The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Room within a room
Old 25th April 2019
  #1
Here for the gear
 

Room within a room

I am planning to build a small mixing room inside of an asymmetrical, larger room that is difficult to soundproof or treat. I've decided to build this room with two separate walls leaving an air gap in the middle. But, I am having doubts whether the volume (inside around 936 ft3) would yield favorable results over the cost of this project.

I assume the 2Xwall would be at least 1 ft wide in each side, so this leaves me with these maximum inside dimensions for a room.

(L,W,H)
13 X 8 X 9 ft [OR 3.96 X 2.44 X 2.74 in meters].

Is this build worth it? If so, what would be an ideal ratio for a room of this size?

Thank you in advance.
Old 25th April 2019
  #2
Lives for gear
The general guideline is around 2000 cubic feet for a critical listening room...Of course you can go smaller, but it will become progressively harder to get the room to sound good...

One thing to keep in mind is you can build the walls inside out, so you frame it on the floor, drywall it, add cavity insulation and then stand it up against the outside wall. Heavy, but wall jacks make it pretty easy...

If you go that route you can lose only a few inches in volume.

Keep in mind that you will need to do all 4 walls and either set joists for the ceiling or use hangers and channel for the ceiling-
Old 25th April 2019
  #3
Here for the gear
 

Quote:
Originally Posted by RyanC View Post

One thing to keep in mind is you can build the walls inside out, so you frame it on the floor, drywall it, add cavity insulation and then stand it up against the outside wall. Heavy, but wall jacks make it pretty easy...
Thanks for the suggestion, but unfortunately that will not be possible since we are 3 stories up.

I found that the minimum recommended volume is 2500 cubic feet. So, I'm having doubts if the cost will be justified by the results.

Also, do you happen to know which ratios might be most suitable for smaller rooms?
Old 25th April 2019
  #4
Lives for gear
 

Quote:
Thanks for the suggestion, but unfortunately that will not be possible since we are 3 stories up.
I don't understand: In your first post, you said that you planned to build walls up there, but now you say that you can't build walls up there? What changed? How come you only found out about this now?

Also, I'm not sure why being on the third floor prevents you from building walls: Did you consult with a structural engineer to arrive at that conclusion? Insufficient load-carrying capacity for the floor?

Quote:
I found that the minimum recommended volume is 2500 cubic feet.
You found wrong... The minimum recommended volume for a critical listening room (=control room) is about 1700 ft3, but that's the minimum RECOMMENDED. I have designed and built many successful rooms with much less volume than that. The smallest one to date was slightly less than 780 ft3. It's not Galaxy or Blackbird, of course, but the owner is extremely happy with it, and turning out good mixes. It is possible to build rooms with smaller than recommended volume or floor area. Certain parameters cannot be violated, but volume and area certainly can. GOing smaller means that it is much harder to treat, but it still can be done.

Download ITU BS.1116-3 and tale a look at the actual recommendations for what is required for a control room. Or EBU Tech.3276. They both tell similar stories.

But seeing that you decided that you cannot build walls in your room now, I guess it's a moot point: you will just have to live with putting some acoustic treatment around the room, but no isolation.

Pity.

- Stuart -
Old 26th April 2019
  #5
Here for the gear
 

Quote:
Originally Posted by Soundman2020 View Post
I don't understand: In your first post, you said that you planned to build walls up there, but now you say that you can't build walls up there? What changed? How come you only found out about this now?
Please excuse my lack of DIY construction knowledge. An experienced constructor (not an acoustician) will help me with the building part. I thought the previous poster suggested heavy walls (wall jacks) and using the existing walls as the outer layer. Nothing has changed, my plan is still to build a 2-walled room inside an asymmetric, brick building. However, I prefer to build 2 walls in each side without using the existing wall because I cannot go around the entire room close to the wall after leaving space for a door and a small corridor. So, my plan is to keep this new room isolated.
Weight is also an issue, so the walls cannot be too heavy. One side of the concrete floor is held by just brick walls that are not reinforced with concrete/metal beams. A consultant gave us a lot of headroom in terms of weight, but still we prefer not to put a heavy load into this room.

I thought about building two isolated wall frames standing free on layers of rubber on the tiled floor. But, we might have to mount them onto the floor if the constructor thinks it won't be structurally sound standing on its own.

It's good to know that even 780 ft3 is workable. I will look into your sources to decide a ratio. Much thanks.
Old 26th April 2019
  #6
Lives for gear
 

Quote:
I thought the previous poster suggested heavy walls (wall jacks) and using the existing walls as the outer layer.
What Ryan suggested was building your walls "inside out", instead of "conventionally". That's a technique that can save space, if done carefully. Basically, when built "inside out", the inner-leaf wall of your studio ends up with the bare studs facing the room, and the drywall facing the cavity inside the wall. A normal wall would be the other way around: the studs facing the cavity, and the drywall facing the room. "Inside out" is a good technique, and can save space, as it allows you to build a lot of your acoustic treatment into the wall itself (between the studs), rather than sticking out on top of the surface. It is especially useful for ceilings, as it can gain you lots of height acoustically: you can get back nearly the full depth of your inner-leaf ceiling joists, which could be many inches, depending on what distance your ceiling has to span.

The problem with "inside out" walls that Ryan was pointing out, is that they have to be built laying down flat on the floor, then raised into position vertically, and that's not easy to do because they are heavy. But they are NOT heavier than any other wall: in fact, an inside-out wall would be the exact same weight as a "conventional" wall: same studs, same drywall, same insulation. No difference in weight. The only difference is in the technique itself, and generally you need to use wall jacks to raise an inside-out wall. Wall jacks are actually very common in house construction, and you can probably rent them for a couple of days, or just buy them on e-bay and re-sell them when you are done. There's some photos below showing what they look like and how they work.

