Need some advise for new design.

The room "modes" are basically resonant frequencies at which the room itself vibrates, simply due to the dimensions of the room. If you play a note on an instrument, and the sound wave for that note fits exactly between two parallel walls, then that will cause a "standing wave" in the room. Basically, the sound sort of "bounces back and forth" between the walls perfectly at that exact frequency, but not at other frequencies. So that specific frequency is a "mode" for that specific room dimension. For example, if you have two walls facing each other exactly 4.2 meters apart (about 13' 9"), then any time you play a note that has a frequency of 82 Hz (a low "E" on your keyboard or bass guitar), that "mode" of the room will vibrate in sympathy with the note. The "mode" can be said to actually store some of the sound energy from that note, then it will release the energy back into the room even after you stop playing the note: in other words, the room itself will continue to vibrate at that frequency for a certain amount of time. That is a "mode". (Its actually a bit more complex than that, but it gives you a rough idea). Since the modes depend on the dimensions of the room, and since they also occur at twice the frequency, three times the frequency, 4 time, 5 times, 6 times, etc... for all of the harmonics of that note, all they way up the scale...., so obviously there are going to be a LOT of modes in a room. And those are just the simple "axial" modes that occur between two parallel walls. There are other kinds of modes that bounce around between any four walls of the room, and yet other modes that bounce around between all six walls (the ceiling and floor are also considered to be "walls" here). So you are going to have lots of modes in your room. OK, so obviously modes are not nice: they can make you hear some sounds too loud in your mix, since the room is adding its own resonance to some notes and not others. They also add a sort of "reverb" to some notes and not to others. Not good. It would be nice if there were some way to get rid of the modes in the room, but that simply is not possible: Modes are a direct consequence of having walls around your room. The only way to have no modes, is to have no walls! So you cannot eliminate the modes. But what you CAN do is to make sure that the modes are spread around evenly, across the spectrum. In other words, you want to make sure there are no large "gaps" where there are no modes at all, and you also want to make sure that you don't have several modes all piled up at the exact same frequency, or very close frequencies. You want to spread the modes around evenly. You do that by carefully choosing a "room ratio", which is basically just what it sounds like: It is the relationship between the dimensions of the room (length, width, height). You do NOT want any two of those to be the same, nor to be multiples of each other. So if your room is 2.5 m high, then you must make sure that it is not also 2.5m wide and 5 m long! If it were, then you'd have dozens of modes all piled up 34 Hz, 68 Hz, 136 Hz, etc., with huge empty gaps in between. That would be really bad. So the idea is to choose dimensions for your room that gives you an even spread of modes. What is important here is not so much the dimensions themselves, as the relationship or ratio between those dimensions. So you need a good ratio. Fortunately, several scientists have already figured out a bunch of good and bad ratios. You don't need to do figure that out all over again: they already did it, and wrote books about it. So you just need to choose one of those known good ratios that happens to be close to the dimensions of the space that you have available for your room, and then you adjust the location of the walls that you are going to build, in order to get as close as you can to a good ratio. The other thing you can do is to then treat the room with various kinds of acoustic "things" (such as absorbers, resonators and diffusers) in order to control the modes a bit, so that they don't have such a bad effect on the room. You can't actually kill the modes, but you can sort of "beat them into submission" a bit with good treatment. So your room needs to start out with a good ratio to have a good modal spread, and then it needs to have suitable treatment, to squash the modes a bit. That's all there is to it! That's what modes and ratios are all about, basically. - Stuart -

Soundman, Thanks for all that info.. I need to figure this is out. I will keep you guys updated as we should begin the room framing this upcoming week. Quick question to anyone. We plan on doing drums in our live room. Do you think that would be a good size(not to fit the drums) but that would give good results in the future.. Thanks for all your help guys..

Well guys as of right now we are in the framing stage right now. Following Gullfo framing guide, everything thing is coming out great. We did change the layout some bit of the room like closing the rear enterance in the control room. We are leaving the iso booth/control room/live room design, but the acoustic layout will be different. just one quick question. When we come to the ceiling we are doing the wood framing, stuffing it with insulation and 2 panels of sheet rock. On the other side (facing the warehouse) do we leave it open that you see all of the insulation, or do we cover it with sheet rock/plywood? and one last question. i know that we are supposed to finish the rooms with sheetrock on the frames.. how come some studio finish them with just the frame and fabric.. no sheetrock what so ever. We wanted to use this type of treatment, but in our case is it possible or not. Thanks for all your time guys!! Your the best :yahoo: :yahoo: :yahoo:

Sounds like something similar to John's "inside out wall" may be what you saw. Or they could have designed and built all the interior treatments to very meticulous specifications so it just looks like they always existed.

