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isolation for recording guitars, acoustic instruments

Dear all,

This is my first post. Thank you all so much for an invaluable resource! I have read the rules, searched for a similar post but nothing was quite like I was looking for so here it is!

Ok so I'm planning to build a small studio at the bottom of my garden (in South East London. UK). My original plan was to have it built out of blockwork (concrete bricks) I got some quotes and the price was far too much for what I could afford so I had to go to plan B. As well sound engineering I have been a carpenter for a few years. Although I specialise on fitted furniture I have done some building work so I have decided to build it myself (timber structure) hiring some help for some stages.

My plan is as follows:

- Building size would be 5.5m x 3.5m x 2.6m

- Due to cost, ease of installation and environmental impact I have decided that rather than having a concrete slab laid I would like to use a system called Swift Plinth:

https://www.swiftfoundations.co.uk/swift-plinth-plus/

-The building's base would be made out of 10x2 treated timber sitting on the swift plinth

- My thought was to build the walls using 4x4 timber 600mm centres. The exterior would be covered with a layer 18mm osb board, a layer of 18mm external grade plywood and cladding.

- The cavity would be stuffed with insulation. 100mm Rockwool?

- The interior would have a layer of plywood and two layers of plasterboard with green glue between layers and caulking all gaps. Finally the interior would be plastered.

- The roof/ceiling would have same treatment as the walls.

- For the floor I would have a layer of 18mm plywood, a layer 22mm T&G chipboard flooring, A layer of flooring insulation and finally some T&G 18mm engineered flooring.

- I would like to have two top level windows (approx 400mm x 1000mm) Each window would have two panes of double glazed 6mm glass (I might sack this idea if it proves impractical and just do with no windows)

- I'm planning to have two doors. Each one made gluing 3 x 18mm pieces of plywood and using rubber seals all around

My main question here is about isolation. The room would be one open plan room. Generally I monitor at medium level with short loud bursts. I don't plan to record drums. Just acoustic instruments and guitar amps. For these I would build an enclosure so they don't make too much noise.

My nearest neighbour is 25m away.

My main questions are:

- Does this sound like something viable? In your opinion would I get enough isolation?

- Since the base frame would be slightly elevated would it be worth stuffing the cavities of the frame to stop it resonating? Would it be better to just have a concrete base laid?

- Do I make any sense?

Any help MUCH appreciated. Thanks in advance!

Cesar.

Comments

CGL Tue, 12/23/2014 - 06:13

DonnyThompson, post: 422669, member: 46114 wrote: I strongly urge you to buy this book:

http://www.amazon.com/dp/143545717X/?tag=r06fa-20

Hi Donny. Many thanks for your reply. I already have the book. There is lots of good advice there but also wanted to see other people's opinions. Also the book focuses more on building within an existing structure which is not something I'll be doing.

Space Tue, 12/30/2014 - 12:35

CGL, post: 422670, member: 48703 wrote: - Due to cost, ease of installation and environmental impact I have decided that rather than having a concrete slab laid I would like to use a system called Swift Plinth:

https://www.swiftfoundations.co.uk/swift-plinth-plus/

I wouldn't, here is why.

While I suspect the cost of this system with the framed floor will just about match what a concrete floor would cost it is not my only reason for dismissing it as viable. The main reason is that you will build an elevated wooden deck that will have a resonant frequency higher than a concrete substrate. That means the wooden floor will vibrate more readily than a solid concrete floor and will introduce frequencies at the resonant frequency of the less weighted wooden floor that can and will be a distraction while trying to record.

Essentially, a drum head is what you will build with this system.

An Earth damped concrete slab is the best first line of defense you can have in this type of consideration.

CGL Fri, 01/02/2015 - 04:10

Space, post: 422946, member: 32398 wrote: I wouldn't, here is why.

While I suspect the cost of this system with the framed floor will just about match what a concrete floor would cost it is not my only reason for dismissing it as viable. The main reason is that you will build an elevated wooden deck that will have a resonant frequency higher than a concrete substrate. That means the wooden floor will vibrate more readily than a solid concrete floor and will introduce frequencies at the resonant frequency of the less weighted wooden floor that can and will be a distraction while trying to record.

Essentially, a drum head is what you will build with this system.

An Earth damped concrete slab is the best first line of defense you can have in this type of consideration.

Dear Space,

Thank very much for your advice. I thought that might be the case but hoped hat being outside etc it might be less of an issue. Having said that I totally agree with you. Swift Plynth is ditched!

