Shape of Studio

[edwinoldfield]

I am moving and am going to build a free standing studio. I am familiar with the acoustic treatment needed, but does anyone have opinions on shapes. I hear square is bad, what is ideal? I see whisper rooms seem to be pretty square, how about size also? any thoughts?

Thanks!

[FLZapped]

Actually, you are leaving out one dimension, rooms are three dimentional creatures, so you should think that way. Therefore, rather than thinking a square is bad, you should be thinking a cube is bad.....

You'll find this place to have a lot of good information:

John Sayers' Recording Studio Design Forum • Index page (http://www.johnlsayers.com/phpBB2/index.php)

One ratio set that could be used is 1:1.14:1.39 another would be 1:1:26:1:59

The idea being that each dimension would be a different length so that the room nodes do not line up. Even so, you still have three sets of parallel surfaces.

There are many other things to consider as well, so a nice long read of the above website will be of great value.

-Bruce

[edwinoldfield]

Perfect What is a great site! Thanks, Bruce

[Mike Sommer]

Are you talking about a vocal booth, or a single room studio or a studio with a booth?

For Voice Over, one only needs a single room studio. Of course it's always nice to have a machine room to keep loud equipment in and if you must have a vocal booth 5x6 would be suitable but you'll need to make it completely dead, but who wants to work in a stuffy box?

The bigger the room the better for VO booths. And avoiding a square design means just that -the fewer "right angles" you have the better. This alone will give you a head start in tuning the room by eliminating Flutter and Comb echo that you won't need to compensate for. THe design below would be a good start; the ceiling should have a slope to it also. This design is similar in size and shape to A&M Records Vocal rooms and a few others - just the treatments are different. One of the older studios I worked at here in LA, everything was covered in stone, cork, wood and plants. Not only was it a pleasure to work in it sounded wonderful.
http://i106.photobucket.com/albums/m274/disneymike/Vocal-Booth-.gif

But not everyone has this kind of room in their home for a booth of this size, but if you did, this could be used as a suitable recording and production room combo.

If you're stuck in a rectangle configuration, 15x10 with your mix position at 38% back from the 10' wall and you'll have a magical little set up. Then you can move your mic anywhere around the room especially with the set up below; a room like this can sound very good- flat with a little action in it.
http://i106.photobucket.com/albums/m274/disneymike/Studio-layout.jpg

The only thing that would make this room better are some diffusors along the back wall and above the mix desk, along with a wood floor, or possibly a soft ceiling (12" of Owens Corning 703).

[edwinoldfield]

Mike, I am not sure of the room dimensions, have only looked at them once, although funnily enough they seemed a little odd, but I will have the key in the next couple of days. It is on a very quiet street in a metropolis of 9 million people which is pretty cool and pretty hard to find something that quiet, second floor old house. What I am most concerned about is quality, I want to improve my equipment over time and this would be the start of it. It is interesting the site that Bruce gave a link too says that the space should be air tight and then you use ventilation systems. My main concern is to get the quality that is needed to compete over time with where you are (I was there at one time in a nice house at the top of Chataqua blvd, pretty nice up there in those palisades). So if it is a vocal booth, a sectioned of formed room, just as long as it creates a good recording space, that would be the great.

[Mike Sommer]

Yes, air fastness is required for 100% sound isolation. This could be nearly impossible with an older home without going to studs,replacing windows, insulating with cellulose insulation and double drywall with high density plastic sheeting in between layers, then caulking and filling every air gap and crack you can find.

So as long as you don't need to cut out a lot of background noise such as cars, barking dogs, weed whackers, foot steps or Nigle Olsson next door laying down a disco track- you should be okay with a simple isolation booth. Whisper Rooms are ok but you can often hear noise in them --they just don't offer the mass to knock out unwanted noise. I can only say, nothing beats a proper booth than a floating floor, double walls and lots of 703, and 4 layers of drywall --though some times it does not require all that, but nothing kills sound like mass and space.

Further perspective can be gained on all this here:
Studio construction & acoustics - Gearslutz.com (http://www.gearslutz.com/board/studio-construction-acoustics/)

What might be best for you is to get in there and live in it a while, and find out what the room and the neighborhood offer up first.