For my place.. do you recommend that "inside out wall" design or should i stick to the sheetrock and acoustic panels mounted or any other recommendation?? thanks

We did change the layout some bit of the room

Careful with changing stuff! Glenn does things for a reason. It might or might not be OK to change things. You should post your proposed changes here first, to check if what you are planning is OK or not...

but the acoustic layout will be different.

What acoustic treatment? Glenn's plans don't show any acoustic treatment yet! We didn't get to the point of designing that for you, but you seem to be BUILDING stuff already? :shock: All that Glenn designed here is your basic isolation shells, nothing more. The acoustic treatment still needs to be designed...

On the other side (facing the warehouse) do we leave it open that you see all of the insulation, or do we cover it with sheet rock/plywood?

Are you building "inside out" or normal? Maybe you should show what you are doing in SketchUp, or with photos. The answer to your question is: it all depends. If you add sheetrock in the wrong place you could create a 3-leaf system, which would totally trash your isolation. If you don't add sheetrock where you are supposed to then you'd only have one leaf, which would also trash your isolation. Better show us what you have and what you are planning, then we can answer.

i know that we are supposed to finish the rooms with sheetrock on the frames..

Correct. The sheetrock can go EITHER on the inside of the the studs (room side) OR on the outside of the studs (wall cavity side). But NOT both.

how come some studio finish them with just the frame and fabric.. no sheetrock what so ever.

There is ALWAYS sheetrock (or some other form of mass). If not, then you don't have any isolation. It's that simple. In order to isolate, thre has to be mass. So what you are seeing in those "other studios" is either inside-out walls (like Brien said) or you are looking at the frames that have the acoustic TREATMENT on them, not the frames that have the ISOLATION on them. It can be two different things. Or you can combine it into one. Provided that you design it carefully, plan it carefully, and think it through BEFORE you start building frames... You can so the same for your room: you can either build inside-out and use the same frame for both isolation and some of the treatment. Or you can build separate frames for isolation and treatment. They are two different things, and you haven't shown us your design for the treatment yet (only for the isolation), so its hard to say what you can and cannot do, without first seeing your design. Maybe you should just post your entire SketchUp model here, so folks can have a look at it and see if you are getting things right. It sounds to me like there might be some issues with what you are planning. Post your model and we'll look at it. Also post some photos of the space, and what you have done so far. - Stuart -

Soundman2020 wrote:

We did change the layout some bit of the room

Careful with changing stuff! Glenn does things for a reason. It might or might not be OK to change things. You should post your proposed changes here first, to check if what you are planning is OK or not...

but the acoustic layout will be different.

What acoustic treatment? Glenn's plans don't show any acoustic treatment yet! We didn't get to the point of designing that for you, but you seem to be BUILDING stuff already? :shock: All that Glenn designed here is your basic isolation shells, nothing more. The acoustic treatment still needs to be designed...

On the other side (facing the warehouse) do we leave it open that you see all of the insulation, or do we cover it with sheet rock/plywood?

Are you building "inside out" or normal? Maybe you should show what you are doing in SketchUp, or with photos. The answer to your question is: it all depends. If you add sheetrock in the wrong place you could create a 3-leaf system, which would totally trash your isolation. If you don't add sheetrock where you are supposed to then you'd only have one leaf, which would also trash your isolation. Better show us what you have and what you are planning, then we can answer.

i know that we are supposed to finish the rooms with sheetrock on the frames..

Correct. The sheetrock can go EITHER on the inside of the the studs (room side) OR on the outside of the studs (wall cavity side). But NOT both.

how come some studio finish them with just the frame and fabric.. no sheetrock what so ever.

There is ALWAYS sheetrock (or some other form of mass). If not, then you don't have any isolation. It's that simple. In order to isolate, thre has to be mass. So what you are seeing in those "other studios" is either inside-out walls (like Brien said) or you are looking at the frames that have the acoustic TREATMENT on them, not the frames that have the ISOLATION on them. It can be two different things. Or you can combine it into one. Provided that you design it carefully, plan it carefully, and think it through BEFORE you start building frames... You can so the same for your room: you can either build inside-out and use the same frame for both isolation and some of the treatment. Or you can build separate frames for isolation and treatment. They are two different things, and you haven't shown us your design for the treatment yet (only for the isolation), so its hard to say what you can and cannot do, without first seeing your design. Maybe you should just post your entire SketchUp model here, so folks can have a look at it and see if you are getting things right. It sounds to me like there might be some issues with what you are planning. Post your model and we'll look at it. Also post some photos of the space, and what you have done so far. - Stuart -