Regarding the rest o the construction do you think that the outlined plan would be sufficient to keep the sound in bearing in mind the surroundings etc? Would you advise to build a secondary room within the main building? Thanks in advance!

CGL Sun, 01/04/2015 - 12:36

Space, post: 423168, member: 32398 wrote: http://recording.org/index.php?threads/read-this-before-you-post.26684/

Hi Space,

Thanks for the link. I did read that thread before I posted and thought I was abiding by the rules. I did search for a similar post beforehand and couldn't find anything similar enough or with relevant advice. Also I haven't done any sound measurements because I'm not building within an existing structure. The plan is to build something from the ground up so I'm not sure what and how I need to measure before there is a building in place. In regards of how picky my neighbours are to be quite honest this building will be at the bottom of a vey long garden and the closest neighbours are those whose gardens mine backs onto. They live in a different street in a very populated area so I don't know them at all and probably never will. I thought I had given enough detail about how I plan to build the studio. I used measurements and materials. Am I missing anything?

Cheers.

kmetal Sun, 01/04/2015 - 13:59

CGL, post: 422663, member: 48703 wrote: Dear all,

This is my first post. Thank you all so much for an invaluable resource! I have read the rules, searched for a similar post but nothing was quite like I was looking for so here it is!

Ok so I'm planning to build a small studio at the bottom of my garden (in South East London. UK). My original plan was to have it built out of blockwork (concrete bricks) I got some quotes and the price was far too much for what I could afford so I had to go to plan B. As well sound engineering I have been a carpenter for a few years. Although I specialise on fitted furniture I have done some building work so I have decided to build it myself (timber structure) hiring some help for some stages.

My plan is as follows:

- Building size would be 5.5m x 3.5m x 2.6m

- Due to cost, ease of installation and environmental impact I have decided that rather than having a concrete slab laid I would like to use a system called Swift Plinth:

https://www.swiftfoundations.co.uk/swift-plinth-plus/

-The building's base would be made out of 10x2 treated timber sitting on the swift plinth

- My thought was to build the walls using 4x4 timber 600mm centres. The exterior would be covered with a layer 18mm osb board, a layer of 18mm external grade plywood and cladding.

- The cavity would be stuffed with insulation. 100mm Rockwool?

- The interior would have a layer of plywood and two layers of plasterboard with green glue between layers and caulking all gaps. Finally the interior would be plastered.

- The roof/ceiling would have same treatment as the walls.

- For the floor I would have a layer of 18mm plywood, a layer 22mm T&G chipboard flooring, A layer of flooring insulation and finally some T&G 18mm engineered flooring.

- I would like to have two top level windows (approx 400mm x 1000mm) Each window would have two panes of double glazed 6mm glass (I might sack this idea if it proves impractical and just do with no windows)

- I'm planning to have two doors. Each one made gluing 3 x 18mm pieces of plywood and using rubber seals all around

My main question here is about isolation. The room would be one open plan room. Generally I monitor at medium level with short loud bursts. I don't plan to record drums. Just acoustic instruments and guitar amps. For these I would build an enclosure so they don't make too much noise.

My nearest neighbour is 25m away.

My main questions are:

- Does this sound like something viable? In your opinion would I get enough isolation?

- Since the base frame would be slightly elevated would it be worth stuffing the cavities of the frame to stop it resonating? Would it be better to just have a concrete base laid?

- Do I make any sense?

Any help MUCH appreciated. Thanks in advance!!

Cesar.

Are the interior walls/ceiling going to be independent from the external ?

Also, any of the concepts in BLTP are the same whether it's new or existing construction, and it's very likely that you'll encounter some of the same situations, reguardless of new or existing construction.

CGL Sun, 01/04/2015 - 16:16

Hi Guys, thanks very much for your interest. Please read bellow. Perhaps worth mentioning that I use nearfield monitors (at the moment quested F11)

CGL, post: 422663, member: 48703 wrote: My main question here is about isolation. The room would be one open plan room. Generally I monitor at medium level with short loud bursts. I don't plan to record drums. Just acoustic instruments and guitar amps. For these I would build an enclosure so they don't make too much noise.

My original plan is to build one single room rather than a room within a room. One of my questions is whether this is viable or should I be looking at building an external structure and then a secondary one within?