Quote:
my plan is still to build a 2-walled room inside an asymmetric, brick building.
That sounds like you are planning to build a 3-leaf wall... not a good idea if you want low frequency isolation. All other factors being equal, a three leaf wall system will always perform WORSE than the equivalent two leaf wall for low frequency isolation (same total weight, same materials, same total thickness). You can compensate for the lost isolation by increasing the total mass by at least 50%, or increasing the total thickness of the wall system by 50%, or both, but that wastes a lot of space, and/or costs a lot more to build. It also weighs more, and you say you have to be careful with your total weight, for structural reasons....

It would be better to do what Ryan suggested: Use the existing building shell as your outer leaf (it does not matter if it is not symmetrical, and that can even be beneficial, as long as the inner-leaf is symmetrical), then build your inner-leaf within that. That's the true meaning of "room within a room" construction. It means that you have only two leaves in total: the outer leaf (usually the building itself), and the inner-leaf (that gives the actual shape and size to the room itself). If the building shell is much larger than the final inner-leaf studio will be, then you can use a corner of the original building as the outer leaf, and build an extension of that around the other two sides, then build your inner-leaf within that.

That's the common way of building studios.

Quote:
I thought about building two isolated wall frames standing free on layers of rubber on the tiled floor.
Apart from being unsafe and not necessary, that is probably also illegal, or at least not approved by code. Where I live, it is illegal to have internal walls not attached to the floor, for seismic reasons: even a small quake, such as a magnitude 4 or 5, would cause major damage to such a wall, as it would skid around on top of the floor. I would never design or build a studio where the walls are not firmly bolted into the floor.

The rubber does nothing for you. Floating a wall is way harder than just throwing any old piece of rubber under the sole plate... Lots of calculations involved in getting that right, and very likely not necessary at all. Unless you are floating your floor as well, which is an even bigger endevour!

Quote:
if the constructor thinks it won't be structurally sound standing on its own.
The constructor has no say in the matter! Only the law can guide you there. Your applicable building codes will define what is and what is not allowable. Your structural engineer (NOT the architect, and NOT the contractor) might want additional precautions or restrictions, applicable to your specific case, but will never recommend something LESS that what code allows.

Quote:
It's good to know that even 780 ft3 is workable.
That's minimal, yes, but I would not recommend trying to do anything that small, unless you hire a studio designer to design it for you. It is really, really hard to do such a small room. The bigger the room, the easier it is to treat. If you can get something like 220 square feet and 2000 cubic feet, that's not too hard at all to treat, and you can get really good results like that. Smaller is hard, and less than about 150 square feet / 1300 cubic feet, you start sacrificing acoustic conditions. If this is your first studio, then don't go small. Make it as big as you possibly can, in both area and volume.


- Stuart -
Attached Thumbnails
Room within a room-wall-jack-001-sml.jpg   Room within a room-wall-jack-002-.jpg   Room within a room-wall-jack-003-sml.jpg   Room within a room-wall-jack-004-sml.jpg  
Old 26th April 2019
  #7
Lives for gear
Quote:
Originally Posted by mtsyas View Post
I am planning to build a small mixing room inside of an asymmetrical, larger room that is difficult to soundproof or treat.
Probably the best bet is to take a step back and analyze your goals vs your budget here...

Have you determined how much more isolation you need? Do you have access to the rooms below you in the building for testing?

It seems a little unclear here what your plan is, but think of a room in a room as like a shed, or a garage, built inside another building. Anything that doesn't have 4 walls and ceiling like a shed or garage isn't a room in a room.

Maybe a better term for it is a small building inside a building.

If you want to frame out walls for the purpose of holding insulation as treatment, sure, just leave out the drywall. It won't do anything for you isolation wise either way. But if that can give you a treatment surface that is symmetrical that could be a good start. Just don't expect any soundproofing...

On the 3rd floor, any serious attempt at soundproofing is likely to be very heavy (IE pouring concrete on spring isolators) and very expensive.
Old 26th April 2019
  #8
Here for the gear
 

Stuart, thanks for your explanation, and also Ryan. To answer you both why I intend to make this build the way I'm trying to explain is because I think,

1. leaving two air gaps will improve sound-proofing. These two gaps are the small cavity between the 2 new (wood) walls and the larger gap between this two-walled room and the existing room.
2. the new room can be built symmetrically, isolated from the oddly shaped existing room that also bring in a lot of noise through the ceiling and the single pane large windows.
3. since there are two walls, I can apply insulation material to both these wall frames, which also have that air gap between these 2 insulation layers. I assume this will help with sound-proofing 2X more- or not as effective as I assume?

I was thinking of adding only a plywood layer to the inside of the control room (inner-most wall). Bad idea?

I haven't really given much thought to the ceiling of this new room.

This is my first studio build, and unfortunately, this is the only room of a decent size I have access to at the moment.

Quote:
Originally Posted by RyanC View Post

Have you determined how much more isolation you need? Do you have access to the rooms below you in the building for testing?
This is in a house. And all the spaces in the lower levels have open areas, i.e. no room with four walls around it in the two lower floors.
Old 26th April 2019
  #9
Gear Head
 

Regarding sound proofing, there’s a number of great videos on YouTube that cover this. They mention using stuff like 2 sheets of 5/8” dry wall, green acoustic glue, fiber glass intulalting. All very interesting as I’m looking into building a soundproof rehearsal room in our garage. There’s really so much more to consider than I ever expected when it comes to sound remediation. And that’s not even considering the treatment required for a control room.