thanks stuart for you quick response. all we changed in the room is the rear enterance of the control room. it was going to be a bit unconfortable for the room layout it self and kind of an odd place for the door into the room. (sorry glenn for the change) I know that we dont have an treatment design yet.. it was just me thinking ahead within some spare time.. Right now we have the wood framing (need to stuff it with insulation and cover with sheet rock) isolated from the floor (carpet underneath, had no other choice//we have to keep it that way due to the landlord) the thing with the ceiling, we have a wood frame with insulation and sheetrock (room side) but dont know what to do with the ceiling (warehouse/open side) if we should just leave it open, or add wood/sheetrock.. im guessing its better to leave it open towards the warehouse ceiling a few feet on top. with the room finishes we will go with sheetrock on the walls (room side) but when the treatment stage comes along we were planning doing some of the inulation/fabric walls in the rooms for some better absorption/treatment.. im going to try to get a sketch of what we have done so far, we dont have any treatment design yet.. hoping to getting some help on that.. but as of right now we are on the suggested stage of framing like the one gullfo.. and i will try to get some pics in soon too.. i dont have a complete model of the place. cause i dont know if the designs would be any good, im using the suggestions here. Thanks to everyone for your help and time.

it should be no problem on the door change. obviously you need to make it work. i'd cap each of the rooms with a ceiling of drywall to create fully isolated rooms. otherwise you're just flanking between rooms overhead.

So drywall on the top side of the ceiling is a good idea.. then thats how it would be Thanks guys..

sorry, maybe i misunderstood, you putting drywall on the ceiling inside? if so, the you could leave it open on top. i thought you meant you were leaving the ceiling open to the space above the rooms...

i thought you meant you were leaving the ceiling open to the space above the rooms...

That's what I understood too! Photos.... photos.... plans.... SketchUp.... - Stuart -

Yeah i noticed. how its going to be (from the inside of the room is) 2 panels of drywall//wood frame//with insulation in between.. and then leave it open.. nothing on top.. even if I have a few feet of space on top?? Thanks

What is above those "few feet of space"? And what is around the rest of the room (the outer leaf of the side walls)? How is that built? Also, how much isolation do you need? I looked through your thread briefly but didn't see it anywhere: What is your target number for isolation? Everything matters. You most likely cannot just leave it open like that, and will need to do "something" with drywall, but exactly "WHAT" you should do depends on what you have right now, and what you are planning to do. Once again, photos or an accurate SketchUp model would be great. Without that, we are all just wandering around in the dark... - Stuart -

Ill try to get an Sketchup to you ASAP Isolation = there is another recording studio next door, which always decide to blast their mains for anything and we need some isolation against that. I will try to get a sketch up to you guys soon thanks

Morning guys. Sorry for my bad sketchup skills Ive attached a rough sketch of the stage we are now (did it fast cause im at work, and sketchup wont download at home) I dont have the exact room measurements at the time, when we finish the framing/drywall, I will re-measure everything for more detail. and will have pictures soon too.. Right now we are in the framing stage of the rooms as suggested by Gullfo. Just the standard 2x4 framing with the insulation stuffing, and 2 layers of drywall (not in this step yet) Soundman, the space on top of the rooms is 6 ft. The thing is that next door we have another recording studio and their bass is way too much. That was the question in regards with the ceiling and the drywall on top of it to kind of close it out. Ive researched, and everything says just to do for the ceiling the 2x4 framing, with insulation and 2 layers of drywall (towards inside of room) leaving the top (unseen side) open to the space above. For the ceiling (for more detail) we are doing a 2x4 framing (from enterance wall to window wall in iso booth//window wall to back wall in live room) which is going to be filled with insulation and finished with 2 layers of drywall (room side) Only problem we have in this place is the wall that is in between the iso booth and the control room (wall with window path) This wall can not be moved/replaced/taken down..nothing :x . Its the original construction and the landlord was nothing to be moved. What we planned to do was take of the sheetrock in the iso booth side and fill it with a bit of insulation. (do you recommend this, or leave it how it is?) The sheetrock panel on the control room side has to stay (no exceptions) With this wall we were going to do the framing with the window opening and build a 3-leaf system, just on this wall alone (have no other choice, open to ideas) We are building on top of carpet flooring (landlord again!!) which we are going to seal everything with caulk/sealent, and soon have wood flooring. I know that we are way to advanced for the treatment stage, but I have attached a picture of a sketch i found here, that has more or less the design (if possible) that we want for our room. We were looking into doing the front and back walls of the control room like this and then passed the windows putting up treatment panels (DIY) And in the iso/live room at least do one of those completly treated walls (like in the picture) to have a bit of extra treatment. thanks for all your help. ask anything and i will respond ASAP

You want to do something different than what this suggests. Framing on one side, but not both. download/file.php?id=35416&mode=view

xSpace wrote:

You want to do something different than what this suggests. Framing on one side, but not both. download/file.php?id=35416&mode=view

