# Sound insulating a new recording studio



## Guest

Hi all,
my name is Quinto and, before of all, I beg you pardon for my english writing. It was from school, now it is from international forums, which is terrible  

I'm designing and building our new studio. We are 6 men and 2 women, we registered a company ("SK") and started with this new adventure.
It will be a commercial studio.
We have a relatively low budget, I'm sure that this makes the design a lot more interesting, because it is what most people has.

I've looked for the place, convinced people, looked for docs (I'm an engineer but i hadn't specific background), designed the studio, designed the furnitures, used a big hammer to remove existing walls, looked for waste removal, bought materials, bought instruments, built devices like preamps.
I'm going to build the insulation and devices for acoustics.

I'd like to show the progresses here, because I like "internet collaboration" a lot and because I'd like to get some advice (I could be wrong in some critical points).

************

This is what we are going to build (drawings and photos will be on www.skstudio.it as long as works will go on):
- we have a single room: 21m x 5m x 3.15m(h)
- there is a single door on one side, 4.5m wide
- we decided to build a recording room in the opposite side to entrance, 5 x 8m
- on the short side (5m) there will be the control room, 4m wide x 5m long
- resulting height after insulation will be 2.80m

We will build a structure with iron, then we will build dry walls and ceiling on it.

These are the materials for walls:

- drywall 1,3cm + rockwool 120 kg/m3 6cm + rockwool 40 kg/m3 4cm + drywall coupled with lead

These are the materials for ceiling:

- poliuretan-metal composite panels (used for external ceilings)
- rockwool 120 kg/m3 6cm + rockwool 40 kg/m3 4cm + drywall coupled with lead
We are still considering the alternative of replacing lead for ceiling with resonating panels (built by ourself)

The ceiling will be placed over the structure, the walls will be placed inside.

Floor:
The room is at "zero level", but there is the structure under the floor, we found that jumping on the floor we can feel the walls vibrating, so we decided to insulate it
- 1cm "isolgomma R" (www.isolgomma.it)
- 2cm wood
- 0.5cm isolgomma
- 1cm wood
- parquet (or wood, instead of 1cmwood + parquet)

Windows:
- two glasses angled about 20° each other and placed 10cm min apart

Doors:
- a couple of REI120 for recording room and a single REI120 for control room

Between drywalls, panels and iron: bi-adhesive rubber band

Between iron structure and floor: the same as floor (rubber+wood+rubber+wood)

This is the raw description of what we are going to do. Today I'm going to receive the iron, to be soldered in place.

Sorry for this huge post!:whew: 

I'll be able to post some drawings and photos in a while.

There is a very long work behing all this, because I had to design while looking for available materials and a lot of other aspects, of course.

I'm going to tell about acoustic control in a nother thread, because I feel it like a completely different argument (even though it isn't independent, of course)

Any comment/advice will be very appreciated, and I'll be happy to answer to any question about materials and anything else.

Quinto


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## Guest

Hi Quinto. Welcome to the forum!

A lot of info in your post. :reading: :bigsmile: 

Perhaps you could break it down a bit for us and ask a couple of questions at a time?

A studio build diary would be great!

I'm not really a building expert but I'm sure the folks here will be happy to help.

Good luck

Matthew


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## Guest

Hi Matthew:bigsmile: 

yes, I'll break it down for sure, I wanted to give a complete view as a starting point:whew: 

The "studio build diary" is the right concept and it is what I'm going to do, I sould be able to upload the first snapshots and a general drawing tomorrow...


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## Guest

Hi Quinto. That's great. Looking foward to the pictures. Sounds like you have a great project ahead of you.

And by the way, your english is fine  

Matthew


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## Danny

For a studio you really do not want to allow any sound to get in from outside the studio. Double glazing and good rubber compression seals around your windows and doors will help reduce this problem for a small price.


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## Guest

Hi Quinto. Welcome to the forum!

Will you be making an English version of your website? :bigsmile:

I was there, and I'm sorry I don't understand Italian.:dunno:

Sounds like your studio is quite the undertaking. Why are you using lead in your construction? What thickness is the lead and is the drywall attached to the lead?