What does the term two leaf and three leaf pertain to? And why is three leaf worse for low frequency?

Following this thread with curiosity as I prepare for my project soon

Cheers
Old 26th April 2019
  #10
Lives for gear
 

Quote:
1. leaving two air gaps will improve sound-proofing.
Actaully, no it will not. You probably should do some research on the "three-leaf problem". More on that below.

Quote:
2. the new room can be built symmetrically, isolated from the oddly shaped existing room that also bring in a lot of noise through the ceiling and the single pane large windows.
As I said, an asyemmtrical outer shell with a symmetrical inner-leaf can work quite well. Take a look at Phillip Newell's books and studios to find out more. He does that regularly.

Quote:
3. since there are two walls, I can apply insulation material to both these wall frames, which also have that air gap between these 2 insulation layers. I assume this will help with sound-proofing 2X more- or not as effective as I assume?
Insulation in the wall cavity is fundamental to how MSM-based isolation works. The insulation by itself does nothing at all. Each leaf by itself doesn't o a lot either, since it is limited by Mass Law. But the combination of two leaves, decoupled from each other, with insulation in between, is pretty amazing. Because resonance. The whole is greater than the sum of its parts. If you leave out any of those four things (two leaves of substantial mass, decoupling, sealed air cavity, insulation damping), then you lose the entire system. It's the exact same principle as the suspension system in your car: If you leave of the wheel, or the spring, or the shock absorber, or the chassis, then you get a terrible ride. Put all of them in place, properly arranged, and you get good "isolation" from the road surface.

That's the long answer, to say that yes, you do need to fill the entire air cavity between your two leaves with suitable insulation. Leaving that out would cost you between 10 and 16 dB of isolation. Which is a LOT!

All this works because a two-leaf wall is a resonant system that has one single air cavity, with one single fundamental resonant frequency, that you can tune well below the audible range, and thus get good isolation across the entire range.

No, having three leaves instead of two does not improve isolation. That's not intuitive, I know, but it is true. Adding a third leaf to that potentially REDUCES isolation in low frequencies, all other factors being equal. Because you now have two air cavities, and two resonant frequencies, both of which are higher than the single frequency you would have got with a 2-leaf wall. Since isolation only really gets useful at twice the resonant frequency, you get worse isolation in the lows from a 3-leaf, as compared to a 2-leaf with the same parameters.

As I mentioned, if you have no choice, and are forced to create a 3-leaf system, then it is possible to compensate for that by tuning both of those resonant frequencies down below the bottom of the audible spectrum again, but to do that you have to add a lot more mass (mostly to the middle leaf), and increase the sizes of both air gaps, or both.

Below is a simple diagram that shows how this works. The situation on the left is a 4-leaf wall, which is the worst case. There are two stud frame, each with a single leaf of drywall on BOTH sides, and insulation in two of the three air gaps. The isolation in that case is STC-44. The middle diagram shows what happens if you TAKE OUT one of those inner sheets of drywall: now you have a 3-leaf system. And even though it has LESS mass now, it still isolates nearly twice as well (about 10 points better). The diagram on the right is the best-case: That's a 2-leaf wall now, where the two inner sheets of drywall have both been moved to the outsides of the studs. That ha improved the isolation yet again, by another ten points, to STC-63. So it is twice as good (subjectively) as the 3-leaf system, and FOUR TIMES as good as the four leaf. Yet it contains exactly the same materials, and is exactly the same total thickness.

What we are suggesting is that you should build your studio as in the diagram on the right. What you are saying is that you want to build it like the diagram in the middle. If you did, you would only get HALF the amount of isolation (subjectively: 10 points less objectively). In other words, your method would block only one-tenth of the energy blocked by the one on the right.

Quote:
I was thinking of adding only a plywood layer to the inside of the control room (inner-most wall). Bad idea
Depending on how much isolation you need, that probably isn't enough. You could use plywood, but OSB is higher density and usually about the same price. I usually put one layer of 5/8" or 3/4" OSB on the studs, then a layer of 5/8" drywall on top of that. If I need better isolation, I out Green Glue Compound between the OSB and the drywall.

Quote:
I haven't really given much thought to the ceiling of this new room.
The ceiling has to be done the same way as the walls, or you get no isolation at all! Sound moves equally in all three directions, so if you have fantastic walls but a weak ceiling, then sound will just take the easy path out, through the ceiling, totally bypassing your walls. The same applies to your windows, doors, HVAC system, and electrical system. All of then must be designed for the same level of isolation, because your total isolation is only as good as the weakest part. So if you have three-leaf walls, you will also need a three-leaf ceiling...

Quote:
and unfortunately, this is the only room of a decent size I have access to at the moment.
The size is not ideal, but workable. However, your concept of using triple-leaf walls is wasting a lot of space. The second image below shows how your situation is typically handles for studios, if you don't want to use all of the available area, but do need a two-leaf system.

- Stuart -
Attached Thumbnails
Room within a room-2-leaf-3-leaf-4-leaf-stc-diagram-classic-enh.gif   Room within a room-msm-two-leaf-wallchunk-conventional-not-inside-out-one-room-s06.png  
Old 26th April 2019
  #11
Lives for gear
 

Quote:
Originally Posted by DJElectricDaddy View Post
There’s really so much more to consider than I ever expected when it comes to sound remediation. And that’s not even considering the treatment required for a control room.
Right! Acoustics is a huge subject, and much of it is not even intuitive. Such as the 2-leaf / 3-leaf thing, for example. Or the fact that lower density insulation is better for low frequencies than high density insulation... The problem is, our brains are very visual, but we can't see sound, so we make assumptions about how it should behave based on things we can see, and those assumptions are often wrong.

