John Sayers' Recording Studio Design Forum

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My plans have changed a little now so these questions aren't all completely relevant. I will post back with updated plans and questions.

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Hello!

First post here so apologies if I don't exactly follow protocol! I promise I'm a quick learner!

So I'm about to start building a studio. The tenancy contract has been completed and the deposit paid. Its taken me three years to find a space that I'll be happy to call home for at least the next 3-5years so I'm excited to get cracking on it.

Edit.. Additional information

The Studio will be build in London.
The goal is to create a room within the building that achieves enough Sound Suppression / Transmission Loss so as not to inconvenience the offices underneath and to one side of the studio.
To a rough guide of the kind of sound generated from within.. From time to time we will be recording drummers within the room and potentially other musicians at the same time too.. It may occasionally get used for rehearsals where a small pa may be added but if that is too much its not a deal breaker.
Monitoring level wise.. I currently only own use nearfields consisting of ProAc Studio 100s and NS10s.. I do use these frequently on the upper end of their capability volume wise. I'm certain at some point I will add some larger midfields also.
The second goal once sufficient TL / Absorption is achieved is to create an acoustically balanced room that is a good balance between been tight and controlled for monitoring but still have life in the acoustics as I will be tracking within the same room. I understand that one will slightly compromise the other and vice versa but this is my own personal room that I am prepared to get used to using and is focussed on production and recording.. If I'm able to mix in there thats a massive bonus but not the end of the world if I have to go else where to mix.
The cosmetics must be inspiring and not too sterile!!


Just a precursor to the following details I'll provide and the questions that I'll ask. I've been working professionally as a producer for around 7 years, in that time I've had various programming rooms of my own and worked extensively in every different size and configuration of recording studio going, from the best and most expensive rooms to churches with no acoustic treatment to tiny box rooms in peoples back garden. I'm not going to claim to be an expert in studio design or acoustics but I have a decent set of ears and good ability to be realistic and absorb information quickly. I have been working my way through Rod Gervais' 'Build It Like The Pros', The Master Handbook of Acoustics and Phillip Newell's 'Recording Studio Design although have not read any front to back yet!

With regards to how this design / build will be carried out. I have a pretty limited budget. One that I hope is realistic but it is definitely on the limited side.
For that reason, I am trying my best to design the build myself and I have the help of my father who is a very talented all round craftsman / builder / joiner etc with all the necessary skills/trades to do most of the work, with the limitation of electrics and plumbing. I also have my nephew (age 21) helping us out to add man power and generally take care of the tasks that will not be a good use of time for myself/my father like sweeping / chipping cement off brick walls / carrying materials / making tea etc..
I have allowed budget for additional labour on the occasions where three people is not enough. I have also earmarked potential budget for some consultation with an acoustic specialist (if required).


So.. THE SPACE..

The space I have resides on the top (second) floor of brick walled / concrete floor / ceiling warehouse. The floor appears to be extremely thick and industrially built, as do the walls. From my conversations with the landlord there seems to be no worry as to how much weight the floors can hold and I will be getting some actual real world figures on this nest week.
The flat ceiling heigh is 10'4"/3.15m and has two triangular 'eve's that reach a maximum of 15'/4.57m at their highest point.
The depth of the room is 47'/14.33m and the width is 27'4"/8.33m
My studio will be constructed at the far end of the room and will be (gross space) depth 20'/6.1m and width 27'4"/8.33 giving a gross floor space of 546 SqFt/50.8 SqM.

Attached are a range of early 3d renders I have created in sketch up. Please bare in mine that the designs are rough and don't indicate my final design for wall/floor/ceiling assemblies, shape / angles / position of walls / windows / doors etc. They just represent on a basic level what I'm intending to build. I am in the process of putting technical drawings and a work flow together but would like some assistance here to help make various decisions on materials and correct implementation.

I should also mention that for the way I work it is preferable to have a single room operation with all the instruments and recording equipment to exist in one room. This is because most of the time I play a vast proportion of the instruments myself, so ease of access is preferable to absolute separation. I understand that there are compromises that arise due to this approach but I have become used to working like this and am accustom to the limitations. There is also the option of moving instruments of limited volume such as pianos etc into the main space outside of the studio where the acoustics will be more natural and ambient. vice versa, I will be laying the necessary lines so I can move my computer into the outside area of the studio if I have a band / drummer tracking in the studio and need to some separation.