Many thanks

kmetal Sun, 01/04/2015 - 18:05

Room within a room can give you a very significant amount of isolation, as opposed to the single leaf option, Especially in a wood framed structure. If you where using solid concrete block, double walls might not be necessary, some would weigh this when figuring costs of labour and materials. This is another area (double walls) where a concrete foundation comes into play, since in most typical cases I know of, both the outer shell and inner shell share a common foundation. And while this is a flanking path for sure, if your wood farmed walls make 4-6-8" of concrete foundation the weak link in the ISO, yr doing quite well.

Usually where a lot of people go wrong in your case CGL, is they want to force a control room and a tracking booth in inadequate cubic footage. Sinnce studio double walls usually average at around least 10-12" thick, your smart to keep your area wide open, because Imo it's better to have one really good room, than two compromised ones. And honestly I work in comercial facilities ( modest ones) and w out an assistant it's a real annoyance to set levels, and walk thru two rooms to move a mic, listen, rinse repeat. Planning for this w some remote qwerty keyboards mouses and screens would attack this. Keyword there being planning lol, fortunately that oversight is an easy fix.

I'm not familiar w the f11 model, but the questeds 8" mid fields, I have used in the past go LOUD. Obviously it's not a drum kit so you can turn them down, but that's really tough to say, unless you could give a rough idea of the DB level you typically use. And just for the sake of the fletcher Munson curve, I personally would never want to build from scratch anything that didn't allow me to listen up to the 90ish db range, without incident. Even the db meter free apps, will get you a rough ideA of SPL, my iPhone/pad meters read about 10db louder, or softer, ugh I forget which, than my radio shck meter. One thing to consider is that isolation or TL values, change with frequency, which is why SCT ratings aren't the best thing to go by. 80db at 60hz is a much more difficult to contain, than say 600hz, or 6k. If I rememeber the rule of thumb is isolation values are halved, with each drop in octave. Sorry too lazy to look it up :) but u get the idea. I use a free app from JL audio that has a db meter and RTA, obviously taken w a grain or 3 of salt, but not completely terrible.

Do you record vocals? With condenser mics? I only ask because, this is a consideration for keeping outside noise out, which in your case doesn't seem to be an issue.

CGL Sun, 01/11/2015 - 15:37

kmetal, post: 423208, member: 37533 wrote: Room within a room can give you a very significant amount of isolation, as opposed to the single leaf option, Especially in a wood framed structure. If you where using solid concrete block, double walls might not be necessary, some would weigh this when figuring costs of labour and materials. This is another area (double walls) where a concrete foundation comes into play, since in most typical cases I know of, both the outer shell and inner shell share a common foundation. And while this is a flanking path for sure, if your wood farmed walls make 4-6-8" of concrete foundation the weak link in the ISO, yr doing quite well.

Usually where a lot of people go wrong in your case CGL, is they want to force a control room and a tracking booth in inadequate cubic footage. Sinnce studio double walls usually average at around least 10-12" thick, your smart to keep your area wide open, because Imo it's better to have one really good room, than two compromised ones. And honestly I work in comercial facilities ( modest ones) and w out an assistant it's a real annoyance to set levels, and walk thru two rooms to move a mic, listen, rinse repeat. Planning for this w some remote qwerty keyboards mouses and screens would attack this. Keyword there being planning lol, fortunately that oversight is an easy fix.

I'm not familiar w the f11 model, but the questeds 8" mid fields, I have used in the past go LOUD. Obviously it's not a drum kit so you can turn them down, but that's really tough to say, unless you could give a rough idea of the DB level you typically use. And just for the sake of the fletcher Munson curve, I personally would never want to build from scratch anything that didn't allow me to listen up to the 90ish db range, without incident. Even the db meter free apps, will get you a rough ideA of SPL, my iPhone/pad meters read about 10db louder, or softer, ugh I forget which, than my radio shck meter. One thing to consider is that isolation or TL values, change with frequency, which is why SCT ratings aren't the best thing to go by. 80db at 60hz is a much more difficult to contain, than say 600hz, or 6k. If I rememeber the rule of thumb is isolation values are halved, with each drop in octave. Sorry too lazy to look it up :) but u get the idea. I use a free app from JL audio that has a db meter and RTA, obviously taken w a grain or 3 of salt, but not completely terrible.

Do you record vocals? With condenser mics? I only ask because, this is a consideration for keeping outside noise out, which in your case doesn't seem to be an issue.

Dear Kmetal,

Sorry about my slow reply. I have been away for a few days. Your input is very much appreciated.
To answer your question yes, I would be recording vocals but you are right to assume that outside noise is not an issue. I am more worried about trying not to make too much noise! At this point I am tempted to have some more quotes for having the building done using concrete blocks. If I factor in the time it would take me to build it (not getting paid) and materials I might not be making a great (or any) saving. I will have a good think about it. I will also visit a colleague's timber framed, single leaf studio which he claims delivers pretty good isolation and will report back!

