further above the prime resonant modes of a room you get (in frequency of sound) the more closely spaced the resonances become, until they blend together and stop being noticeable as separate effects. What the larger room does is to "push" these separate resonances down in frequency until they are not audible. Hope that helps... Steve

Hi Steve, thanks a lot. I understand that and yes, I meant the air space between the wall panels. A further question concerning the Ratio thing. How do I calculates the room size, if the room does not have parallel walls? Should I use the maximum width, depth and height of the room? Thanks in advance Hendrik

For non-parallel surfaces, there is no easy way to be exact - you can get a pretty good idea by using the AVERAGE dimensions. So if your walls are 5 meters apart at one end and 5.5 meters apart at the other, you would use 5.25 meters. Sorry, but both the spreadsheets I linked to are in feet and inches; you'll need to convert metric values yourself... Steve

knightfly wrote:

For non-parallel surfaces, there is no easy way to be exact - you can get a pretty good idea by using the AVERAGE dimensions. So if your walls are 5 meters apart at one end and 5.5 meters apart at the other, you would use 5.25 meters.

Ok, thats fine.

knightfly wrote:

Sorry, but both the spreadsheets I linked to are in feet and inches; you'll need to convert metric values yourself... Steve

No Problem. I´ll try to built a studio. If that is too heavy, I should give up...:-) Can I ask you, if I have further questions in the planning phase? Thanks in advance. Hendrik

Absolutely, that's why we're here... Steve

My first picture test...:-)

No problem, Hendrik - however, I couldn't get your image to work - can you try again? Thanks... Steve

Hi Steve, Ok, something gone wrong. Here is the picture now. and here are the questions again. Question1: How much degree should I angel the side walls of my control Room? I mean the brightly blue ones. I heard about 6 degree, but this is not really working in a 5.1 setup. Question2: How much degree should I angel the ceiling? In the front (where the 3 front speakers are) the ceiling hight should be lower, right? and in the back (where the sofa is) the ceiling should be higher, also right? But how much degree is a good startind point. Question3: I have a entrance Problem for the control room. Is it possible to make the door in the back where the sofa is? Or can I make the entrance in the side walls between the rear wall and the rear speakers? I don´t want an entrance through one of the recording rooms.... Finally this is a basic plan. The recording rooms are not optimized. Please only help me with my Control room. I will design the recording rooms later. Thanks in advance. Regards Hendrik

Your CR needs to NOT have the mix position dead center front-to-back - more like I shifted it in a markup of your plan, only with the rear surrounds moved forward too, and the front left and right's pulled in and re-angled to maintain equilateral triangle - either that, or you need to make the room deeper - you do NOT want your head sitting centered front/rear, as it is already centered left/right for proper stereo - this would put you in two dead center null points in the room, with peaks as well. Angles for sidewalls - 6 degrees will only take care of flutter echo. For RFZ, you need more. ONly by doing the geometry of the room and "ray tracing" from each speaker to walls and back, can you find out the correct angles. By showing this as a surround room, you probably won't be able to do RFZ at all, unless you use absorption where a stereo room would normally use hard surfaces. You do show your speakers at correct distances, they should all be within an inch or less the same distance from your head. Sorry, but it's after 3 am here and I have to go fight insurance companies tomorrow - will try to add more soon... Steve PS – didn't get this posted last nite, ISP was screwing around with maintenance and kept losing my connection -

Hi Steve,

knightfly wrote:

Your CR needs to NOT have the mix position dead center front-to-back - more like I shifted it in a markup of your plan, only with the rear surrounds moved forward too, and the front left and right's pulled in and re-angled to maintain equilateral triangle - either that, or you need to make the room deeper - you do NOT want your head sitting centered front/rear, as it is already centered left/right for proper stereo - this would put you in two dead center null points in the room, with peaks as well.

I did not understand that. Can you explain that in simpler words? The Symetrie is with + - 30 degrees and +-110 degrees fixed, how the 110 degrees are a little flexible and the distance to the mix position should be the same, or not? But probably I did not understood this paragraph...:-)

knightfly wrote:

Angles for sidewalls - 6 degrees will only take care of flutter echo. For RFZ, you need more. ONly by doing the geometry of the room and "ray tracing" from each speaker to walls and back, can you find out the correct angles. By showing this as a surround room, you probably won't be able to do RFZ at all, unless you use absorption where a stereo room would normally use hard surfaces.

But is there an useful acoustic optimization between "Stereo CR" and "Surround CR"? I want to mix both. Normal Stereo mixes and also Movie surround mixes...

knightfly wrote:

Sorry, but it's after 3 am here and I have to go fight insurance companies tomorrow - will try to add more soon... Steve

Good luck! I know what that means....:-) Regards Hendrik

But is there an useful acoustic optimization between "Stereo CR" and "Surround CR"? I want to mix both. Normal Stereo mixes and also Movie surround mixes...

There are recommendations. Sorry, it is english and very large, but about the most comprehensive document I know of detailing the differences in mixing and acoustics for different environments is http://www.naras.org/pe_wing/5_1_Rec.pdf You can probably useful information in german for classicl and tv mixing in EBU documents. The T3276 and t3286 series of come to mind. I seem to remember the url is: http://ebu.ch Good luck! edit: put some words into english and corrected the EBU url.

Hello, thanx for the link. Is it true, that NOT all Speakers should "show" to the mix position? In this 5.1 rec PDF I read, that the front LR Monitors should show 1 feet behind the Mix position and the rear LR should show 1 feet in front the Mix position. Why? Regards Hendrik

Is it true, that NOT all Speakers should "show" to the mix position? In this 5.1 rec PDF I read, that the front LR Monitors should show 1 feet behind the Mix position and the rear LR should show 1 feet in front the Mix position. Why?

