Building a new studio please help

Dear Mr.Sayers and everybody that can and wants to help, My name is Aleksandar and I am from Skopje, Macedonia. I saw two projects that you helped to build in Macedonia so I would like if you have some time to see my ideas and to tell me if something is wrong with it. So I am building small 3 room studio in an audio and video studio that is mainly occupied with film and video projects. I am planning to build one 5.1 surround room, one stereo room and one vocal booth. The dimensions of the rooms are predefined so I cannot change it. I have some kind of an idea for the surround room and still thinking about vocal both and the stereo room as they are really very small. After building room in a room eggshell in 5.1 room I am also planning to put hanging absorption panel(cloud), with additional acoustic hangers above it, over the mixing position and the console above for further absorbing the low frequencies. In the back wall corners I am planning to build super chunks and some kind of diffusion on the back wall. The speakers are for the 5.1 room are Genelec 8240A with subwoofer 7270Aand for the stereo room Genelec 8030Aand all are going to be freestanding. I am posting the corel draw .cdr adobe photoshop .psd and a adobe acrobat .pdf file so you can get a general idea about what I am talking about. Any suggestions and remarks about the plans are more than welcome. Thanks in advance, Aleksandar :D

I have posted twice with layout & a design they want you to use some Sketchup program to make your design..seem they cant look at a design in any other form...ummmm I have seeked help else where & more professional. good luck....

Tony - if you had read the "BEFORE YOU POST READ THIS" thread you may of got some help.

Aleksandar - which room did you post the plan of - the stereo or 5:1 room?

trayj57 wrote:

I have posted twice with layout & a design they want you to use some Sketchup program to make your design..seem they cant look at a design in any other form...ummmm I have seeked help else where & more professional. good luck....

If I had ta throw a rock at it, the reason Sketchup is choosen is because it is available Free of charge and is available to Everyone via Google. Now unless you have developed your own high profile search engine that you can get a higher rate of exposure across the 'net with, maybe it is one of those times to keep the mouth closed and the mind open:) It does work wonders on the uneducated, Brien

i don't think there is a problem with other tools - visio, paint, etc. its more often that the information is incomplete. instead of focusing on providing detailed measurements and including the information on obstructions, doors, windows, etc... along with some details outlined in the read me before posting, people often leave out while sets of dimensions or key information. it can make it very difficult to effectively provide an answer without guessing too much.

Thank you all for your reply. I use mainly Corel Draw for my plans but I downloaded sketchup trial version now and I am trying to figure it out how is it working.The .pdf files I am attaching are just export files form Corel Draw. A friend of mine tried to make the rooms in 3D studio Max but it just don't look like yours sketchup drawings. Since I am only a audio engineer I am really bad drawing things :-) Let me explain something about the building. This building used to be military tanks repair garage. It has ground floor and 1st floor. So the construction is rigid and huge. Whole building is 2500 m2. The audio rooms are on the first floor. Other part of the building will be used as video and film post production facility, 1 big film studio and 2 smaller TV studios. The outer walls of the audio rooms are filled bricks with both sides covered by cement and are 20cm thick. The floor is 20cm thick concrete and holds up to 750kg/m2 load and the celling is concrete 12cm thick that holds 250 kg/m2. Above the celling there is empty space around 2m high to the roof that is made of concrete and insulation and metal panels above. Because I couldn't found any spring isolators Concrete Floating Floor System or Kinetics Noise RIM floating floor system in Macedonia I decided not to float my floor. I just decided to use a local common practice to make an 5cm concrete floor over highly compressed 1cm stiropor (expanded polistiren-EPS) board. That I hope will help me with impact noise. I glued 1cm thick wood over it. Separate armored channels for the audio, network and power wires are put in to the concrete floor. The inner walls are planed to be build over the new floor with metal gypsum frames separated 2.5cm from the existing walls, 10cm Isover glass wool and 2 layers of 12,5mm Knauf gypsum boards. After I build the inner walls and place the windows and doors I am planing to measure the acoustic parameters of the room. And than to try to acousticaly tweak it as need it. The first drawing I attached in my firs post was the 5.1 room here I will attach the stereo room too. In between the stereo and the 5.1 room there is a vocal booth. I am interested how to build the hangers in the front corners. Should I do some mathematics or calculations or to put as much hangers I can fit in to available compartments. How big should be the opening in the lower part of the corner wall of the hangers compartment. And should I consider putting hangers above the hanging cloud above the mixing position or not. I found this M300SEL booth.skp(attached below) of vocal booth design on this forum. Is this good one and can I use it? Thank you all very much :D

your 2d drawings are very good. i'll leave it to others to determine if the mosel booth is ok or not but it may be... ;-) the hangers generally should be varied in size and hanging position. the hangers work on diffraction and are about 1/7 of the intended frequency wavelength - hanger + distance from hanging surface (ref. Jeff Cooper). spacing is also somewhat key so 8-12" (20-30cm) is a good spacing for larger hangers. http://www.amazon.com/Building-Recordin ... 0916899004