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## Guest

Bryan Nemecek said:


> Hi Quinto. Welcome to the forum!


Hi, thanks:bigsmile: 



Bryan Nemecek said:


> Will you be making an English version of your website? :bigsmile:
> I was there, and I'm sorry I don't understand Italian.:dunno:


I'll do an english version for the "studio construction diary". I'll try to do some other pages in english. www.sknote.it is in english because it is for worldwide application, while www.skstudio.it is in italian because it is born for "local" application. I'll try to keep the "non-local" pages in english, too...



Bryan Nemecek said:


> Sounds like your studio is quite the undertaking. Why are you using lead in your construction? What thickness is the lead and is the drywall attached to the lead?


I'm using lead because I need to stop low frequencies. It needs mass and lead seems to be the only true solution.

I'm going to use drywall coupled with lead. The same used for x-ray rooms but with less lead.
I will install 0.5mm lead.

I'm going to use resonating membranes, too, for low frequencies


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## Wayne A. Pflughaupt

> I'm using lead because I need to stop low frequencies. It needs mass and lead seems to be the only true solution.


Have you seen anything to indicate if that will work or not? Just curious, because as far as I know, “mass” typically means at least a few inches of concrete.

Regards,
Wayne


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## Guest

Wayne A. Pflughaupt said:


> Have you seen anything to indicate if that will work or not? Just curious, because as far as I know, “mass” typically means at least a few inches of concrete.
> 
> Regards,
> Wayne


No direct experience (I'll do a lot of tests while building this studio) but this is a good reference:
http://www.ndasrl.it/schedaprodotto.asp?ID_Prodotto=6

There are curves for several materials, there...


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## Guest

I just wanted to show you our great recording studio:










(I'm the tall one :bigsmile: )

This is to say: don't think it's easy :whistling:

:laugh:


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## Guest

The snapshot is good. We were removing concrete with the hammer so the flash reflected on the powder...

On the right: we are building the furnitures, you can see the console with racks and audio monitor shelves

On the left: iron (for the structure for playing room and monitoring room) and rubber (for the floor)

This is the starting point of our studio-building-diary...


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## Guest

The works go on...










Preparing insulation between the structure and the floor (waiting for the glue to make effect)...


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## boyce

Hi quintosardo, from your photo, I believe you are building a new wall which will line up the room as a box, we did build some home studio, most time we like to make the wall not parallel, especially for a small room, just off set one side of the wall couple degree, it will save you lot of time to look for the mic sweet spot.


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## Guest

*Non- Parallell Walls Myth*-

This will surely be too late to help but might help others - do not fall into the non-paralell walls trap. All that NP walls do is make identifying and taming room modes more difficult if not downright impossible without serious test equipment eg Linear-X, and you can finish up chasing problems for evermore. By having a regular room you can easily identify immediate mode problems by calculation.


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## boyce

Andrew W said:


> *Non- Parallell Walls Myth*-
> 
> This will surely be too late to help but might help others - do not fall into the non-paralell walls trap. All that NP walls do is make identifying and taming room modes more difficult if not downright impossible without serious test equipment eg Linear-X, and you can finish up chasing problems for evermore. By having a regular room you can easily identify immediate mode problems by calculation.


Can you provide more detail about Linear-X? Don't understand which serious product you use? For our job, we alway build the wall non -paralell, after drywall / carpet, it will take us about 2 - 4 hours to do the test / calculation with DIRAC software. Why non-parallel is a trap?!! onder:


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## brucek

> All that NP walls do is make identifying and taming room modes more difficult


That's the first time I've heard this. It's not that I doubt it, but my understanding is that 4 non-parallel walls don't allow any standing waves a chance to build. 

Here's a small article that fits nicely into my novice knowledge of the subject.