It is difficult to answer your question. If you post a link or at least title so that we can read the document, we can answer your question much better. For starters, read the EBU t3276 abd t3276-s1 documents. I am certain you can get those in german off the EBU website (I corrected teh url in my previous post).

Sorry, damned ISP was screwing up so bad when I posted that I forgot the pic - Are you familiar with room modes, nodes and anti-nodes? These are the problems I was referring to when talking about NOT putting your head exactly centered between front and rear walls, nor centered between floor and ceiling - by definition, your head must be centered left to right or you can't get a balanced stereo sound field. However, if you center your head in the other two dimensions, you will get huge peaks and nulls in the sound level at different harmonics of your room dimensions. This makes it nearly impossible to make valid decisions about a mix or to do a mix that will translate to other systems or other rooms. The 5.1 pdf completely ignores room construction or acoustics as near as I can see - In my next CR, I'm considering setting up for both stereo and 5.1 by making reversible inserts for the areas around the front of the CR, one side being reflective for RFZ stereo mixing and the other side being absorptive for 5.1 mixing - The reason for this is that when you add rear surround speakers and a center channel speaker, you get new reflection paths that weren't there before - this makes it nearly impossible to get away from early reflections at the mix position which are caused by these extra speakers firing toward surfaces that previously did not have sound sources directed at them - the only way I've seen considered that solves this problem is to absorb these surfaces; specifically, the front hemisphere of the CR. Not having tried it, I'm not sure you couldn't use a 5.1 CR with absorbed front hemisphere for also mixing in stereo, as long as you perhaps made other parts of the CR more "live" to compensate for the deader sound - what the "founding fathers" of surround generally recommend for 5.1 mixing is to make the room quite dead, and then add the lost ambience back to the mix digitally. This is not something I think I'd like for stereo mixing, but I'm not yet at a point where I can say for sure. That won't happen until I get my new facility designed and built, which will probably take a few years yet. Anyway, I marked up your CR drawing and put the desk more where it would need to be if you don't make the room itself deeper front to back - otherwise, you will be sitting in a very uneven sound field. Naturally, you would also have to relocate the center channel speaker to maintain equal distance to your head - also, the surrounds may have to move forward as well (although there is a fairly wide range of acceptable angles for the rear surrounds) Did that help any, or am I still talking in circles? Steve

Steve:

The 5.1 pdf completely ignores room construction or acoustics as near as I can see -

If you are referring tot he grammy document you are correct that it ignores construction. As far acoustics goes, it defines what the results should be, without getting into at all into HOW to achieve it. what prompted my posting it was Hendrik's question about speaker placement and stereo/surround compatibility and music /movie style mixing. It (the grammy document) includes what the "founding fathers" of surround generally recommend for 5.1 mixing is to make the room quite dead, and then add the lost ambience back to the mix digitally. This is not something I think I'd like for stereo mixingtatements almost identical to your

what the "founding fathers" of surround generally recommend for 5.1 mixing is to make the room quite dead, and then add the lost ambience back to the mix digitally. This is not something I think I'd like for stereo mixing

and going even further noting that depending on the market being mixed for that surrounds may used for ambiance or localization. Hendrik: I hope I didn't overload you with information, but the questions you asking were getting into the underlying theories and concepts of room designs. With it being your room and your money, I felt that you should have the choice to study and understand these if you choose to.

Hi AVare,

AVare wrote:

It is difficult to answer your question. If you post a link or at least title so that we can read the document, we can answer your question much better.

I mean your "Recommendations For Surround Sound Production" linked document...:-) The 5.1rec.pdf!!! I readed it there... When you follow this, you have´nt a exact sweet point... Why?

AVare wrote:

I hope I didn't overload you with information, but the questions you asking were getting into the underlying theories and concepts of room designs. With it being your room and your money, I felt that you should have the choice to study and understand these if you choose to.

No, please tell me what you know! I am learning!... Hi Steve,

knightfly wrote:

Are you familiar with room modes, nodes and anti-nodes? These are the problems I was referring to when talking about NOT putting your head exactly centered between front and rear walls, nor centered between floor and ceiling - by definition, your head must be centered left to right or you can't get a balanced stereo sound field. However, if you center your head in the other two dimensions, you will get huge peaks and nulls in the sound level at different harmonics of your room dimensions. This makes it nearly impossible to make valid decisions about a mix or to do a mix that will translate to other systems or other rooms.

Now i understand what you mean! I know that, but i have´nt remember it. Thanx that you tell me again. I will update my CR design....

knightfly wrote:

The reason for this is that when you add rear surround speakers and a center channel speaker, you get new reflection paths that weren't there before - this makes it nearly impossible to get away from early reflections at the mix position which are caused by these extra speakers firing toward surfaces that previously did not have sound sources directed at them - the only way I've seen considered that solves this problem is to absorb these surfaces; specifically, the front hemisphere of the CR.

I understand, but it must be possible to make flexible Acoustic Systems, or not? Then I can design a "normal" Stereo CR and with putting some Absorber on, I have a 5.1. Ok it´s sounds to easy, but will it work? Regards Hendrik P.S. I will update my plan tomorrow. We will see...:-)

I mean your "Recommendations For Surround Sound Production" linked document... The 5.1rec.pdf!!! I readed it there... When you follow this, you have´nt a exact sweet point... Why?

Okay, I went back to both your original post on this point and the 5.1 document. understand now. By "show" you mean aimed at. The idea of a sweet spot is theoretical. If in reality there was just one specific sweet spot, then you wouldn't even move your head! The idea of aiming the speakers behind the main listening position is to increase the area where good imaging will occurr. I hope this helps!