Quote:
What does the term two leaf and three leaf pertain to? And why is three leaf worse for low frequency?
I think I covered that above, in basic outline, but here's the more technical details:

With a single leaf wall (eg, concrete, or brick, or a stud frame with sheathing on only one side such as an unfinished garage), you are subject to a principle of physics called "Mass Law", which is not very exciting. In simple terms, Mass Law says that each time you DOUBLE the total mass of the wall, you get an increase of only 6 dB in isolation. That's in the perfect world of theory, but in the real world, it is more like 5 dB each time you double the mass. The full Mass Law equation is:

TL(dB)= 20log(M) + 20log(f) -47.2

Where:
M is the surface density of the panel (mass per unit area (kg/m²) ), and
F is the center frequency of the third-octave measurement band

With a single-leaf wall, you need HUGE amounts of mass to get good isolation. Many, many inches of solid concrete.

With a two-leaf system (such as the right-hand wall in the image above with the three different constructions), you have Mass Law applying to each leaf, but you cannot just add the two together to get the total. So if each leaf by itself would have given you 30 dB of isolation, you can's assume that both together will give you 60 dB of isolation, because now there's another factor in play: resonance. The air in the gap between the walls acts like a spring that joins together the two "masses" of the two individual leaves, and together they form a resonant system. When the pressure of an approaching sound wave forces the drywall on one side to bend in a little, that slightly compresses the air "spring" inside the wall, which then "fights back": the higher pressure tries to push the drywall out again, but that's delayed a little in time because the moving drywall has inertia, and if that "outward push" happens to occur at the same time as the arriving sound wave is now trying to suck the drywall out as well, then things are perfectly synchronized, and you get resonance: each pressure front of the wave pushes the wall in, and inertia keeps it going in a bit more (because: mass), then just as the air spring manages to push it back out again the wave rarefaction is also doing the same thing from the other side, pulling it out... until the next pressure peak arrives, pushing it in... but once again the drywall overshoots due to inertia= delay in time= frequency..., and you have a wonderful situation: the drywall is singing along loudly with your sound wave! And because the entire cavity is resonating, the drywall on the other side also wants to play along as well, because it too is now subject to the same pressures and rarefactions going on inside the cavity. ZIIINGGGGGG!!!! So you have the fantastic situation where the entire wall is humming along with that specific tone, at the resonant frequency of the wall, and transmitting it through to the other side... Not so good. But it only does that for one specific tone.... Not for any other...

However, if you tune your wall so that the resonant frequency where the above happens, is far below the bottom end of the audible spectrum, then you that situation will never happen: the incoming sound waves will still cause the drywall to push inwards, compressing the spring, which pushes back, sure: no problem. But since the timing will be off, the wave on the outside won't be "sucking out" at the same time as the spring is pushing out: in fact, it might be pushing back in again at that point, then trying to "suck out" during the inertial overshoot when the drywall is already heading back in... so there is no resonance, and the wall isolates.

So a two-leaf system gets you better isolation than a single-leaf system... except at resonance. Thus you need to tune it so that it does not resonate in the audible spectrum. Technically, you need to keep the resonant frequency at least 1.414 times lower than the lowest frequency you want to isolate, but it's easier just say "twice as low". For complex mathematical reasons, at exactly 1.414 times the resonant frequency the wall neither isolates no resonates. At twice the resonant frequency, it is isolating decently. And it improves from there, all the way up (or at least, up to the point of the coincidence dip, but that's another story... ).

You tune your wall by adjusting the mass on each leaf (surface density) and the depth of the air gap between the leaves. The equation for two-leaf resonance is fairly simple:

f0 = C [ (m1 + m2) / (m1 x m2 x d)]^0.5

Where:
C=constant (60 if the cavity is empty, 43 if you fill it with suitable insulation)
m1=mass of first leaf (kg/m^2 or lbs/ft2)
m2 mass of second leaf (kg/m^2 or lbs/ft2)
d=depth of cavity (m or ft)

(C=43 for imperial, 1897 for metric)

That gives you the resonant frequency. To figure out the isolation, you need some more equations:

For a two-leaf wall, you need to calculate the above for EACH leaf separately (call the results "R1" and "R2").

Then you need to know the resonant frequency of the system, using the MSM resonance equation above. Then you use the following three equations to determine the isolation that your wall will provide for each of the three frequency ranges:

R = 20log(f * (m1 + m2) ) - 47 ...[for the region where f < f0]
R = (R1 + R2)/2 + 20log(f * d) - 29 ...[for the region where f0 < f < f1]
R = R1 + R2 + 6 ...[for the region where f > f1]

Where:
m1 and m2 are the surface densities of leaf 1 and leaf 2, respectively
f0 is the resonant frequency from the MSM resonant equation,
f1 is 55/d Hz
R1 and R2 are the transmission loss numbers you calculated first, using the mass law equation

And that's it! Nothing complex. Any high school student can do that. It's just simple addition, subtraction, multiplication, division, square roots, and logarithms.

That's a very simplified explanation, and a very simplified form of the equations: In reality, there's more things to take into account if you want an accurate prediction for the complete spectrum (coincidence dip, for example...).

Now, for a three-leaf system, it gets more complex, because you now have TWO resonant systems acting together, and the resonant frequencies are usually called f+ and f-, or fa and fb, and they will BOTH be higher than the f0 of the equivalent two-leaf wall. Thus, to get good isolation, once again you have to get BOTH of those resonances down below 1.414... and since they were already HIGHER than for the two leaf, you need MORE mass and a BIGGER air gap. It is possible, yes, but it costs a lot more money, and takes up more space: That's why 2-leaf is the best system. It maximizes isolation while minimizing use of materials, space, and cost.