And as I've pointed out many times in these pages is that if you want good sound, tune your room first, 75% of your sound comes from your room. A well tuned environment is paramount for good audio. So before you haul off and and invest in a lot of gear, tune the room first. You'll be much more satisfied if you do. :afro:

[FLZapped]

The only thing that would make this room better are some defusers along the back wall and above the mix desk, along with a wood floor, or possibly a soft ceiling (12" of Owens Corning 703).


In a small room, diffusion doesn't work all that well. It's better to stick with absorption. Effects, such as reverb, can always be electronically added back in later.

-Bruce

[Mike Sommer]

**Sorry for the huge typo, I'm just banging away with my big ol' bear paws over here.

Actually diffusers are very effective in close quarters. They work so well in fact that the gang over at Skwalker Sound have diffusers, on rollers and place them around the performers. Diffusion does not add echo to a room, it breaks up or scatters the sound that strikes it and creates a very pleasant neutral sound, something you need when you've sucked all the life out of a room with 703.
http://i106.photobucket.com/albums/m274/disneymike/Skywalker_Sound_Scoring_cropped_Web.jpg http://www.gearslutz.com/board/attachments/bass-traps-acoustic-panels-foam-etc/112332d1235905743-diy-diffusors-max-20090331_ge_diffusor_05.jpg
http://www.amsterdammastering.com/includes/page-studio/imgs/3full.jpg
http://www.amsterdammastering.com/includes/page-studio/imgs/2full.jpg

The purpose for the absorption is to remove a the ringing of flutter, comb filter echos and early reflectiveness of a small hard right angled room. The bass traps remove the excess bass or Boom that's built up in the room particularly after removing all the highs. Installing diffusors will help bring a nice balance to the room --remember you still have all that all that absorption in there.

Diffusers like this, help maximize acoustical performance, by randomly dispersing sound waves to provide a consistent acoustical environment. http://www.gearslutz.com/board/attachments/bass-traps-acoustic-panels-foam-etc/112198d1235837824-diy-diffusors-max-20090228_ge_diffusor_04.jpg



Space Couplers create a natural large sound. Very nice over a mix desk in a small room.
http://cachepe.zzounds.com/media/quality,85/brand,zzounds/fit,400by400/SpaceCoupler-e3e35de8825f59cf84437457356b32c8.jpg

[FLZapped]

Once again diffusion in a small room is not that effective. It takes several wavelengths for them to create a diffuse field.

Here is another forum on just acoustics:

Acoustics Forum • Index page (http://forum.studiotips.com/index.php?sid=3d36417dfe1423f497d78018a1a8405f)

BTW - Absorption is just as effective in reducing echos, it just does it in a different manner and it is the preferred method in a small room.

The guys at Skywalker are not using their diffusers in a small room and they are using them to color the sound for the reason I stated above.

-Bruce

[edwinoldfield]

Thanks for all the information. I will post some pictures of the space when I get it in the next couple of days.

[Mike Sommer]

Once again diffusion in a small room is not that effective. It takes several wavelengths for them to create a diffuse field.

Here is another forum on just acoustics:

Acoustics Forum • Index page (http://forum.studiotips.com/index.php?sid=3d36417dfe1423f497d78018a1a8405f)

BTW - Absorption is just as effective in reducing echos, it just does it in a different manner and it is the preferred method in a small room.

The guys at Skywalker are not using their diffusers in a small room and they are using them to color the sound for the reason I stated above.

-Bruce

I think you may be a little confused here.

What I'm prescribing is exactly what you are saying USE ABSORPTION TO KILL THE "ROOM ECHOS" those would be the various types that I described: Flutter, Comb and Early Refection.
Eliminating these will make the room sound Dead, Flat or Dry and very small. But in practical matters this is not a good idea unless it is for a small booth (5'X5' and smaller) where any other effective treatment would be impractical, otherwise just get a EV RE20 or 27 and call it a day. But in a room as I've illustrated above (10x15) the effect is very practical and effective. If you note in the illustration, all the walls except one are not entirely covered with absorption panels, between the panels is bare wall, thus allowing a some refection in the room. The back wall where there is 6'' thick base trap -that would covers the entire wall floor to ceiling, that would be tuned to the room to reduce excessive boom. It is on this wall diffusion panels would be placed, and will provide a neutral, uncolored diffusion of sound that is very effective, in any space that is tuned. And that's my entire point - tuning the room.