> Non-parallel walls
> 
> RR Audio designs enclosures based upon the fact that parallel walls cause standing waves inside the enclosure which cause certain frequencies to predominate at wavelengths based upon the distance between the walls. These frequencies and their harmonics will cause reinforcement (or cancellation) which causes peaks (or dips) in the frequency response. Depending upon the bandwidth of these resonances, there will be energy storage and ringing at these frequencies to some extent (a great deal if the resonances are high-Q). By designing the enclosures with non-parallel walls, the wavelengths between opposite walls are different at any two adjacent points, which spreads the frequencies associated with these wavelengths and eliminates standing wave modes. The reduction in midrange distortion and frequency response anomalies is significant. In addition, the rear-wave energy from the LF driver is bounced on paths which do not immediately re-contact the diaphragm. The energy is bounced all around the interior of the enclosure, encountering damping material at each wall which absorbs much of the energy, so when it finally recontacts the diaphragm, the amount of energy is greatly reduced from the original level. This reduces the phase distortion caused by rear-wave energy creating vibrations in the diaphragm which have no relation to the current audio signal, and substantially improves transient detail performance, low-level detail retrieval, and clarity.


brucek


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## Wayne A. Pflughaupt

Hmm... As far as I know, the reason for non-parallel walls in studios has to do with reflections, not standing waves. It should be easy to find and deal with those with a program like REW.

Regards,
Wayne


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## Ethan Winer

Wayne,

> As far as I know, the reason for non-parallel walls in studios has to do with reflections, not standing waves. <

Exactly. It's common in professional control rooms for the side walls to angle outward by 30 to 35 degrees or so, which deflects all first reflections toward the back of the room. Non-parallel walls are neither good nor bad from the perspective of bass frequencies. And you can still determine "good" dimensions whether the walls are parallel or not.

That said, the biggest mistake I see people make is building a room with the corners cut off at an angle. Whether the room is parallel or not, whatever you do please leave the corners as corners! Otherwise you've just removed the single best place to put bass traps.:hissyfit:

--Ethan


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## Sonnie

Ethan Winer said:


> Whether the room is parallel or not, whatever you do please leave the corners as corners! Otherwise you've just removed the single best place to put bass traps.


What about if you cut out a big section (a wide slot of sorts) out of the cut-off corner and load it with absorbing materials, then cover it with panels? Seems like that would be a good bass trap.


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## boyce

Hi Ethan
After I did read some information from your web ( When the budget allows for dedicated construction, early reflections can be avoided by angling the side walls and sloping the ceiling upward. The control room at left was designed by noted studio designer Wes Lachot, and offers a beautiful example of such construction. Given a large enough angle - at least 35 degrees - the reflections are directed behind the listening position without having to apply absorbing materials to the walls or ceiling. This lets you better control the overall ambience in the room because you don't need additional absorption just to get rid of the reflections. But most people do not have the luxury of building new walls, so the only option is to apply absorption at key locations.)
From your professional opinion which way you will perfer?


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## Guest

Sonnie said:


> What about if you cut out a big section (a wide slot of sorts) out of the cut-off corner and load it with absorbing materials, then cover it with panels? Seems like that would be a good bass trap.



* A studio in Los Angeles did just that. It took out the entire center section of the back wall, but left the corners intact.
The trap had 8 fibercovered panels hanging from ceiling on chains at 45 degree angles (4 looking left and 4 looking right).
It was some 4 feet deep. Can't recall the width..:doh:...

Each main monitor speaker (soffit mounted) contained:
two 15" woofers and 1 HF driver. 

We needed a trap that could handle what the main monitors could put out. :yikes:

A pair of Yamaha NS-10M speakers would live on top of the mixing board. I spent more hours on those than the big main monitors.  

I actually like that room alot. It sounded 'bigger' than it really was. Thanks in part to really good room construction and room voicing.:flex:


~Bryan
*


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## Ethan Winer

Sonnie said:


> What about if you cut out a big section (a wide slot of sorts) out of the cut-off corner and load it with absorbing materials, then cover it with panels? Seems like that would be a good bass trap.


Sorry, I have no idea how I missed this post from last week! :dizzy:

Anyway, sure, that will work. The more absorption you have in a room's corners, the better. Always. Also, an opening is a perfect absorber, though what it opens to is of course a factor too.

