Personal Studio project - Athens

What ? The studio to be constructed will initially serve as a project studio for personal use. It will have a descent Control Room and a rather small Play Room. Most of the recording I do as a guitarist is at this time silent, meaning that my set up is based in cabinet simulators or relevant software with the feed coming from attenuators in line level. However I want to be able to both practice and record acoustic drums in the booth as well as crank my amps. Key factor is that I normally do things alone, so remote desktop applications are essential infrastructure. In the future, producing might be the case. Phase 1 will be just the CR due to budget. PR soon to follow, God willing, austerity measures allowing, wife sparing me, son keep backing me up, daughter staying neutral. Where ? The owned property is in the basement of a six storey residential building, some 40 years old, with very poor insulation. Surrounding bearing elements (floor, walls, ceiling slab) are concrete. There is a adjacent basement to the back of the CR as well as a shaft servicing the WC windows on all floors. The area that will accommodate the studio is 40 m2 max and is limited as shown in the attachment. At the back, there are two quite big openings covered by single sheet clear glass on steel frames, giving no insulation and prone to rattling. Sound escaping to the back will create major issues since all bedrooms are facing the back and there is a very high retaining concrete wall (about 10 m) in appr. 6 m distance. Clearance prior to any works is 3,03 m. Proposed structure. Single leaf floating walls around the perimeter (see detail), floating floor (see detail), suspended ceiling (see detail). Questions Since the attenuation required is very extensive I plan to use 2 or 3 layers of 12.5 mm Gypsum Board and 3 layers of MDF (16/14/16 mm). As I think of it : 16 MDF/12,5 GB/14 MDF/Green Glue or PU flexible bonding/ 16 MDF/12,5 GB. Is there any particular sequence of the materials that is advantageous ? Do I have to make the ceiling the same? There is no static problem with the distributed load being around 50 kgr/m2. In the CR I try to kill flutter by these tilted panels which will be made of 18 mm MDF, and extensive application of diffusers both at the rear end as well as the ceiling. The rest of the ceiling area will be covered with absorptive panels. What do you think? Will the tilted panels work? I consider making the front 2 rows absorptive to avoid first reflections. Would splaying the front walls make substancial didderence? (I want to maintain the center as is for mounting a 42 in. monitor someday.) Thanking you in advance

Hi QAD, and welcome! :)

The studio to be constructed will initially serve as a project studio for personal use. ... It will have a descent Control Room and a rather small Play Room.

I see the control room on your drawings, but I don't see the "play room" (normally called the "live room" or "tracking room" in English). If you want to play live drums in there, then the details of how you are going to isolate that space are very important.

basement of residential building ... Surrounding bearing elements (floor, walls, ceiling slab) are concrete.

That's good! Basement means that your floor is mostly likely resting directly on the ground, which is excellent, and having concrete all around you means that you should be able to get good isolation.

as well as a shaft servicing the WC windows on all floors.

That might be a problem. That's a direct flanking path for sound throughout the entire building. It will be very important to seal up that service shaft very well.

At the back, there are two quite big openings covered by single sheet clear glass on steel frames, giving no insulation and prone to rattling. Sound escaping to the back will create major issues since all bedrooms are facing the back

Probably the bets way of dealing with that is to either replace those windows with bricke, if you can, or if not then seal the glass well so it cannot rattle and build a another wall a short distance from the glass, to close of that section completely.

Single leaf floating walls around the perimeter

Floating walls is not easy to do, and the method you are showing there is not going to work, unless you calculate the mass and deflection very carefully, and also figure out how to isolate and decouple the anchor bolts that hold that wall in place. You are also proposing a rather curious "sandwich" of materials for that wall! 16 mm MDF 12.5 mm drywall 14 mm MDF (green glue) 16 mm MDF 12.5 mm drywall All over a 125mm air gap. That is going to be over 7cm thick, and will weigh about 55 kg/m2. Why do you want that strange arrangement? You would be much better off with this: 16mm MDF 16mm Drywall GG 16mm Drywall That would be only 5cm thick, and would weigh about 30 kg/m2. Put that over a 150mm air gap, the wall would be the same total thickness and would isolate just as well. There is no need to use materials of different thickness (that is a myth), and using thin materials is not good (such as 12.5mm drywall). It is far better to use a few thick, dense layers than many thin, light layers.

floating floor (see detail)

Floating a floor es even harder to do right, and what you show there certainly will not work for that! Plus, you most likely do not even need a floating floor. These might help to understand: viewtopic.php?f=2&t=8173 viewtopic.php?f=2&t=8134 viewtopic.php?t=8135)

Since the attenuation required is very extensive

Yes, but you don't say how much. How many decibels of transmission loss do you need? Without knowing that, it is impossible to say whether what you are proposing will work or not, but I do guarantee you that the floating floor you propose will NOT provide high levels of isolation.

Is there any particular sequence of the materials that is advantageous ?

No. The sequence makes very little difference at all, if any. Sound waves react to mass, rigidity, damping and decoupling. As long as you have a good amount of rigid mass on each leaf, a large enough air gap between them, and plenty of damping in the cavity, then the sequence of materials makes very little difference.

Do I have to make the ceiling the same?

Yes. All sides of the room have to be isolated to the same level. If not, sound will just take the easy path out through the weakest side.

There is no static problem with the distributed load being around 50 kgr/m2.

With the sandwich of materials that you propose, you would be exceeding that. The wight would be well over 50 kg/m2, just from the MDF and drywall, without considering the weight of the joists, insulation, HVAC, electrical, and the acoustic treatment that you will need to hang inside.