Acoustic sound diffusion keeps sound waves from grouping, so there are no hot spots or nulls in a room. In fact, sound diffusion greatly widens the "sweet spot" and lends a strong, 3D sense of openness to a room, making it easier to hear "into" a mix. Diffusion obliterates standing waves and flutter echoes without simply removing acoustic energy from the space or greatly changing the frequency content of the sound.

Acoustic sound diffusion can make a small space seem large and a large space seem even larger. This is a good thing, and is why a the the big boys record on large stages- need I mention Disney Stage B?

Sound diffusion in a control room imparts the all-important Initial Time Delay (ITD) that keeps early reflections off room boundaries from getting to your ears too soon and smearing the direct sound you hear from your monitors. In conjunction with sound absorption, sound diffusion can effectively turn virtually any space into one that is appropriate and useful for the purpose of recording or monitoring sound with a high degree of accuracy.

A flat concrete wall with a flat smooth surface produces a pretty distinct echo when sound reflects off from it. However, a brick wall while still reflective, tends to diffuse the sound reflections and produces a much less distinct echo. This is due to both the surfaces of the brick itself and the mortar between the bricks (more specifically the edge diffraction of the joint between the two). Sound diffusion is a very important consideration in acoustics because it minimizes the coherent reflections that cause problems. Diffusion is an excellent alternative and or complement to sound absorption in acoustic treatment because it doesn’t really remove much energy, which means it can be used to effectively reduce reflections while still leaving an ambient or live sounding space. When speaking of a live sounding space I'm not referring to it sounding like the Grand Canyon, just a little action that is neutral in its resonance that will allow the voice to bloom. In the end you will have better sounding and more accurate recordings.

Another way to do this is to instal floor to ceiling bookcases and fill the shelves with knickknacks, books, plants and the like -this in fact will become a bass trap/diffuser combo. If you've ever walked into a room that is stuffed to the gills with crud by an avid collector or hoarder and listened to the sound such a room makes, you'll then know exactly what I'm referring to.

[FLZapped]

I think you may be a little confused here.

What I'm prescribing is exactly what you are saying USE ABSORPTION TO KILL THE "ROOM ECHOS" those would be the various types that I described: Flutter, Comb and Early Refection.

Yeah, you're right, I misread, sorry.

However, unless the room approaches 5000 cubic feet, diffusion just won't give you its full benefits. Setting up diffusion properly is tricky enough without having the room work against you. For the average room, absorption is far easier to make work well and is far less expensive. It can also be a great DIY project.

-Bruce

[edwinoldfield]

So here is the space. I am thinking that if I cover the walls and ceiling with fiberglass insulation and then cover it with a jute like material (as you have mentioned in another post Mike) (again what about contamination of fibre glass particles), and then use base traps along with other asorbtion techniques. On the skylight i am thinking about a double glazed window, and on then glass on the other window on the side. I really like the idea of the skylight allowing natural light in (plants, etc). The first two pictures are facing one way and the 3rd picture the other way. 4th picture shows skylight and in the middle center of ceiling.

The walls approx measure approx:
Longest wall is 13 feet,
Other long wall is 12ft 6 inches.
Width of room: thinnest point 6 ft 6 inches, middle width 7 feet 4 inches, widest 8ft 8 inches.
Height is 8 feet 9 inches to the slats.

The floor is wood with floor with tiles as seen. Underneath the wood is very solid. Do I need a false floor?

The walls are adobe type 100 year old things thick and solid, and the area is quiet.

The control room will be on the other side of a door.

Any suggestions or help on what I am thinking/should do greatly appreciated.

[Mike Sommer]

This room is perfect for a voice booth about 104 sq. feet and about 884 cubic feet. Of course you'll need to kill it dead -in terms of echo. But since it long an narrow it will be much easier to fix.

You might want to look into double doors (I like exterior jambs with curf in close-cell weatherstripping) or at least solid core doors with Pemko sweeps and ridged insulation on the jambs. You want to seal those doors like it's 40° below zero outside.

If you are going to this much expense you'll need to consider your equipment, and the kind of noise it makes. If there are any kind of fan noise or clicks you might want to consider building a small sound proof machine room/closet to keep all that stuff in, or be ready to shove it all in another room.