--Ethan


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## Ethan Winer

Boyce,

> From your professional opinion which way you will perfer? <

I tend to prefer rooms more on the dead side. So if I were building a normal control room with a "normal" budget, I'd probably not bother angling the walls. However, when I built my home (well, _I_ didn't build it personally!) I specified angling the walls in my upstairs studio. I have one large room for both recording and mixing, so I did this to avoid flutter echo in the recording portion without having to put absorption all over the walls. A large room like mine (34 by 18 by 12 feet) can sound good live, and one of my goals was to be able to record classical music. If the room were smaller I'd have added more absorption, and then having angled walls would not be as useful.

--Ethan


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## Wayne A. Pflughaupt

Ethan Winer said:


> Also, an opening is a perfect absorber, though what it opens to is of course a factor too.


 No kidding? I’ve always suspected that was true, but never mentioned it for fear of being laughed off the forum! 

Regards,
Wayne


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## boyce

Ethan Winer said:


> Boyce,
> If the room were smaller I'd have added more absorption, and then having angled walls would not be as useful.


Hi Ethan

So if I have beyond normal budget for a fair side room, I should look for angle the wall right?:coocoo: 

Boyce


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## Ethan Winer

Wayne A. Pflughaupt said:


> No kidding? I’ve always suspected that was true, but never mentioned it for fear of being laughed off the forum!


In fact, the very definition of 1 Sabin is a 1 foot square opening from a room to the outside!

--Ethan


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## Ethan Winer

Boyce,

> So if I have beyond normal budget for a fair side room, I should look for angle the wall right?:coocoo: <

Sure, but understand that the "standard" angle to avoid first reflections is a minimum of 30 to 35 degrees. If you have that much extra space available, and even after angling the walls the interior room volume is still large enough to be deemed "good," it's a nice touch. However, to avoid flutter an offset of 1 inch for every linear 10 inches is enough. (Sorry, my math chops are not good enough to convert that to an angle.) See these two articles on my company's web site that explain a bit more about this:

www.realtraps.com/rfz.htm
www.realtraps.com/art_studio.htm

--Ethan


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## boyce

Thank you Ethan


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## Seb

Quinto, I am a bit concerned about what sounds like polyurethane sandwich panels. Usually, sandwich panels start off at low frequency with a good TL but then have an awfully big dip in transmisison loss at the dilatational resonance frequency of the panel (this is NOT the coincidence frequency).

These panels may suit your particular application but I would never normally use them.


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## Guest

Hi, sorry for the slow interaction...

About parallel walls: there are four reasons why I did partalell walls, the first is because of space (building walls and insulation inside a long rectangular ambient), the second is because I assumed that parallel walls make resonant modes identification a trivial job, the third is because of a ridiculous budget, the last one because I _wanted_ the common acoustic problems so to be able to solve them by means of panels we are going to build and sell there...

About polyurethane panels: I don't know their behaviour with frequencies, I'm using them as structural component. They won't behave like simple ones because we are building a rigid structure with a double layer of metal profiles (some more snapshots soon  )


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## Guest

quintosardo said:


> Hi, sorry for the slow interaction...
> 
> About parallel walls: there are four reasons why I did partalell walls, the first is because of space (building walls and insulation inside a long rectangular ambient), the second is because I assumed that parallel walls make resonant modes identification a trivial job, the third is because of a ridiculous budget, the last one because I _wanted_ the common acoustic problems so to be able to solve them by means of panels we are going to build and sell there...
> 
> About polyurethane panels: I don't know their behaviour with frequencies, I'm using them as structural component. They won't behave like simple ones because we are building a rigid structure with a double layer of metal profiles (some more snapshots soon  )



Your build sounds like a good experiment in a hybrid of studio building and product development, too. If your paneling works in your room, it'll work in others. The biggest factor in deciding to use non-parallel walls or not, is the overall size of the room - small rooms are better treated and deadened, somewhat, rather than angled alot, and bigger rooms are often better used with their inherent acoustics values intact, under carefully-planned control, rather than over-treating them. In a big room, angles influence longer mode paths, and smaller changes in the angles used, have more effect on the following returns from the more-distant opposite walls. Conversely, angles used in small rooms have to be extreme, to be of much use, in my experience.