I will follow this posts with specific questions relating to each stage of the build.

Thanks in advance for your time and knowledge, it is truly appreciated!

Blue May

*****************EDIT*****************

My plans have changed a little now so these questions aren't all completely relevant. I will post back with updated plans and questions.

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So here are the beginnings of how I'm planning to build the studio and some specific questions relating to various parts of the construction.

Existing Windows
First I must block the windows that will be unused.. the end wall of the building have windows the whole stretch of the wall, there are 13 windows in total and I plan to only use the middle 5.
I'm planning to fit basic stud framework around the unused windows, add low density loft insulation and seal with shuttering ply.

Floor / Base Assembly
I'm planning to build a raised floor that rests on Sylomer strips / Neoprene pads. I don't want to / can't use a concrete base as the implementation is to permanent to be take out easily when I eventually leave the space.

My plan is to create boxes made from 8'x4' / 2440mm x 1220mm x 18mm OSB or Plywood on the top and bottom that are braced with 47mm x 100mm wooden joists. These boxes will be filled to capacity with dry sand. My calculations are that given the floor space required this will take around 4m3 of sand and will weigh approx 6 metric tonnes.
I will join all the boxes before filling with sand and adding the top layer of OSB/Plywood.

Question -
Will this, coupled with the Sylomer underneath and the thick concrete floor offer effective isolation from above sound? for instance once the room is finished and the walls/ceiling / floor is air tight will the floor assembly offer enough mass and solidity to both isolate the vibration of a drummer's kick drum and and also isolate the noise from the monitors?

Walls
The basic concept I will follow is Mass Air Mass MAM assembly.
I plan to create two independent stud walls with offset joists.
I understand that for this to be effective the space in between these walls must be air tight.. So lets assume that I will do my upmost to fill any gap/space/crevice/hole with caulking.
The outer wall assembly will be rectangular and the inner wall assembly will be shaped according to what offers the best acoustic performance within the dimensions.. More questions on that later..
I have read and understand that the walls are most efficient when the layers are in this order -
Gypsum>Gypsum>Stud work and glass fibre fill >Air Gap>Stud word and glass fibre fill > Gypsum > Gypsum.

So here are my questions


First - Where the walls should be placed
I've found some conflict as to whether both walls should exist on the raised floor/base assembly. If both walls do exist on the platform assembly I can decouple the walls to an extent by placing them on neoprene/rubber strips.. but is it more beneficial to isolation and transmission loss to have the outer wall reside on the concrete existing floor and the inner wall to exist on the raised platform assembly?

Second - Gypsum
If I'm using gypsum on the very outer wall and the very inner wall, are 2 layers of 15mm standard gypsum board going to offer enough TL (in combination with the other elements) or would you recommend either adding a layer of fibre board on each side as well, if so in what position?
I'm familiar with mass law that every time you double mass you get an average increase in performance of 6db but doubling the Gypsum to 4 layers per side seems overkill and may take up too much space?
Having compared performance charts.. I can't notice a particularly improved performance between standard Gypsum and the more expensive soundshield plasterboard.. do any of you have an opinion on that?

Third - Glass Fibre / Rockwool
From what I have read, in this type of assembly, less dense glass fibre / rockwool is more effective at low frequency absorption / TL thank thinner and more rigid types.
Is this correct and could you recommend specifically a product that represents the best performance? if there are varying depths / densities please advise what type specifically.

Fourth - Distance and consideration surrounding (structural) brick walls
Is there any benefit in building the first gypsum/stud wall at a specific distance from the outer buildings brick wall? Obviously there needs to be enough distance so there is no structural energy transference but would a gap of 2"/3" be enough? Is there any reason that this gap should take precedence over the size of the airgap between the MAM assembly / Gypsum Stud walls?
Should outer brick wall be treated at all its self, should it have glass fibre added to the internal face?