How wide are those exposed ceiling joist?


If you are going to make soft walls and ceiling I would look into ordering 2x8 sheets 703, you'll get a better yield from the material. Check out Rockwool too.

Check out the studio construction section over at Geatslutz you'll get a good understanding of will need to be done or can be done.
Studio construction & acoustics - Gearslutz.com (http://www.gearslutz.com/board/studio-construction-acoustics/)

Studio porn -softwalls and all.
http://i106.photobucket.com/albums/m274/disneymike/image7.jpg
http://i106.photobucket.com/albums/m274/disneymike/VO_Booth-2.jpg

[edwinoldfield]

This room is perfect for a voice booth about 104 sq. feet and about 884 cubic feet. The room will only be for voice booth, the control room will be on the other side of one of the doors.

How wide are those exposed ceiling joist? 20.25 inches

I am going to look into the corning 703 sheets and rockwool. The soft layer fiber glass insulation that they sell in rolls, is that an option?

I intend to insulate doors on both sides, double would be a little difficult.

[edwinoldfield]

What about the floor, should that be a carpet, false, or what is the best option?

Also on the skylight an double glazed pane, is that fine?

Many thanks!

[Greg Houser]

Here's a crazy question, and perhaps I missed it earlier in the thread.

For the folks asking about their rooms, has anyone taken any acoustical measurements with a microphone (as in a measurement microphone) as of yet?

It helps to know just what frequencies are more in need of taming compared to the rest of the room. Iit's more than just about the measurements of the space. The composition of the room (all six sides) and whatever else is in there will have an effect and personal experience has taught me that it pays to take a measurement microphone (you don't have to spend much for one... even the cheapies aren't bad), play some test tracks in the area and let the mic (and a good application like Room EQ Wizard) and you might be looking at things a bit differently.

I just find using a measurement microphone to determine room response a good first step when it comes to determining any changes that need to be made to the recording environment (even those which require a change in the shape of the room itself, though obviously you want to do that right the first time).

Especially for those folks who aren't using an acoustic consultant or are recording in less than ideal environments, I recommend this approach. Then again, I'm obsessive when it comes to the audio of my room.

[Mike Sommer]

Yeah Greg I was going to suggest that. It would be a good Idea to get in there and get some measurements. But I'll bet that room is full of modes and with a room that small, it's generally best to make it dead. The one thing it has going for it is that almost twice as long as it is wide and it way out of square. He may get away with just killing the ceiling one long wall and the two sides, with bass traps in each corner.

You could also build a smaller booth in that room with double walls and ceiling and a raised floor, but by the time your done with that it will have cost more than killing the room. And if you kill the room it would make a great Digital 5.1 Surround TV room.:cheesy:
~~~
No Pink Fluffy stuff. That is virtually useless in sound control.

The best sound you'll get is with a hard floor (wood) and a soft ceiling. You'll end up with maybe an area rug where you record but that's it.

For your sky light I would block in between the joist to bring those ends down, that way you can insulate right up to the skylight. I would get a pice of 1/4 or 1/2 safety glass and cover the opening with it that, this should keep any big noise out. I would also insulate the Skylights ceiling and walls as much as I can. Also caulk and seal every joint and gap.

If you really want to go the double windows, I would go with full pains with faux muttons -if you need that kind of thing. But I would still put the glass at the bottom opening.

[FLZapped]

~~~
No Pink Fluffy stuff. That is virtually useless in sound control.




This is simply not true.

As the panels get thicker, less dense material is actually better which is counter-intuitive, but acoustics is often that way.

-Bruce

[Mike Sommer]

There are only two things that kill sound: mass and distance.

That's why 703 Rockwool and high density cellulose batts trap and control sound. Look at OC's data sheets.

The fluffy batts are full of air, which is good for insulating from heat and cold, and 703 is not.

Fluffy batts will knock out some frequencies, but not the wide range we are looking for here.

[FLZapped]

There are only two things that kill sound: mass and distance.

That's why 703 Rockwool and high density cellulose batts trap and control sound. Look at OC's data sheets.

The fluffy batts are full of air, which is good for insulating from heat and cold, and 703 is not.

Fluffy batts will knock out some frequencies, but not the wide range we are looking for here.