Here's the equations for a 3-leaf system:

- Stuart -

EDITED: to add the second image below, which shows the situation very clearly, in graphic form. You can clearly see how the isolation improves for the high end, but gets a lot worse for the low end. Take into account that the "single leaf" here is a massively thick (400mm, = 16") concrete wall, and the other two are simple stud frames with drywall, in a thinner profile (290mm = +/-11"). You can see that the two-leaf gets nearly as good as the concrete (even though it is just one twentieth the mass and only two-thirds as thick!) except for the coincidence dip (around 2 kHz), while the 3-leaf is terrible in the low end even though it has 50% more mass than the two leaf!!

Conclusion: 1 leaf bad, 2 leaf good, 3 leaf bad.

Not intuitive at all...
Attached Thumbnails
Room within a room-3-leaf-msm-resonance-equation.jpg   Room within a room-tl-graph-isolation-single-double-triple-1-2-3-leaf-walls-sml.jpg  

Last edited by Soundman2020; 26th April 2019 at 07:40 PM..
Old 26th April 2019
  #12
Lives for gear
Quote:
Originally Posted by mtsyas View Post

This is my first studio build, and unfortunately, this is the only room of a decent size I have access to at the moment.



This is in a house. And all the spaces in the lower levels have open areas, i.e. no room with four walls around it in the two lower floors.
Patience and caution young Jedi, as once you embark down the dark path there is no turning back ! And there is a long strewn out graveyard of tortured, departed souls who spent out all of their energy (and $money) on failed attempts, only to get nowhere and shrivel up into dried out corpses before their time !!
Old 27th April 2019
  #13
Here for the gear
 

Stuart, thanks for your detailed messages. There's a lot to learn here, especially in the principles that are counterintuitive. I will do research on the pointers you brought up and come up with my design within a week. If I go through this project, I will share the process, images and measurements at this thread. Cheers!
Old 29th April 2019
  #14
Here for the gear
 

Quote:
Originally Posted by Soundman2020 View Post

Download ITU BS.1116-3 and tale a look at the actual recommendations for what is required for a control room. Or EBU Tech.3276. They both tell similar stories.
I have a question about dimensions since now I have an opportunity to rent a slightly bigger and better room (rectangular with a concrete ceiling).

Those two references given to me above suggest that the dimensions should satisfy the following ratios in order "to ensure a reasonably uniform distribution of the low–frequency eigentones."

1.1w/h =< l/h =< 4.5w/h - 4

This room's dimensions are 9'4" (h), 10'3" and 13'. I decided to build it (if I go with this room) under a recommended ratio of 1 : 1.14 : 1.39 by ModeCalc. So, the dimensions would be 9'(h), 10'3", 12'6". However, this doesn't satisfy the above recommendation unless I increase the width, which is not possible.

Which should I give priority to? And, is there ratio better suited for a room of this size?
Old 11th May 2019
  #15
Gear Head
 

Quote:
Soundman
Wow. Such a fully detailed post. Thanks much. I know I will have to read and digest that many times before I fully grok the finer points. I consider myself well schooled

Cheers
Old 13th May 2019
  #16
Not trying to derail the thread, but if I am reading correctly, a ceiling of 120" with a ratio (provided by DanDan on another thread) of 1, 1.28, 1.54, would give a total of 1971.2 cubic feet (10'x12.8'x15.4'). Would that be a good room size for a control room?
Old 13th May 2019
  #17
Lives for gear
 

Quote:
Originally Posted by CurseesConnect View Post
Not trying to derail the thread, but if I am reading correctly, a ceiling of 120" with a ratio (provided by DanDan on another thread) of 1, 1.28, 1.54, would give a total of 1971.2 cubic feet (10'x12.8'x15.4'). Would that be a good room size for a control room?
Yes it would. That would be a good sized room, with a good ratio. If you can make it bigger, that would be even better.

- Stuart -
Old 16th May 2019
  #18
Here for the gear
 

I am currently building my studio in a new room I recently acquired. It's at least symmetrical (for a control room) and will be finished nearly to the centimeter of 1 : 1.14 : 1.39. My biggest fear is that it may not have enough volume according to all sources/recommendations I found and the Genelec 8050Bs I own may not be suitable for it. It's 36 m3 or 1271 ft3. I am planning to rely more on diffusion rather than absorption as treatment.

Has anyone "successfully" treated such a small room even with the advantage of a ratio? I define "successfully" as capable of turning out professional mixes.
Old 16th May 2019
  #19
Lives for gear
Some great pots by Stuart...again!

Quote:
Originally Posted by Soundman2020 View Post
The whole is greater than the sum of its parts.
Old 16th May 2019
  #20
Lives for gear
 

Quote:
Originally Posted by mtsyas View Post
I am currently building my studio in a new room I recently acquired. It's at least symmetrical (for a control room) and will be finished nearly to the centimeter of 1 : 1.14 : 1.39. My biggest fear is that it may not have enough volume according to all sources/recommendations I found and the Genelec 8050Bs I own may not be suitable for it. It's 36 m3 or 1271 ft3. I am planning to rely more on diffusion rather than absorption as treatment.

Has anyone "successfully" treated such a small room even with the advantage of a ratio? I define "successfully" as capable of turning out professional mixes.
There's no need to go crazy over room ratios. They are just one of many factors that you should consider when designing your studio. As long as your ratio is not close to the "bad" ones, and reasonably close to the "good" ones, that's all you really need to worry about.