CGL Mon, 02/09/2015 - 16:02

kmetal, post: 423208, member: 37533 wrote: Room within a room can give you a very significant amount of isolation, as opposed to the single leaf option, Especially in a wood framed structure. If you where using solid concrete block, double walls might not be necessary, some would weigh this when figuring costs of labour and materials. This is another area (double walls) where a concrete foundation comes into play, since in most typical cases I know of, both the outer shell and inner shell share a common foundation. And while this is a flanking path for sure, if your wood farmed walls make 4-6-8" of concrete foundation the weak link in the ISO, yr doing quite well.

Usually where a lot of people go wrong in your case CGL, is they want to force a control room and a tracking booth in inadequate cubic footage. Sinnce studio double walls usually average at around least 10-12" thick, your smart to keep your area wide open, because Imo it's better to have one really good room, than two compromised ones. And honestly I work in comercial facilities ( modest ones) and w out an assistant it's a real annoyance to set levels, and walk thru two rooms to move a mic, listen, rinse repeat. Planning for this w some remote qwerty keyboards mouses and screens would attack this. Keyword there being planning lol, fortunately that oversight is an easy fix.

I'm not familiar w the f11 model, but the questeds 8" mid fields, I have used in the past go LOUD. Obviously it's not a drum kit so you can turn them down, but that's really tough to say, unless you could give a rough idea of the DB level you typically use. And just for the sake of the fletcher Munson curve, I personally would never want to build from scratch anything that didn't allow me to listen up to the 90ish db range, without incident. Even the db meter free apps, will get you a rough ideA of SPL, my iPhone/pad meters read about 10db louder, or softer, ugh I forget which, than my radio shck meter. One thing to consider is that isolation or TL values, change with frequency, which is why SCT ratings aren't the best thing to go by. 80db at 60hz is a much more difficult to contain, than say 600hz, or 6k. If I rememeber the rule of thumb is isolation values are halved, with each drop in octave. Sorry too lazy to look it up :) but u get the idea. I use a free app from JL audio that has a db meter and RTA, obviously taken w a grain or 3 of salt, but not completely terrible.

Do you record vocals? With condenser mics? I only ask because, this is a consideration for keeping outside noise out, which in your case doesn't seem to be an issue.

Dear all,

It's been long but I finally managed to go and take a look at the aforementioned friend's studio. He built it in his garden using the following method:

- Concrete base
- 3m width, 3.5m length and 2.4m height single leaf timber framed building
- He used 4x2" timber for the walls and 6x2 for the roof. The building is sitting on 4x2" joists (which are sitting straight on the concrete) and a layer of 18mm plywood.
- Externally covered with 18mm external grade plywood (walls and roof) Compacted rockwool in the cavities. Inside it has one layer of plasterboard, one layer of iso rubber (on walls, ceiling and floor), a second layer of plasterboard and some floor boards on the floor.
- For the door he glued two fire doors together. There are some attempts at sealing on the door jambs
- There is one window about 600x1000mm with two panes of double glazed glass. Not quite properly sealed.

This is as much detail as I could get out of my friend!

Ok so I followed Kmetal's advice and downloaded the JL audio app. Turned the music up (very loud) and metered 95db in front of the speakers. Stepped out of the room into the garden and on the door and window side it read 55db 1m away from building and 50db 2m away. I went around the only other side I could access (the other two were right by the garden's boundaries) where there are no doors or windows and it metered 48db 1m away.

Personally I thought the isolation was pretty good. I believe that with a couple of tweaks (better door and better sealing) it can be improved and bearing in mind that the nearest house to my studio would be about 25m away that level of isolation should be sufficient. I would rarely play the music that loud anyway.

Apparently the iso rubber was fairly expensive. In your opinion is this a crucial element? is there a cheaper alternative/method? What do you gentlemen think about all of the above?

Many thanks!

Space Mon, 02/09/2015 - 17:13

"The building is sitting on 4x2" joists (which are sitting straight on the concrete) and a layer of 18mm plywood."

Except for that, sounds good. A concrete Earth damped floor is all you need. Any addition to this floor in an attempt to construct a mass/air/mass assembly should have matching mass. Concrete is roughly 98 pounds a cubic foot and the addition of a wooden deck does not have the same mass. And as we discussed before, its a drum head.