You're wrong. R-19 has an absorption coefficient of 0.64 at 125Hz, 1.14 at 250Hz, and an NRC of 1.04. The use of faced R-19 and put the paper out and it jumps to 0.94 at 125Hz, but you loose some on the high end. Standard 2" 703 is 0.17 at 125Hz, 0.86 at 250Hz, and has an NRC of 1.0.

Even unfaced R8 is better at 125Hz, although 2" 703 exceeds it after that point, but it just shows that you cannot dismiss standard fiberglass insulation.

If you only have 2" to work with, 703 is the way to go. But if you're looking at stuffing some of those rafters, which appear to be at least 6" deep, standard insulation will work great and save you money.

-Bruce

[Mike Sommer]

Yes the fluffy stuff does control low frequency velocity, but that's all it does for the most part. My comment -though I should been more descriptive- was only addressing the confines of controlling a broad spectrum of frequencies. Where as with proper understanding of 703 or other high density materials, effective and efficient installations can be achieved.

Understanding the entire Absorption Coefficients Chart is most important.
Realize those numbers for 703 are for a 'Type "A" Mounting' -directly on the wall. With 2" of 703 with an air gap between wall, an absorption coefficient of 0.65 @ 125Hz, 1.01 @ 250Hz is achived. The larger the air space the more effective the 703 becomes at controlling bass. Mass and Distance effectively controlling low frequencies, or controlling sound by controlling its velocity.

So if he stuffs 6" of 703, with a 4" or larger air gap, he will effectively control bass build up along that ceiling, if he really wanted to go crazy stuffing the entire ceiling joist will eliminate any and all problems.

Then again bass does not tend build up along the ceiling, bass builds up in the rooms corners, which is why I recommended bass traps there. Also holding off 4" of 703, 2 to 4 inches from the wall will effectively control sound at and above low frequencies. Also a bass trap can be installed along one of the shirt walls, by building a frame 16" to 24" from wall and install 4 to 6 inches or 703. Bass in that room should be effectively controlled in that room.

All this noted without sound measurements being made or the total room dynamics understood.

[FLZapped]

Yes the fluffy stuff does control low frequency velocity, but that's all it does for the most part.

Understanding the entire Absorption Coefficients Chart is most important.
Realize those numbers for 703 are for a 'Type "A" Mounting' -directly on the wall. With 2" of 703 with an air gap between wall, an absorption coefficient of 0.65 @ 125Hz, 1.01 @ 250Hz is achived. The larger the air space the more effective the 703 becomes at controlling bass. Mass and Distance effectively controlling low frequencies, or controlling sound by controlling its velocity.

OK, so lets look at the numbers as provided by Bob Gold:

2360

So, looks like the whole mass thingy doesn't work out so well here. And it also appears as though good ol' fluffy fiberglass IS effective across a broad frequency spectrum.


-Bruce

[Mike Sommer]

That would be 6.25 inches vs 2 inches of material. Yes it would seem the denser 703 is performing better, and better yet when you compare 6 inches of 703 to 6 inches of batt fiberglass fluff.



After crunching some numbers, I will concede that the stuffing the ceiling joist with fluffy batts can and would be a real option. Now find 20" batts

[edwinoldfield]

Looking at the chart from Bob Gold. when it says in the air, versus on the wall. What does this refer to? Is that a space of 16 inches between the insulationn and the wall behind the insulation versus directly on the wall. I know leaving a space has been mentioned in this post but is it 16 inches in the chart? I know the leaving of space between the insulation and the barrier/wall behind it has been mentioned. If I understand these figures in a pedestrian way the greater the number the more the absorbtion.

[Mike Sommer]

Yes the reference is 16 inches, between the wall and fiberglass, I think the wall is plywood in the reference model.

Distance from the wall increases the the efficiencies of the lower frequencies control. What happens is, low frequencies pass through the 703, reflects off the wall and back into the 703; distance and mass controlling low frequencies. Another factor of the control of bass is the finish wall material. Walls made of gypsum are a very effective bass controller, these walls act as a sort of membrane absorber. Which leads me to the question what is the finish of your interior walls, plaster or drywall?