Thank you very much for your reply Mr. Gullfo, Isn't Jeff Cooper the one that designed George Lucas Skywalker Sound? Unfortunately I can't order from amazon from Macedonia but will ask some of my friends to bring the book for me from US. I read also "Master Handbook of acoustics" by Mr. F. Alton Everest, "Home Recording Studio: Build it Like the Pros" by Rod Gervais, "Sound Studio construction on a budget" by Mr. F. Alton Everest. I am still trying to learn sketch up for more detailed drawings :D Best Regards, Aleksandar :)

Dear Mr. Gullfo, I would like to ask you something about your reply. Quote: "the hangers generally should be varied in size and hanging position. the hangers work on diffraction and are about 1/7 of the intended frequency wavelength - hanger + distance from hanging surface (ref. Jeff Cooper). spacing is also somewhat key so 8-12" (20-30cm) is a good spacing for larger hangers." Speaking of hangers I intend to build in the front corners the rooms. Please look at he picture that I attached bellow and tell me, what you have said , did you mean something like this? And speaking of hangers positions should they be all parallel like in picture in the attachment or there is better placement like fish bones or somehow else? Thank You very much, Aleksandar :D

sorry - my fault - i shouldn't discuss math and use dashes to break up sentences.... :oops: assume a hung trap constructed of free-hanging fiberglass-covered panels, each measuring 24" long (l), on 6" hangers (s) (total length = 30" or 2.5 feet) would be effective above 2.5' x 7 = 17.5' Effective cutoff wavelength 2.5 x 7 = 17.5 ft. Frequency = V/l = 1130/17.5 = 64.5 Hz so you have f = 1130/(7 * (l + s)) but you need some minimums for hanging distance and inter-panel gaps. you can adjust the heights of the hanging panels as well as the panel size. you want the panels to be mostly perpendicular to the sound entry which for a corner trap is forward and back, not at a 45 degree. the cavity of the hanging traps is lined with insulation (peak pressure) and usually a layer in front (peak velocity) as a function of the 1/4 wavelength depth of the cavity. also, the width of the panel must play some role in efficiency but i'm not sure its easily calculated. ultimately what you want to achieve is sound going in and not coming out :-)

Thank You very much Mr. Gullfo for explaining the hangers principle in details. and the picture is great. :P So let me see if I got this right. If I have l=2,5m long hangers and s=20cm to the hanging surface, as shown on the picture attached below, the frequency will be f = 344/(7 * (l + s)) f=344/7*2,7=18.2Hz. Should I put the insulation in front of the hangers just behind the cloth face? It is very difficult to find an appropriate cloth here in Macedonia so I read somewhere on this forum that any cloth you can blow through is probably good enough. Is this true? I have another question, now about slat helmholtz absorbers. My constructor engineer suggested that maybe I should use 12.5mm gypsum board instead of wood because we have a lot of left in stock, and it is easier to cut the gaps between slats.I have attached just a preview as I imagine how to do it. Anyway the boxes behind the Slats are planned to be made of gypsum board as a part of the inner shell construction. I planned to build the slat helmholtz absorbers on the both sides of the mixing position starting just after the hangers box in the corners and in front wall below and above the window to the vocal both. Thank you very much again. Best Regards, Aleksandar :D

Joka wrote:

the frequency will be ... 18.2Hz. Should I put the insulation in front of the hangers just behind the cloth face?

the estimate of 18hz is right based on theory but in practice i'm not certain you will get that solely on the hanger size as the cavity in which it sits plays a role. you should probably target something around 45-50hz as reasonable for the corner trap (unless you can build it about 1,5m deep or so). a panel trap may be more likely to help you with the lower problem frequencies (which you can determine approximately from room mode calculations). yes to the insulation behind the cloth.

Joka wrote:

It is very difficult to find an appropriate cloth here in Macedonia so I read somewhere on this forum that any cloth you can blow through is probably good enough. Is this true?

yes and remember to treat the cloth with a fire retardent agent for safety.

Joka wrote:

slat helmholtz absorbers. My constructor engineer suggested that maybe I should use 12.5mm gypsum board instead of wood because we have a lot of left in stock, and it is easier to cut the gaps between slats.I have attached just a preview as I imagine how to do it.

you could use gypsum but it can get messy - flaking, etc. wood is generally a nicer finish. there is a helmholtz calculator on this site you can use to compute the proper sizes.

Thank You very much Mr.Gullfo, I will start building the rooms and will post some pictures so you can see how it is going. Best Regards and thanks again, Aleksandar :D