For a small room, maximizing the volume is more important than hitting a ratio "to the centimeter". If getting the ratio right means that you have to make the room smaller than it would be otherwise, then forget the ratio and just make it as big as you can. The commonly-quote specs for control rooms list a floor area of 20m2 as the "minimum" area, and allowing for a decent ceiling height, that gives a volume of about 50 m3. That does not mean that a smaller room will be terrible! It just means it will be harder to treat.

There's no problem with your speakers, by the way. They are fine. Even small rooms need good speakers.

- Stuart -
Old 16th May 2019
  #21
Here for the gear
 

Quote:
Originally Posted by Soundman2020 View Post
There's no need to go crazy over room ratios. They are just one of many factors that you should consider when designing your studio. As long as your ratio is not close to the "bad" ones, and reasonably close to the "good" ones, that's all you really need to worry about.

For a small room, maximizing the volume is more important than hitting a ratio "to the centimeter". If getting the ratio right means that you have to make the room smaller than it would be otherwise, then forget the ratio and just make it as big as you can. The commonly-quote specs for control rooms list a floor area of 20m2 as the "minimum" area, and allowing for a decent ceiling height, that gives a volume of about 50 m3. That does not mean that a smaller room will be terrible! It just means it will be harder to treat.

There's no problem with your speakers, by the way. They are fine. Even small rooms need good speakers.

- Stuart -
Thanks for your post again Stuart.

I am not making the room smaller to get the ratio- it just happens that the width and the height already has that ratio while the height was 1 cm higher leaving just enough room for a carpet on the tiled floor. Since it's brick and concrete, it doesn't need extra isolation for my needs. I made a two-leaf decoupled dual wall at the back of the room to get the entrance somewhat towards the middle so there's space for bass traps and it leaves about a 1.5 feet corridor at the back of the room that I will use as a server room. So, no space is wasted on getting this ratio.

These speakers go down to 32 Hz and I wonder if it will create untreatable issues in this small space.
Old 16th May 2019
  #22
Lives for gear
 

Quote:
Originally Posted by mtsyas View Post
I am not making the room smaller to get the ratio- it just happens that the width and the height already has that ratio while the height was 1 cm higher leaving just enough room for a carpet on the tiled floor.
OK, understood on the ratio: you got lucky! That's great.

However... :
Quote:
just enough room for a carpet on the tiled floor.
Carpet!!!
Nope. Bad idea for a studio! Carpet does the exact opposite of what small rooms need. Forget the carpet, and stick with the tiled floor.

Quote:
These speakers go down to 32 Hz and I wonder if it will create untreatable issues in this small space.
Room size does not dictate what speakers you need. Your music dictates what speakers you need. If you have no need to mix bass guitar, piano, keyboards, roaring electric guitars, and electronic instruments, then it's fine to dump those great speakers and buy some cheap 4" bookshelf things.... But if you do want to mix those instruments, then you better keep them, and if you need to mix really deep bass for clubs, or maybe effects for movies (earthquakes, canon fire, rumbling engines, thunder, etc.) then maybe you should even add a sub to get down really low.

This argument comes up from time to time, about "my speakers are too big for my room", but that's never actually true (unless maybe they are physically too large to install comfortably). Speakers need to cover the range of frequencies that you need to mix, with some extra margin at each end, full stop. That's it. Nothing more, nothing less. The room does not come into the equation. You have to be able to hear everything that you need to mix, and if your speakers do not go down low enough to allow you to hear all of then your mixes will not translate. It's very simple, actually: If you can't hear it, you can't mix it! But other people listening to your mixes later on bigger speakers, will then hear the stuff that you didn't hear, and that you didn't mix...

The only thing you need to worry about with your room in regards to speakers, is treating it properly for whatever speakers you have. Treat the room properly, and you can use whatever speakers you want, or more correctly, whatever speakers you need.


- Stuart -
Old 4 weeks ago
  #23
Here for the gear
 

Quote:
Originally Posted by Soundman2020 View Post

Room size does not dictate what speakers you need...This argument comes up from time to time, about "my speakers are too big for my room", but that's never actually true.
This is my view too based on my academic background in psycho-acoustics / music perception & cognition. But due to my lack of practical music mixing experience, I have given in to those common ideas such as "each waveform needs space to develop fully in order for you to monitor it accurately" because I see them time and again. Our brains are well adapted to putting things in order even when information is missing (think of the missing fundamental phenomenon), and it's certainly capable of identifying a low frequency from a segment of a waveform. Otherwise, a subject would not perceive/intuit a low frequency in a small anechoic chamber, or will not the same through high-end headphones. It is certainly a different sound when you perceive 35 Hz through a decent pair of headphones or a small room with late reflections or a mastering room of recommended size. It is hard to define the "clarity" of low frequencies in the first and the third experiences stated in the previous sentence based on my experience, but my challenge is to find out if I can achieve a "shade of clarity" in my small room. This will be a series of experiments I will be attempting in the next few weeks.
Thanks for your responses Stuart. I just read your REW tutorial in a different site and will be using that as a guideline in my initial testing.
Old 4 weeks ago
  #24
Lives for gear
 

Quote:
Originally Posted by mtsyas View Post
...But due to my lack of practical music mixing experience, I have given in to those common ideas such as "each waveform needs space to develop fully in order for you to monitor it accurately" because I see them time and again.
I have seen that myth expounded many times, all over the place, but there is just no truth at all to it. There's a very simple proof to show that it is plain wrong: Can you hear deep bass on your car stereo? Sure you can! Despite the very tiny dimensions of a car interior, with no hope of "space for the waveform to develop", you can indeed hear wonderful drum solos and bass guitar, and even cathedral pipe organs, way down in the low 40, 30, and 20 Hz range... assuming you have the speakers in your car capable of producing such tones... Even though your ears are just a couple of feet from the speakers, and even though they are producing waves dozens of feet long, you can still hear them very well.