Fifth - Width of airgap between the MAM assembly

What is an optimum spacing of the two stud walls? I imagine that the inner wall will an uneven quadrilateral shape so the distance between the walls will vary.
What is the minimum useful spacing to achieve good TL at low frequencies?
Is there ever such a point where you can have too much space for a effective sealed airgap?




I'll leave it there for now.... More questions on windows / doors / shape of internal room / bass traps / broadband absorption etc etc ....

Thanks again for all of your help!

Hi "Blue May", and welcome.

I'm in a bit of a rush right now, so just a few quick comments:

Ouch! That implies that you are NOT on the ground floor. Isolation will be hard to achieve...

Double-ouch! Second floor and drums... not a good combination. Impact noise, high levels. This is a challenge!

The PA won't change much: A few dB maybe. It's the drums that are the issue. That's the toughest of all instruments to isolate, and the loudest, too.

Great! That's a good goal that makes sense.

So it's basically just a tracking room / rehearsals space? No control room?

Even better! So you should have the basics by now. (The trick is to read those books back to front, not front to back: they seem to make more sense like that.... )

That's a good start. The issue will be the floor, since it has nothing but hollow empty space underneath. Have you done any testing, to find out how much isolation the floor is giving you right now? EG, set up a drum kit in the middle of that floor, tell the drummer to go wild, and go listen / measure downstairs, with an sound level meter? If not, I'd do that first, before anything else.

That's a decent sized space: any reason why you don't want to put a control room in there too, seeing that you have the room?

so one wall is basically a giant window? I think it will take more than a layer of plywood and some insulation to isolate that!

When you say "low density loft insulation", what do yo mean by that? What type of insulation and what density?

Ooops. So you are trying to float your floor? Have you read this? :

viewtopic.php?f=2&t=8173

sounds like you are just adding mass to the existing floor. It will still be a single leaf floor, and still governed by mass law. Even if you manage to double the mass of the existing floor, that would only buy you 6 dB of extra isolation, maximum. Probably more like 4 or 5.

But you don't say how much isolation you need (in terms of decibels) or how much you already have, so where did you come up with those numbers from? How did you figure the amount of mass, deflection, etc. for that floor, if you don't know how much isolation you need?

"Enough" for what? You haven't defined "enough" yet, so no-one can say... Until you get some real-world numbers to work with, then there's no saying what will be "enough" and what won't be.

Yes, no maybe. Not enough information to go on.

Studs. Joists are in floors/ceilings: Studs are in walls. Terminology is important! But why do you want to offset the studs? There's no research that I'm aware of that shows any huge advantage to doing that. i mean, you can if you want, and it sure won't hurt, but I'm wondering if you came across something new that suggest an advantage for offsetting the studs on the two leaves.

BOTH leaves must be totally airtight for maximum isolation. Whatever your outer leaf is, it must be sealed. The glass, for example, will be the outer leaf for that wall, so you need to make sure that each pane of glass is totally sealed into its frame, and that the frames are sealed to the walls, floor and ceiling. And, of course, that the glass is thick enough to attain the MSM resonance that you need.

I'm not sure I understand: You already HAVE an outer wall! You mentioned that one wall is glass, and the others are brick. So what "outer wall" are you talking about?

Yup! Assuming that you are talking about the right type and thickness of gypsum board, the right type of insulation (density, gas flow resistivity, etc.), and the right depth of air gap: By the way, the term "air gap" refers to the total distance between the leaves, including the insulation. Insulation is mostly air anyway. So don't get confused about that, as many people do. You have an air gap, part of which has insulation in it, and part of which does not.

That depends on what you are trying to do, how much isolation you need, etc.

No you can't, since you still have to attach the walls to the floor, with nails or bolts, thus short-circuiting the neoprene. The walls must be attached: it would be foolhardy to let them slide around on top of rubber mats...

If you decouple both properly, then yes. But it doesn't sound like you are doing that, and you didn't say how much isolation you need, so who knows? But I still don't see where you are going with this: you already HAVE your outer walls! They are part of the building! You cannot move those onto your semi-floated platform, even if you wanted to... All you can do is build the inner-leaf walls, which would be better on top of the floating floor, if it is floated correctly. But putting the walls on top of the floated floor changes everything! All the calculations that you did to come up with the right amount and mass, surface area, and deflection are now out the window, and you need to start again. Putting the walls on the floated floor means that the entire room is now floated, so ALL of the mass goes into the calculations: Walls, floors, ceiling, people, furniture, HVAC, electrical, equipment, instruments. It is all part of the floated mass, so it all has to be taken into account.