CGL Tue, 02/10/2015 - 01:02

Space, post: 424925, member: 32398 wrote: "The building is sitting on 4x2" joists (which are sitting straight on the concrete) and a layer of 18mm plywood."

Except for that, sounds good. A concrete Earth damped floor is all you need. Any addition to this floor in an attempt to construct a mass/air/mass assembly should have matching mass. Concrete is roughly 98 pounds a cubic foot and the addition of a wooden deck does not have the same mass. And as we discussed before, its a drum head.

Yes! I did think about hat at the time! so do you suggest that the walls should be sitting straight onto the concrete base?

kmetal Tue, 02/10/2015 - 03:02

Nice! Good stuff, barring the wood deck design. Curious how it sounded in there, and if you got to hear any recordings in there?

Sealing is very important, and the main objective is that the seal makes contact along the whole length. Fortunately glazing tape, and weatherstripping is fairly painless to install, and most people could do it well if they take watever time they need to be neat. That said doors are a major source of agony for me an I don't have them down to an exact science. The double/triple seals help eliminate the chance that their is a breach in the exact same spot three times. From what I've gathered the actual material of the seal isn't particularly important as long as it seals, but different types will wear differently. If I remember correctly dark pines (madmax) used stuff like this for his secondary seals, on his doors, but it might have been another build, or he may have gone w something different.

Windows are cool because they don't move lol, so a bit easier on that front, but glass is heavy too, and expensive, so maybe equally as painful?

One way to do it is build directly in the concrete. since it's one room you don't really have to run ducting in the foundation, but it could be useful maybe. The general idea is that the concrete does not transmit sound well, like wood does. there's different variations on slab designs that range from simple to elaborate. I guess in its simplest form it would be a basic reinforced slab, probably require some special appointments, based on the additional load the ISO construction will impart. Pi really don't have any hands on experience with new foundations, or purpose built ones, so I dontnknow the finer details of that. Inhave been in a couple modest studios with rooms built in foundations residential and comercial, and it never seems to the weakest link.

I think the idea is that if a wooden deck is going to be used it needs to be dampened so it doesn't resonate. I've only used sand filled decks for the couple booths I've need to and it seems to be fine, and operate as advertised. If I didn't need one I wouldnt put a wooden deck in If for no other reason than saving money and labor. I think in general it's basically a wash acoustically if it's deadend.

CGL Wed, 02/11/2015 - 09:15

To answer your question Kmetal I listened to some heavy rock for metering purposes. As far as I could tell it sounded pretty good. One interesting thing the owner mentioned is that when he recorded drums in the room (using an electronic kit) the kick drum was clearly audible outside. I imagine that must be caused by the wooden deck!

So it is decided. I will build it with the walls sitting straight on the concrete. Perhaps I will have a course or two of bricks laid for the walls to go on as a damp protection measure.

Any thoughts on the iso rubber? In your opinion is it a must do?

kmetal Thu, 02/12/2015 - 03:42

CGL, post: 424953, member: 48703 wrote: To answer your question Kmetal I listened to some heavy rock for metering purposes. As far as I could tell it sounded pretty good. One interesting thing the owner mentioned is that when he recorded drums in the room (using an electronic kit) the kick drum was clearly audible outside. I imagine that must be caused by the wooden deck!

So it is decided. I will build it with the walls sitting straight on the concrete. Perhaps I will have a course or two of bricks laid for the walls to go on as a damp protection measure.

Any thoughts on the iso rubber? In your opinion is it a must do?

Make sure you involve professionals involved re guarding the foundation design. It is specialized in that it is holding an un commonly massive structure, relative to tidal backyard sheds and garages. I know I won't be much help in this area besides the basics.

There could be many reasons why this other studio was leaking sound, wood deck being one of them. Are you using an acoustic drum kit?

What is ISO rubber? Haven't heard of it.

CGL Thu, 02/12/2015 - 12:04

kmetal, post: 424959, member: 37533 wrote: Make sure you involve professionals involved re guarding the foundation design. It is specialized in that it is holding an un commonly massive structure, relative to tidal backyard sheds and garages. I know I won't be much help in this area besides the basics.

There could be many reasons why this other studio was leaking sound, wood deck being one of them. Are you using an acoustic drum kit?

What is ISO rubber? Haven't heard of it.

Absolutely. I already had an architect some time ago draw some plans and he speced a base for the building so the foundation would be done to his plans.

I will not be recording drums so that's not something to worry about.