But understand that bass builds up in the corners, i.e. the corners where two walls come together, a floor and wall or the ceiling and wall. So for your needs, building a floor to ceiling bass trap, 6" thick, 2' wide, will effectively controlled the build up of bass. The golden-orange panels in this illustration below, show how they are set. (You can also fill the backs of these bass traps with scrap insulations for better control)

http://i106.photobucket.com/albums/m274/disneymike/Studio-layout.jpg

I also suggested building a "bass trap wall" (yellow trap in pic) along one of the short walls, six inches thick, and 16 to 20 inches from the wall. This may be total overkill but it will suck out a lot of bass. But I would not do this unless you are having real problems.


Your best bet for broad band frequency control would be to use 703 floor to ceiling, along the length of one of the long walls and the two shorter walls; Two or four inches of 703, with an air space of about two to four inches between the 703 and the wall. This will just about kill just about all the refections in this room. You will need to do something with the second long wall. Either cover the second long wall with 703 like the other -this might be best- depending the finish of this wall material, and how the room sounds. Or you can install 4" 2x4 or 2x8 panels along the wall.


Here is a fabric a lot of people use:
http://www.soundaway.com/acoustic_fabric_p/21005.htm

[FLZapped]

That would be 6.25 inches vs 2 inches of material. Yes it would seem the denser 703 is performing better, and better yet when you compare 6 inches of 703 to 6 inches of batt fiberglass fluff.

R8, which is 2.5", was also included and is is pretty close. However, the examples used were for the most commonly available materials.

There are a couple different things here that need to be differentiated.

1) Transmission loss
2) Absorption


For transmission loss, there is no doubt that using 703, or even 705, in a wall cavity is superior to regular fiberglass. Here, the mass equation works every time.

In terms of absorption, the depth of the absorber has as much effect as the material used. There is also an edge effect that comes into play which makes the absorber seem to be larger than it is. So it is possible to save some money here and use the lesser expensive fiberglass insulation.

As for modes, they all terminate in the corners, so a proper broadband corner trap will be effective for all room modes. However, it must be done right - which means it should be as big as one can possibly make it and it needs to seal against the walls and the floor and the ceiling to be maximally effective.

In the example we have here, the room is a long rectangle, so additional absorbers will be needed to control echos along the four parallel surfaces. (Don't forget the ceiling and floor) Usually about 40% coverage is all that is required.

Careful placement can not only control echos, but also help tamp down modal responses.

-Bruce

[FLZapped]

http://i106.photobucket.com/albums/m274/disneymike/Studio-layout.jpgI also suggested building a "bass trap wall" (yellow trap in pic) along one of the short walls, six inches thick, and 16 to 20 inches from the wall. This may be total overkill but it will suck out a lot of bass. But I would not do this unless you are having real problems.


This is not really needed. Another set of corner traps will be sufficient. If more traps are needed, sure add them, but covering the whole wall uses more material than needed. One can take advantage of the edge effect of individual traps which makes them seem larger than they physically are and save on material.

As for the speaker end of the room, you need to create a Reflection Free Zone (RFZ) so placement of the absorbers will need to align with the first reflection point on the walls. EDIT: Need to add, that includes the ceiling, too.

-Bruce

[FLZapped]

That would be 6.25 inches vs 2 inches of material. Yes it would seem the denser 703 is performing better, and better yet when you compare 6 inches of 703 to 6 inches of batt fiberglass fluff.

R8, which is 2.5", was also included and is is pretty close.

There are a couple different things here that need to be differentiated.

1) Transmission loss
2) Absorption


For transmission loss, there is no doubt that using 703, or even 705, in a wall cavity is superior to regular fiberglass. Here, the mass equation works every time.

In terms of absorption, the depth of the absorber has as much effect as the material used. There is also an edge effect that comes into play which makes the absorber seem to be larger than it is. So it is possible to save some money here and use the lesser expensive fiberglass insulation.

As for modes, they all terminate in the corners, so a proper broadband corner trap will be effective for all room modes. However, it must be done right - which means it should be as big as one can possibly make it and it needs to seal against the walls and the floor and the ceiling to be maximally effective.

In the example we have here, the room is a long rectangle, so additional absorbers will be needed to control echos along the four parallel surfaces. (Don't forget the ceiling and floor) Usually about 40% coverage is all that is required.

Careful placement can not only control echos, but also help tamp down modal responses.

-Bruce