How many "outer walls" and "inner walls" are you planning to have???? This is two-leaf construction: There is ONE outer leaf (the existing building shell), and ONE inner leaf, which is the part that you need to build. Period.

Once again, "enough" for what? You don't give an numbers, so nobody can say. It's like saying "I have a piece of rope: Is it long enough?": Well, ummm... long enough for WHAT?????

Mass law does not apply to decoupled MSM construction. That's the whole point! Doubling the mass re-tunes the wall to a lower frequency, which may or may not be low enough for what you want. Above 2xf0 you get much steeper than mass law.

Exactly! Mass is mass, and sound waves do not care how much you paid for it! Get the least expensive mass that you can find to do the job. Normally, that is plain old fire-rated drywall (gypsum board). There are no magic materials that can beat the laws of physics, despite the claims by some manufacturers....

Less dense than what? Optimal density for mineral wool is around 50 kg/m3, roughly. Optimum density for fiberglass is around 30 kg/m3, roughly. In fact, it isn't really the density that matters: it is the gas flow resistivity, which bears somewhat of a relationship to density, sort of....

What do you mean by "first" one? You need ONLY one more! The brick wall is already there: that's your outer leaf. You only need to build the inner leaf, which is a single stud frame with one or more layers of drywall on only ONE side of the studs. Period.

And yes, the depth of the gap matters. That's the other major variable in the MSM equation.

I must be starting to sound like a broken record: "Enough for what?"

MSM is tuned. You tune it to 1/2 of the lowest frequency that you need to isolate (or lower). You do that by using the right amount of mass on each leaf, and the right gap between them. If there is not enough mass, or if the gap is to small, then the frequency is too high and the wall will not isolate at the frequency you wanted it to. It's that simple.

Ummmm... there's only ONE gap, and it IS the one in the MSM assembly. If you have two gaps, that implies three leaves, which is a bad, bad, bad idea. It means worse low frequency isolation. It means compensating by throwing money at it, with more mass and larger air gaps. But I don't understand the reason why you want to have three leaves.

The outer brick wall is the outer leaf. So yes, it will have insulation next to it, since that insualtion is the damping on the spring...

The right one for the frequency and isolation that you want!

Why? It can if you want to, but that depends on your room concept. Will this be an RFZ design, with splayed walls, or not? It could be rectangular too, if you prefer. And if it is only a tracking/rehearsal room, it could be any shape, within reason, even asymmetrical. Angles and shape are only critical for control rooms, but you didn't mention one of those...

What is the minimum frequency that you need to isolate, and what level of isolation do you need?

Nope. At least, not from the point of view of acoustics. Maybe your budget might run out, or your floor space might run out, but more gap is always better. It tunes f0 lower, and increase isolation.


- Stuart -

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I want this studio to amaze people. "That'll do" doesn't amaze people.

Hey Stuart,

Thanks for your response, I'll try to clear a few things up-



No not on the ground floor, However the building industrially built. it is thick concrete throughout.



Hopefully a challenge with some realistic chance of being achieved!! I've certainly worked in perfectly effective studios on higher floor in less structurally sound buildings than this one.



Yes I realise that a drum kit represents probably the loudest element i will use regularly. at the top end drum kits produce approximately 100-120db max, that coupled with the physical pressure produced on the floor makes them doubly hard to deal with right?



Its a control room first and foremost.. the difference being that I prefer to have all of my instruments in the same room with me.



Yes I admit I have been looking for answers to specific questions so far!



No scientific testing although I will make some tests this week.
I would estimate that the concrete floors are at least 2ft deep, Again I will check this measurement properly when I return to the space on monday.



The room is a control room.



Well there are windows that span the whole width of the wall. But the lower edge of the window starts at 5'4" / 1.63m above floor level. the windows are 4'7" / 1.4m high.