Here is a link to the iso rubber:

http://www.thermal-economics.co.uk/main_products/isorubber-base

I think iso rubber is mainly designed to be used as an underlay on floors. To eliminate impact noise. He used it on floor, walls and ceiling. Sandwiched between two layers of plasterboard.

kmetal Fri, 02/13/2015 - 13:08

I have no experience with thermal rubber and the data sheet had sparse technical data.

An architect by trade doesn't have to know anything of acoustics or acoustical construction. You need professionals in this, far more than an architect.

My rule of thumb, is if it ain't in the book, I probably don't need it, in general. Specific things inevitably crop up and require special research. But in the conceptual design phase, I have found no need to i corperate systems, or products other than was in the book. It's all based of numbers, which gives, a basic jumping off point.

If there was some grand shortcut to isolation or sound quality, I think we would know about it probably by now. So I always just stick w the basics and well known things, and keep my expectations realistic. I'm not saying the thermal rubber doesn't work, I'm saying I don't know, or know of anyone who has used this.

CGL Sat, 02/14/2015 - 15:40

kmetal, post: 425027, member: 37533 wrote: I have no experience with thermal rubber and the data sheet had sparse technical data.

An architect by trade doesn't have to know anything of acoustics or acoustical construction. You need professionals in this, far more than an architect.

My rule of thumb, is if it ain't in the book, I probably don't need it, in general. Specific things inevitably crop up and require special research. But in the conceptual design phase, I have found no need to i corperate systems, or products other than was in the book. It's all based of numbers, which gives, a basic jumping off point.

If there was some grand shortcut to isolation or sound quality, I think we would know about it probably by now. So I always just stick w the basics and well known things, and keep my expectations realistic. I'm not saying the thermal rubber doesn't work, I'm saying I don't know, or know of anyone who has used this.

Hi Space. The architect is not the one that suggested the iso rubber! I simply had to employ his services because I had to apply for permission from my local council to build the studio in the garden. The only thing I will use from his plans is the size of the building! (and the spec of the base which is the regular compacted hardcore/damp membrane/concrete)
The iso rubber was used in the studio I visited. To be honest I feel a bit like you! I'm not sure how much difference it would make and it is expensive. I will go without it.

Space Sun, 02/15/2015 - 09:29

I have seen ISO rubber used thru the years. The thinking is that there is some measure of decoupling. The truth is that decoupling requires some pretty specific math to ensure that the pressure is accurate enough too actually produce the desired effect. Reality is that it most often becomes simply a barrier underneath the wall plate and a very uneven concrete surface that allows the rubber to fill in any air space.

To that end, the rubber is very helpful. In respect to decoupling, I wouldn't consider it unless I was willing to go thru the math of the material and attempt to get the required weight distributing in order.

In respect to the concrete slab, a concern of kmetal, I have been involved with hundreds of builds thru the years and there has not been a case that required any modifications of the existing slab OR the need for anyone of a professional level to get involved for the simple installation of an interior framed area.

Granted, if a decoupled isolated slab were part of this build or modifications for a multi room environment were being considered, then there would be a need for drawings to support the wanted design with approval from the powers that be. Not always, but if your driven to do it right, then it will require some local code approval and that requires professionals.

CGL Sun, 02/15/2015 - 12:49

Space, post: 425095, member: 32398 wrote: I have seen ISO rubber used thru the years. The thinking is that there is some measure of decoupling. The truth is that decoupling requires some pretty specific math to ensure that the pressure is accurate enough too actually produce the desired effect. Reality is that it most often becomes simply a barrier underneath the wall plate and a very uneven concrete surface that allows the rubber to fill in any air space.

To that end, the rubber is very helpful. In respect to decoupling, I wouldn't consider it unless I was willing to go thru the math of the material and attempt to get the required weight distributing in order.

In respect to the concrete slab, a concern of kmetal, I have been involved with hundreds of builds thru the years and there has not been a case that required any modifications of the existing slab OR the need for anyone of a professional level to get involved for the simple installation of an interior framed area.

Granted, if a decoupled isolated slab were part of this build or modifications for a multi room environment were being considered, then there would be a need for drawings to support the wanted design with approval from the powers that be. Not always, but if your driven to do it right, then it will require some local code approval and that requires professionals.