There's an even simpler proof that the myth is pure garbage: Can you hear deep bass when you listen on your iPhone earbuds? Sure you can! Even though your eardrums are just millimeters away from the speaker, with no chance in hell of any sort of "waveform developing", not even the very highest frequencies, you can still hear the sound rather well.

So scratch that one off your "things I gave into despite my correct understanding of the principles of acoustics and psycho-acoustics".

The only slight truth to that "space to develop the waveform" is when you have a 2-way, 3-way, o whatever-way speaker, with different drivers producing different frequency ranges. You do indeed need a little distance for the individual sounds from the individual drivers to merge into one coherent sound field, but that's a simply physical issue, not an acoustic issue: the drivers are separated laterally in space, that's all. This does not apply to coaxial speakers, for example. But this issue has nothing to do with the mythical ability of a room to "form the wave": it's simply allowing enough distance between the speaker and your ears to perceive the individual drivers as one single source.

Quote:
Our brains are well adapted to putting things in order even when information is missing (think of the missing fundamental phenomenon), and it's certainly capable of identifying a low frequency from a segment of a waveform.
Only if the waveform is sufficiently complete: You can't tell what the frequency or intensity of a wave is, from just 1/8th of the cycle... You need a couple of cycles to be able to do that.

Quote:
Otherwise, a subject would not perceive/intuit a low frequency in a small anechoic chamber, or will not the same through high-end headphones. It is certainly a different sound when you perceive 35 Hz through a decent pair of headphones or a small room with late reflections or a mastering room of recommended size.
That's partially due to a different phenomena: Low frequency sound is perceived not just with the ears, but with the entire body if it is loud enough, or even with just the chest cavity at lower levels. You also have no ability to determine directionality of sounds on headphones, which you do when listening to speakers, because of the HRTF. That's why, when you listen on headphones, your brain tells you that the sound is localized inside your head, and the sound stage only covers the space between your ears. With speakers, your brain tells you that the sound comes from outside your head, and is located around you, spread across the space between the speakers (or even wider, depending on room acoustics). There are a couple of methods for "faking" sounds to appear slightly outside your head on headphones, using techniques like Ambisonics, which attempt to fool the brain into doing that by carefully crafting the sound at each ear to put back some of the clues that would have been there if you were listening on speakers, but that's not what we are talking about here: normally recorded music mixed normally in a studio control room setting.

Quote:
It is hard to define the "clarity" of low frequencies in the first and the third experiences stated in the previous sentence based on my experience, but my challenge is to find out if I can achieve a "shade of clarity" in my small room.
You most certainly can! That's what good room design and treatment is all about! Once you hear the clarity and "tightness" of bass in a good room with good speakers, you'll never want to go back to mixing any other way! But you cannot achieve that with speakers that don't actually produce the frequencies that are in the music. The sound actually has to be there, in order for the room to do anything with it. If your speakers don't go low enough, you won't get the clarity, tightness, and "punch" that you need in order to mix. And once again: If you can't hear it, you can't mix it. But others will still hear it... and they will hear what you did not hear, and did not mix...

Imagine telling an artist to paint a sunset scene, but then not giving him any red, yellow or orange colors on his palette, only greens and blues... If he's really good, he might be able to paint an impression of a sunset, so you can understand what he's trying to get across, but it still won't look like a real sunset.

Getting the low end right when designing control rooms is where I spend a LOT of time in the design stage, then again in the final room-tuning stage. It's not that hard to do, as long as you follow the principles of both acoustics and psycho-acoustics.

Quote:
This will be a series of experiments I will be attempting in the next few weeks.
Experiment by all means, but it really isn't necessary: as you know from your own studies of psycho-acoustics, the mechanisms of our ears and brain are quite well understood, so there's not really much need to "re-invent the wheel". The principles of what a studio needs in order to be usable are fairly well laid out already, in documents such as ITU BS.1116-3 and EBU Tech.3276, among others. They cover the practical specifications of what the speaker response, speaker layout, and acoustic response needs to be in a critical listening room. If you want the theory behind that, I'd suggest Floyd Toole's "Sound Reproduction" and also Kleiner and Tichy's "Acoustics of Small Rooms". Although I suspect you might have already read those!


Quote:
Thanks for your responses Stuart. I just read your REW tutorial in a different site and will be using that as a guideline in my initial testing.
Post the MDAT's here, or over there, and I'll try to take a look at them if I have a moment.

- Stuart -

Last edited by Soundman2020; 4 weeks ago at 05:31 AM.. Reason: EDITED: to fix schpellink errrorz
Old 4 weeks ago
  #25
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by mtsyas View Post
This is my view too based on my academic background in psycho-acoustics / music perception & cognition. But due to my lack of practical music mixing experience, I have given in to those common ideas such as "each waveform needs space to develop fully in order for you to monitor it accurately" because I see them time and again. Our brains are well adapted to putting things in order even when information is missing (think of the missing fundamental phenomenon), and it's certainly capable of identifying a low frequency from a segment of a waveform. Otherwise, a subject would not perceive/intuit a low frequency in a small anechoic chamber, or will not the same through high-end headphones. It is certainly a different sound when you perceive 35 Hz through a decent pair of headphones or a small room with late reflections or a mastering roomg.
What is your point? Well designed/treated are much better than random rooms. You can even build identical sounding rooms with Boggy's MyRoom and Newell's design.