Regards a comment made way earlier in the thread (sorry for coming late and spewing stuff... and sorry, I haven't read the whole thread, yet) about heavy building materials to control low frequencies... two thoughts, here..... one, _isolation of the space_ and, two, _customized, mathematically-calculated bass traps_ will both have better impact on those, in my opinion, that will the use of super-heavy building materials to prevent their passage. Two rules: if air can pass, or if acoustic _kinetic_ energy can pass between two areas, then so can sound, and so, _air seal_ everything you can, and _break the physical contact_ between room components, i.e., build _a room within a room_, with the floor lattice raised up on rubber blocks, and not laid directly on the subfloor (i.e., connected to the building), and with the walls of the live room framed completely away from the control room, and the whole studio, away from the rest of the building and the outside walls, plus air-sealed, as mentioned before. Then, treat the rooms with some diffusion, as needed, and with corner traps, tuned to the room's LF harmonics, to control the bottom end. If you can achieve these ideals, you will have excellent acoustics control in your rooms, in my opinion.
:yes: 

Rob Dewar,
Rock Shop Pro Audio


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## Guest

Hi, I'm back with quite a lot of material.
I've just uploaded a photo construction diary on our website, www.skstudio.it "studio" page.

Here is just one:










Some points:
- The structure is completely separated from the building.
- The acoustic control is still missing. You can see one of diffusor panels we are going to install in the control room. Bass traps will be based on resonating membranes, I agree with Ethan Winer about this. We are going to test a mixed diffusor for bass freqs: a membrane resonator with some strips of dampened Etna rock in front of it (we have a lot of Etna rock, here, you know :bigsmile: ). This should scatter basses, I'll upload measurements...
- We are going to add dampened base for drums: Etna rock sheet (again) on rubber foils...

Hope you like this diary...


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## drf

Just a note to say how much I enjoy reading this thread, it is great to see how other people deal with these issues. Every single room/venue has different accoustics and its refreshing to hear from people who obviously know what they are doing yet still ask for advice and opinions knowing that another persons perspective might be the catilyst for a better result. 

Keep it coming.


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## Guest

Hi

Im new to the forum and just found this post. I build studios for a living and if you would like some advice ill gladly help. Im curious why u would use rockwool when there is much better materials on the market. Also using drywall with lead properties helps greatly with reflection ie live rooms therefore bass traps will be a must. im using my missuses log in until i can work out how to change it.

cheers

oakesy


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## drf

What is there that is better than rockwool? is it cheaper? bigger? wider? denser? 

cheers
dr f


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## Guest

Hi

I use a product from Tontine called AcoustiSorb 3 which is a heavyweight insulation designed as an optimal product for the internal lining of walls and acoustic baffles. I also use in conjunction another product from Soundguard's premium "Flexible noise barrier", Wavebar is the easy way to reduce noise through walls, floors and buildings. As far as I am aware tontine and soundguard are international company's so if the studio builder is in italy? they could enquire there. I buy their products in the thousands of square meters hence i get it at a very reasonable price. Contact them over the net to find out. 

Also for OH&S Tontine is a far better product to handle than rockwool. I used that stuff 20 years ago for studio building, its time it was sent out to pasture!

hope that helps

oakesy


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## drf

cheers, I think it does. Now all I have to do is find a supplier in melbourne.

Looks like it might be a bit late for quintosardo as he already has bags of it delivered. Hope its not wasted.


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## Guest

The amount you can see is what remains after I've built the walls! We are going to use it for acoustical control (traps and absorbers).

Rockwool is still at its top, here. You cannot compare it to heavy materials, of course! It is a non-reflective material and that's all, but it does it well. We have to look elsewhere for insulation and weight (lead?)

Alternative materials are too expensive, here, mainly because of marketing. I looked for alternatives, here. Rockwool: 4 euro/m2, another one: 18 euro/m2. Not talking about weight, of course! Drywall+lead: 18euro/m2...

Looking at some graphs in some producers' website, they seem to end with lead in their top products... and lead corresponds to rockwool...


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