Low density loft insulation -
http://www.wickes.co.uk/200mm-loft-roll ... vt/161279/

The idea behind isolating them is, with the window size that I have planned for the studio that looks through to the already existing windows in the outer wall of the building, I will only be using the middle 7 window panes. So it seemed to make sense to me to board the other windows up. While doing that I thought I would add some thermal insulation - more related to heat loss in the rest of the room then anything directly linked to the studio structure.



Yes, I am planning to raise the floor on either Neoprene pads or Sylomer / Regufoam strips.

I have come across that thread, I will read in more detail.



How is it still a single leaf system if the sand filled boxes are raised on neoprene / sylomer? I'm not planning to just place sand filled boxes on the existing floor with out any attempt to decouple it with the aforementioned products.

Ok so onto how many DBs isolation i need.. I apologise for not stating this in DB terms! As formally mentioned the loudest instrument that will be used regularly will be a drum kit which reaches between 100-120db max, however the most constant sound source will be the sound coming from my monitors. I work fairly loud although as of this moment I only use various sets of nearfields for my monitoring that I don't imagine peak over 100dbs often.
So for a second maybe its easiest to ignore the people underneath and to one side of the studio and talk about how much noise is acceptable to travel from the 'Control Room' to the rest of my space.
My partner will have a writing space outside my studio in the 'Lounge' area, if you will. Both spaces will regularly be in use at the same time. So it will be important to isolate the studio enough so the people working outside can concentrate without being distracted by what is going on in the Studio/Control room. I'm afraid I can't give you a specific DB TL I need but imagine it may be as high as 70-85db when measured from my lounge area. This required amount will increase when we consider the people below and to the side of me.

As far as how I came about those figures relating to the weight of the sand, I based my calculations on the design of the floor boxes I am planning to construct.
If we imagine one chunk of the floor is made by attaching 2x3" / 47x75mm Joists around the edges of a 8'x4' / 2.4x1.2mx18mm OSB / Plywood board. I would then fill the empty space between the joists with dry sand and compact the sand until it was level with upper edge of the joists (3"/75mm depth of sand) I would then seal the box with another layer of 2.4x1.2mx18mm OSB / Plywood board. Multiples of this design could be attached together to create the desired floor space. and the whole assembly would rest on vibration isolating pads.
My calculations were as followed -
Approx weight of dry sand per m3 = 1602kg or 1.6metricTonnes.
Amount of sand required to fill (approx) 8.5m x 6m x 75mm = 3.825m3 x 1.6tonnes = 6.12tonnes

I understand that this is not based on scientific calculations or a desire to deal with an exact frequency range as of yet but I started to think about this when a concrete floating floor seemed impractical/impossible. As for as I can see it is an easy way to add a base structure that offers the density and mass that could get towards comparing to a concrete slab. Rod Gervais mentions in his book that a rockwool lined wooden floor offers no significant help with TL but he does mention sand filled wooden decks do offer some good results (p62 2nd edition).

Please do let me know if this design is floored (excuse the pun).. I'm completely prepared to be corrected / proved wrong at any point here! hence the reason for the existence of this thread.



Enough to significantly (In combination with the rest of the structure) lessen sound levels and physical vibration transference from within the room to the room below it and beside it.



Apologies.. I've never differentiated what a joist was depending on its orientation.



It was my understand that wooden studs perform less efficiently in terms of TL and Absorption than fibreglass / rockwool and for that reason it made more sense for them to be offset from eachother even if an air gap did exist in between. It just seems like something that is too simple to do that even if it has a slight difference its worth trying?
I would like more information on that front though.



Yes I understand this.



Ok, I realise that I may not fully understand the the three leaf issue yet and what part the actual structural brick walls / windows that already exist play in affecting the the walls I am planning to construct.

The way I have planned it so far, And please tell me if these plans are flawed, is as follows:-

My plan was for this whole structure to be completely independent of the structural walls / ceilings that already exist in the building.. with the only physical connection with the existing structure being the anti-vibration pads that will raise and partially decouple the floor of the Studio structure. This would mean that I don't plan on creating an air tight connection between the buildings existing brick walls and any of the studios walls. they wont come into contact at all.