Hi Space,

Many thanks for the info regarding both the iso rubber and the base. I'm going to go without it (rubber) I will build the studio to my original (now slightly tweaked) plan and see what the isolation is like. Having seen (and heard) my friend's studio and bearing in mind that with your help the design will already be improved (compared to his) I am confident that I will obtain the level of isolation that I need. After all what I'm after is a good, comfortable room to work in that won't let too much noise out!

anonymous Sat, 03/07/2015 - 14:40

CGL, post: 422663, member: 48703 wrote: My main question here is about isolation. The room would be one open plan room. Generally I monitor at medium level with short loud bursts. I don't plan to record drums. Just acoustic instruments and guitar amps. For these I would build an enclosure so they don't make too much noise.

I haven't read the thread but read the OP. I've been working like this for decades. Its smart and works.
VocalBooth sent me a stellar Amp enclosure years back, is crazy awesome. You can put a good size amp in it and crank it, no one hears a thing. Excellent for re-amping all sorts of things. Make one if you don't want to buy one.

it has a fan, its super quiet, runs cool. Mine is on wheels so I can roll it around. Awesome.


The kind of studio you are putting together is choice and very economical. Within reason, I can make music in my home studio that will rival the best. If you need more space that you don't have, rent a hall for the weekend.
Rather than buying or building a studio for the occasional big room needed, I saved hundreds of thousands in studio construction costs, invested in world class mobile tracking equipment and go on location, track what I need, bring it back to my killer control room and put it together.
Get acoustic treatment, clouds etc , learn about sound replacement, learn to mix. You will love your life and people will be amazed once you get good at it!

CGL Fri, 09/18/2015 - 12:50

Hello all,

It's been a while. I'm finally ready to start the construction of the studio in a couple of weeks. The concrete base has been laid and is ready for the build.

Just to recap this is my plan:

1 - Building dimensions will be 5.5m x 3.5m
2- Construction will be made using 4x2 timber for the walls and 6x2 for the roof. The walls will be fixed straight to the concrete (as suggested earlier in this thread)
3- Outside it will have 2 layers of 18mm OSB board plus a layer of cladding
4 - Compacted rockwool for the cavity
5 - Inside it will have 1 layer of 18mm OSB board plus 1 layer of plasterboard
6 - Very heavy solid core door (maybe two doors with an air gap in the middle?)
7 - No windows

Please refer earlier in the thread regarding neighbours, amount of noise I'll make etc...

Now does this sound reasonable? Are all those layers of OSB a bit of an overkill? I read somewhere that, if doing two layers of something (like the two layers of external 18mm OSB I plan to do) it is better to do two different thicknesses (ie: 18mm and 11mm) //what do you gentlemen think about that?

I look forward to some feedback. Thanks n advance!

DonnyThompson Fri, 09/18/2015 - 23:24

CGL, post: 432545, member: 48703 wrote: I look forward to some feedback. Thanks n advance!

( @CGL , @kmetal , @Brien Holcombe )

Can I ask what you are doing for ventilation?

The reason I ask is because I've been in rooms that are well-isolated - but that during the build, ventilation of fresh air was overlooked- either unintentionally because it simply wasn't considered - or intentionally, in an effort to maximize isolation; and after awhile, if you are in a room that lacks sufficient ventilation long enough, you do start to "feel" it.

It can manifest itself in a number of ways; people can start to feel lethargic and logy, some may start to feel claustrophobic, others can get anxious, or tempers can start to run short ... any of which can result in dramatically decreased creativity and performance quality.

I'm not saying that your room is like this; I'm just curious as to if - and/or how - you handled that part of the build.

d.

kmetal Sat, 09/19/2015 - 15:53

I didn't see any mention of hvac in the quick look over I did. This was a bit foggy for me, I think that the foundation hadn't been deteriemined, which is where it left off? People must breathe tho.

CGL, post: 432545, member: 48703 wrote: Please refer earlier in the thread regarding neighbours, amount of noise I'll make etc...

Now does this sound reasonable? Are all those layers of OSB a bit of an overkill? I read somewhere that, if doing two layers of something (like the two layers of external 18mm OSB I plan to do) it is better to do two different thicknesses (ie: 18mm and 11mm) //what do you gentlemen think about that?

I look forward to some feedback. Thanks n advance!

There isn't any advantage in general to having two different thicknesses of plywood/drywall for the purpose of massing up ISO walls. People confuse using two different thickness on sheathing layers, with having the actual isolation wall leafs of different thicknesses. For instance in a typical double glazed studio window you would use two different thicknesses of glass, for the front pane and the back pain. since each pane is acting independently of each other, you don't want them rattled get at exactly the same resonant frequency. When your adding multiple layers directly on top of each other eaxh layer is acting as one big mass sheet, so in general the more mass the better.