Thanks xSpace for your reply.. I dont understand your question.. I dont want to change anything on the framing.. What I wanted to change was the idea in the room treatment such as instead of using panels mounted on the drywall (prefabricated panels from ATS, GIK and such) to having a few panels and have a "wall acoustic panel" or dont know what to call it. Something that the whole wall will be the panels (such as the inside out wall, with out the drywall and the studs.. dont know if you understand me) I dont know if what we are doing in the place of the wall dividing the iso booth and the control room that can not be taken down or moved.. its kind of a 3-leaf design or something like that.. dont know if this is right.. Thanks everyone

if you look at this detail posted earlier, the center wall and isobooth wall are isolation walls, and the center wall has an opening for the window. the window itself sits on a small set of isolation framing extended into the control room to complete the walls from the center. the rest of the framing are treatment walls. there is no 3rd wall with drywall on it (or shouldn't be). download/file.php?id=34924&mode=view in the case where you're leaving this flat, then the window would be in the center wall as shown in your diagram. otherwise you need to strip the drywall off that center wall to avoid a third leaf.

What is that "middle" wall made of? How is it built? If it is something massive like brick or concrete, then it won't do any harm, I reckon. But if it is an ordinary "drywall on studs" wall, then it WILL be a problem. If that's the case, then like Glenn said, just take the drywall off the frame before you build the other two walls. The frame can stay there, if you want, but the drywall has to go. - Stuart -

Thanks guys for you help Yeah the middle wall is an ordinary wall with drywall and metal studs, we did strip down the sheet rock in the iso booth side, and were planning on stuffing it with more insulation ( we will need to talk to the owner to see if we can strip down the drywall in the control room side too.. Im trying to understand this to my best ability, the wall that is there now.. we can use that as a isolation wall.. so in the control room we would only need to build 3 walls.. the front/back walls and the one off to the right with the window for the live room.. Ive attached a detail of my confusion using the sketch of gullfo.. EDIT: Now I understand about "the wall" so we just leave the frame there.. no drywall at all and then we can just build our framed wall infront of that.. so it would be like.. || ISO BOOTH || WALL || CONTROL ROOM ||

Yup: Going from the "iso-booth" side through to the "control room" side, it would be like this: - 2 layers of 5/8" drywall - studs (new) - air - studs (from the existing wall) - air - studs (new) - 2 layers of 5/8" drywall Or if you are going to build inside-out, then it would be: - studs (new) - 2 layers of 5/8" drywall - air - studs (from the existing wall) - air - 2 layers of 5/8" drywall - studs (new) And of course, you'll have some insulation in there somewhere, too. But the basic idea is that you want ONLY two leaves in there, and a large air space between them. Each leaf is made from one for more layers of drywall, but you do not want more than two leaves. - Stuart -

Soundman Thanks man for your help Now i get the idea.. Now I have 2 question.. What would be the situation if we can not remove the drywall on the control room side from that pre-existing wall? and if we are allowed to take it down.. Do we need to take down all the drywall from the complete wall (around the door framing too) or just in that section where the iso booth and control room are next to each other (iso booth is not the same length as the control room) Once again, Thanks to everyone for their help..

Ensonix Studios wrote:

Thanks xSpace for your reply.. I dont understand your question..

Forgive me, I jumped in where I didn't have a complete grasp on the environment :) A lot like my first marriage!

xSpace wrote:

Ensonix Studios wrote:

Thanks xSpace for your reply.. I dont understand your question..

Forgive me, I jumped in where I didn't have a complete grasp on the environment :) A lot like my first marriage!

Dont worry about it dude.. Just have alot of confusion.. but im getting it now.. thanks to all of you guys help..

Now I have 2 question.. What would be the situation if we can not remove the drywall on the control room side from that pre-existing wall?

That would be bad: That would leave you with little choice but to build a 3-leaf wall. You CAN compensate for the three-leaf problem by adding more mass to the leaves (more layers of drywall), or by increasing the depth of the air cavities between the leaves. It is possible, but not good, and not easy to calculate the MSM resonance for a 3-leaf system. Avoid if possible.

and if we are allowed to take it down.. Do we need to take down all the drywall from the complete wall (around the door framing too) or just in that section where the iso booth and control room are next to each other (iso booth is not the same length as the control room)

Probably just the parts that are in common, facing each other, and maybe a little extra. You could actually just punch very large holes in the drywall, if you don't feel like taking it all off. And "large" means "LARGE"!: As in a couple of square feet of hole in each panel, at least. As long as the air on either side of the inner "leaf" is well coupled through lots of large holes, that should do the trick. If this is a landlord issue, then why not just offer to commit in writing that you will put up new drywall on those studs when you eventually leave? If you are going to tear down all of your build when you leave, then nailing up a few sheets of drywall and painting it isn't going to be much extra work! - Stuart - - Stuart -