In line with this plan my MAM assembly would start with constructing (what I'm calling) the outer wall or I guess the first leaf.. What I mean is the first stud wall that will be fixed to the edge of the floor assembly. This would be backed by 2 layers of standard 15mmGypsum which would connect to Studs and Fibre insulation. The a spacing would be left before (what I'm calling) the inner wall would be constructed using the same methods in reverse.

I am in the process of making Sketch up files to display this, Once they're done it will become clearer and you can tell me if what I'm planning is truly flawed.



Yes those are the questions I asked for advice on.. Specifically.. what type of Gypsum.. what type of fibre wool and what size air gap.



Can we ascertain that I need a lot of isolation... this is not a VO studio or a post production place.. This is a professional recording studio that I will use to carryout my work every day... I will mainly be listening back to my monitors at various levels but there will be occasional use of pianos / guitar amps / drum kits etc etc.. I need Isolation in line with any normal professional studio. As much as physically / financially possible.



Hence why I said 'To an extent..'



Please explain.



I'n not referring to the existing structural walls as the outer wall.. Apologies I should have made that clearer.. I do however need to understand better if I do create a two leaf system with two stud walls etc what affect the existing structural wall have sitting behind the studio walls.
I understand that, on a floated floor, all mass has to be taken in to account when calculating how much weight is loading the Neoprene/Sylomer pads and Concrete floor below that. But surely when talking about mass law with regards to the rule of doubling it gaining 6db in theory etc relates to each assembly separately to an extent? I understand that the approach has to be uniform throughout the build otherwise certain areas will be less effective than others..
I'm not sure I quite follow you on that.. Please expand.



Surely based on other builds it is possible for the existing structural walls to not for part of the two leaf system and for two newly build walls to create the two leaf system.. and the existing walls to offer additional isolation on top of what what the independent studio structure achieves.. Please explain if this is wrong and how come it doesn't work.. or link me to somewhere to read about it.



Although I didn't provide a figure of actual decibel reduction required I think I provided a fairly detailed description of the use of the studio and the environment in which it is to be built.. So I'm not sure if I completely follow the rope analogy.



I believe it does still apply.. Aren't the results just amplified with the introduction of more airspace and the lack of physical connection between the outer and inner wall?
Again.. I'm more than happy to be wrong and be corrected on any front.



Good.. I thought so.



No offence but are you trying to be pedantic? I appreciate you answering my thread but I think you are being a little difficult, especially as I read through some of your Stuart's Insanity Studio: Design phase and I think the people who helped you out at that stage were very patient.

Here is a quote from Rod Gervais.. I hope he wont mind me quoting... Would you ask him 'Less dense than what?' or would you take a guess at what he meant?

'Less dense insulation is better for low frequency isolation - it's just that simple.......

Rod'



Thanks..



Interesting, this is something I need to learn more about..



Only need one more if I was incorporating the buildings walls into the Studio.. which I don't plan to unless I haven't grasped what affect they will have regardless of their inclusion or not.

My question was when building an independent sound proof floating room with a MAM design.. How much does proximity to already existing and unincorporated walls / windows / beams etc etc have to the independent performance of the Studio structure?



So could someone direct me to the people who are managing to isolate their rooms by a significant level down past 40hz without having to build walls that are 4.29m deep?



I don't want three leaves.. Nor do I want Two sealed air gaps.. I want to build a completely new two leaf MAM assembly with ONE gap. What I am asking is how far from the existing structural walls (which the studio is not physically connected to) do I have to be for that assembly to to be effective.



The crux of the confusion - Does the brick wall have to be a leave purely because it is in close proximity to the studio assembly?



Thanks.. I good isolation stretching down to 30hz or more.



I'll deal with more acoustic related questions later in this thread when I've truly understood some of the fundamentals already laid out here.



.............



Thanks.. I am trying to be as detailed as possible and will take into account the information I need to provide.

I am almost finished making a proper sketch up file detailing the various stages of the planned design.. I'll upload this.. this should at least avoid confusion of what I'm proposing.. even if it is a pile of useless shit!! haha


Cheers.

I'm re planning now to incorporate the buildings existing walls into the design and only build one internal stud wall. I didn't fully take into account the effect of ignoring the existing walls and thought I could just create a completely independent structure without the building existing walls having a negative effect on TL.

Thanks

Thanks.