There's absolutely nothing overkill about what your proposing and possibly under kill. 95-100db is a fair amount to block I think having the amount is layers your suggesting won't block the low end power at those volumes levels.

CGL Sat, 09/19/2015 - 16:30

DonnyThompson, post: 432557, member: 46114 wrote: Can I ask what you are doing for ventilation?

I am planning to have a simple heat recovery ventilation system such as this:

http://www.envirovent.com/home-ventilation/products/heat-recovery-systems/heatsava/

Hopefully it will be enough to keep the room relatively fresh. Most of the time It will just be myself there. My concern is sound leaking through it. Does anyone think that could be an issue?

Also talking about sound leakage I was thinking about installing some sun tunnels to bring in some natural light to the room. In your opinion would this be a bad idea?

http://www.addlite.co.uk/roof-windows/sloped-ceiling-sun-pipe?diameter=230mm&gclid=Cj0KEQjwj_SvBRC7k4DfkLHiuMABEiQAvPOaqfQKIvYA0IyPUiSI9goPiGH9oF-ZjWOQZngK8MG_fT8aAog38P8HAQ

kmetal, post: 432567, member: 37533 wrote: There isn't any advantage in general to having two different thicknesses of plywood/drywall for the purpose of massing up ISO walls. People confuse using two different thickness on sheathing layers, with having the actual isolation wall leafs of different thicknesses. For instance in a typical double glazed studio window you would use two different thicknesses of glass, for the front pane and the back pain. since each pane is acting independently of each other, you don't want them rattled get at exactly the same resonant frequency. When your adding multiple layers directly on top of each other eaxh layer is acting as one big mass sheet, so in general the more mass the better.

There's absolutely nothing overkill about what your proposing and possibly under kill. 95-100db is a fair amount to block I think having the amount is layers your suggesting won't block the low end power at those volumes levels.

Loud and clear! I'll keep the design as it is. In fact for the internal layers I had originally planned to have two layers of plasterboard rather than only one so I'll also stick to that. 95db was what I used for metering purposes at my friend's studio but I would very very rarely play music that loud so hopefully that should be sufficient isolation!

OBrien Mon, 09/21/2015 - 19:42

I agree with kmetal, but not for the same reasons. Different thicknesses of glass are used in a mass/air/mass configuration but it is not because they may rattle at the same frequency. The thickness of the material, any material, will have a critical frequency. This is an acoustic hole that allows sound/vibration to pass thru as if no barrier existed.

The graphic above shows the critical frequency of 4mm, 8mm which are the ones we are interested in at the moment. The 4mm glass has a critical frequency at around 3200Hz. The 8mm glass has a critical frequency of around 1600Hz.

You may not have noticed but the doubling of the glass (mass) divided the critical frequency in half. If you had a piece of this same glass and it was 16mm you could expect the CF to move down to around 800Hz.

So they both have holes acoustically speaking. But if you place one piece of glass in one wall and the other in the opposite wall you have a better ability to plug this acoustic hole since the sound that passes through the 32ooHz hole will be barred from passage through the next glass pane that has the 1600Hz critical frequency.

Adding mass directly on top of existing mass, well, they may have been thinking the same thing there as well. That and refraction. With refraction as a tool the thinking is this. Think of a clear body of water. Now push a stick diretly into the water until you hit the bottom. When you look at the stick it seems to have "bent" downward. This is the visual companion to refraction.

Vibrations move faster through solids, the more mass it has the faster the vibration will travel.

So using dis-similier materials the thinking is that you alter the path the sound takes which takes energy from the sound wave thereby creating a better isolation assembly. But the effect is so small that it is not worth the effort.

Using more of the same mass in a wall or overhead assembly is the answer. The overall TL of the added mass moves up with the addition of another panel which means a better isolation assembly.

Back to the windows.

What happens if you use, say, thermal glass in a double wall assembly? If you have a double insulated piece of glass like at post 47 http://recording.org/threads/new-small-pro-studio.58878/page-3 you have FOUR pieces of glass with the same critical frequency...It IS a free pass acoustical tunnel directly in and out of the rooms, from either side to the other.

When the control room OR the tracking room is tested, if they ever are, there will be a spike at the critical frequency of the glass in these double insulated panels. People will scratch thier head for weeks trying to figure out why there is so much "what ever the critical frequency of that glass is" is getting into the room and why every time it is eq'ed out...it just comes right back in.

And that is why you do not use double insulated glass;) Well that and multiple air spaces which are known to reduce the ability of an assembly to isolate.

x

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