I do not know what music you do but Bach's Fugue in D minor, Richard Strauss' Also Sprach Zarathustra, the final movement of Saint-Sains' Organ Symphomy and moderm EDM music. All contain passages of significamt no harmonic bass.
Old 4 weeks ago
  #26
Quote:
Originally Posted by DJElectricDaddy View Post
Regarding sound proofing, there’s a number of great videos on YouTube that cover this. They mention using stuff like 2 sheets of 5/8” dry wall, green acoustic glue, fiber glass intulalting. All very interesting as I’m looking into building a soundproof rehearsal room in our garage. There’s really so much more to consider than I ever expected when it comes to sound remediation. And that’s not even considering the treatment required for a control room.

What does the term two leaf and three leaf pertain to? And why is three leaf worse for low frequency?

Following this thread with curiosity as I prepare for my project soon

Cheers
I'll share my experience on building my room in case it is of some help to the OP, as your planned room is similar in size to what I have today and is a smaller room inside a larger one.

If you haven't already, I'd highly recommend Rod Gervais' Home Studio Recording - Build It Like the Pros book. I bought the Kindle version and studied it off and on for over a year (along with other materials, this forum and the home theater forum elsewhere) before building my room, which is very similar to what you're up against. There's some great detail in there about leafs (leaves?) and all the variations.

After a lot of reading and planning I went a slightly different route than you're suggesting and had outstanding results. The larger room shares the same footprint as the two-car garage below. I took the approach of stuffing the walls of the "studio" completely, covering them in burlap and then through trial and error brought the space back to life using wooden slats of various sizes. I also built an additional wall about 1.5" out from the studio wall that divides the larger space. So, two opposing doors to get in and out. The gap between the studio and larger room's walls is filled with pink fluffy.

So, no sheetrock other than what I had to do to match the existing soffit that outlines the perimeter of the larger room's ceiling. (Goes from 8' up, 3' in to 9' up.) I built various treatments for the ceiling, a cloud using 703, and big bass traps in the back bookending diffusors and slats. That 3' cavity I left behind the back wall is lined and sort of stuffed as well which helps a ton with lowend control. One key was being over the garage and not having to deal with living spaces below. Also, it was part of an addition we did to our house, so I was able to plan in detail as I took the addition from dried-in state all the way to the finish (sheetrock, texture, bathrooms, fixtures, etc. We hired paint). Main thing is that I wanted a structure I could remove with minimal effort if at a future point we decided to move.

Hope that's helpful.

Last edited by batlanyard; 4 weeks ago at 06:23 PM.. Reason: specified the OP
Old 4 weeks ago
  #27
Here for the gear
 

Quote:
Originally Posted by Soundman2020 View Post

Experiment by all means, but it really isn't necessary: as you know from your own studies of psycho-acoustics, the mechanisms of our ears and brain are quite well understood, so there's not really much need to "re-invent the wheel". The principles of what a studio needs in order to be usable are fairly well laid out already, in documents such as ITU BS.1116-3 and EBU Tech.3276, among others. They cover the practical specifications of what the speaker response, speaker layout, and acoustic response needs to be in a critical listening room. If you want the theory behind that, I'd suggest Floyd Toole's "Sound Reproduction" and also Kleiner and Tichy's "Acoustics of Small Rooms". Although I suspect you might have already read those!
I disagree with the bolded line to a significant degree. In my graduate work, we speculated on some phenomenae of unexplained or unverified nature. For example, we do not have a verified answer to why humans perceive the fundamental of a harmonic sound, rather than the entire sound image (fundamental + harmonics) like birds do [see Albert Bregman's related research]. I am not sure how one could say "the mechanisms of our ears and brain are quite well understood" when such fundamental and significant knowledge is still missing. Although I am not an advocator of headphones for mixing, I have doubts in some items you wrote regarding this- but, I won't open that can of worms since there's a lot of subjective "theories" even in the literature as to how the brain projects a sound image despite how it receives the signals.

I did read both those documents and unfortunately, according to their specifications my room does not qualify (but the information is useful). I have yet to find where that formula I quoted in an earlier post under this thread comes from.

Tichy's "Acoustics of Small Rooms" sounds promising. I will look into this.
Old 4 weeks ago
  #28
Here for the gear
 

Quote:
Originally Posted by avare View Post
What is your point?
Hi Andre,

More than establishing a point, I am trying to figure out if such a small room (36 m3) can be treated into a professional control room. I still did not find an example of a room this size, but I'll look into your two sources.

Thanks!
Old 4 weeks ago
  #29
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by mtsyas View Post
Hi Andre,

More than establishing a point, I am trying to figure out if such a small room (36 m3) can be treated into a professional control room. I still did not find an example of a room this size, but I'll look into your two sources.

Thanks!
You imply academic training and then use, being polite, phrases such as "professional control room". It can be done with over 12" absorptiom on all walls, compound membrane absorbers and or twisted Helmholtz absorbers.

Insulting professional studio designers with common misbeliefs will not help you.
Old 4 weeks ago
  #30
Here for the gear
 

Quote:
Originally Posted by avare View Post
You imply academic training and then use, being polite, phrases such as "professional control room". It can be done with over 12" absorptiom on all walls, compound membrane absorbers and or twisted Helmholtz absorbers.

Insulting professional studio designers with common misbeliefs will not help you.
I do not see how anything I wrote here is an insult. At least they were not intended so.
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
skeeballcore / So Much Gear, So Little Time
0
mario.junicic / Studio Building / Acoustics
11

Forum Jump
Forum Jump