In the CR I try to kill flutter by these tilted panels which will be made of 18 mm MDF,

They would need to be angled at least 12° in total (6° on each side), to do that, and the angles in your diagram don't seem to be big enough. Also, if those are just plain wood panels over frames, then they will also act as tuned membrane absorber ("panel traps"), that might or might not be tuned to useful frequencies. What frequencies are you projecting for your modal issues? Flutter echo can also be dealt with by using absorption on the walls, or by angled slot walls.

extensive application of diffusers both at the rear end as well as the ceiling

If you are talking about numeric-based diffusers, such as binary sequence, skylines, or QRDs, then that would be a big mistake: the room is not big enough to be able to use those types of diffuser. Diffusers are only appropriate in large rooms.

What do you think? Will the tilted panels work?

Yes, they will work, but it does not look like you will have enough absorption in that room to attain the EBU recommendations. You might want to replace some of those panels with simple absorption.

consider making the front 2 rows absorptive to avoid first reflections.

That would be a good idea, yes.

Would splaying the front walls make substancial didderence? (I want to maintain the center as is for mounting a 42 in. monitor someday.)

That depends on your design concept: If you were planning an RFZ design, then splaying the walls is the best way to do that. But you do not seem to be planning that, so you are fine without splaying. - Stuart -

Thanks a lot Stuart Just adding some 3d. Will comment later on.

I see the control room on your drawings, but I don't see the "play room" (normally called the "live room" or "tracking room" in English). If you want to play live drums in there, then the details of how you are going to isolate that space are very important.

I’ve posted the general intended layout, which answers the position and appr dims of the tracking (thanks) room.

That's good! Basement means that your floor is mostly likely resting directly on the ground, which is excellent, and having concrete all around you means that you should be able to get good isolation.

A known issue with the concrete slabs, as per the structural details followed here, is that there is no slit joint between the slab and the concrete walls. Quite contrary, the rebar and free casting are firmly joining these elements. So even if the soil provides for intense dampening, the sound can easily travel.

Floating walls is not easy to do, and the method you are showing there is not going to work, unless you calculate the mass and deflection very carefully, and also figure out how to isolate and decouple the anchor bolts that hold that wall in place.

Can you pls explain why the floating of the walls will not work? The whole structure will rest on a 25 mm thick sylomer stripe, 7-8 cm wide, which will yield appr 3 mm on full load. The columns will be fixed at the ceiling with rubber decouplers. The lower wooden section will not be bolted or otherwisw fixed to the existing floor. It will be secured from lateral movement with sylomer pads against fixed angles.

You are also proposing a rather curious "sandwich" of materials for that wall!

As for the strange sandwich, which is probably an overkill, the reason is that since I’ll have to hang or fix many panels etc (some of them heavy too) a 36 mm GB with a underlying MDF would not be convenient at all. Plus mass will keep the neighbors cool. I know it’s too much, however I can’t take any risk on that. I’d rather pay a little more than having trouble. I’ll switch to 18 mm GB though, thanks.

Floating a floor es even harder to do right, and what you show there certainly will not work for that! Plus, you most likely do not even need a floating floor.

Yes, but you don't say how much. How many decibels of transmission loss do you need? Without knowing that, it is impossible to say whether what you are proposing will work or not, but I do guarantee you that the floating floor you propose will NOT provide high levels of isolation.

For the floor structure, also sylomer stripes (different grade, giving about 2mm yield) on fixed and leveled beams. Does it seem OK? For the layers of MDF, would you go for screwing them or just gluing with a polyurethane compound (it remains flexible but stronger than GG) for dumping? Maybe both? About the required attenuation, regretfully I can not quantify (hence the overkill...) but it should take a loud drumset and tame it to "listening to the radio" level for the tracking room, which I haven't yet really thought, since it will be constructed at a later stage.

They would need to be angled at least 12° in total (6° on each side), to do that, and the angles in your diagram don't seem to be big enough. Also, if those are just plain wood panels over frames, then they will also act as tuned membrane absorber ("panel traps"), that might or might not be tuned to useful frequencies. What frequencies are you projecting for your modal issues?

The wall panels are angled 6° each side already. Since there is an issue of these behaving like tuned resonators, I think that I might tune them in a later stage (after measuring the room). For the modal distribution, I'll repost.

If you are talking about numeric-based diffusers, such as binary sequence, skylines, or QRDs, then that would be a big mistake: the room is not big enough to be able to use those types of diffuser. Diffusers are only appropriate in large rooms.

Please explain or give link as to why numeric based diffusers will not work. What would? BBC say? Is primitive root considered also numeric?

That depends on your design concept: If you were planning an RFZ design, then splaying the walls is the best way to do that. But you do not seem to be planning that, so you are fine without splaying.

Can you please explain or give link for what’s the difference between RFZ and LEDE? Is just the area of the monitor enough to deviate from or cancel out a RFZ? You're most helpfull indeed. Thanks again. QAD

I’ve posted the general intended layout, which answers the position and appr dims of the tracking (thanks) room.

But I still don't see the isolation plan for that room. Just the rough outline. Drums are the hardest of all instruments to isolate, due the very high sound pressure levels, and the amount of energy in the low frequencies. So it is important to see what the plan is for the tracking room, to check if it will work or not.

A known issue with the concrete slabs, as per the structural details followed here, is that there is no slit joint between the slab and the concrete walls. Quite contrary, the rebar and free casting are firmly joining these elements. So even if the soil provides for intense dampening, the sound can easily travel.

You are talking about impact noise, but there will not be any impact noise in the control room! Impact noise is what you find in tracking rooms, but seldom in control rooms. Control rooms might have problems with airborne sound, but not with structure-borne sound. So I still don't see the need for trying to float your control room floor.

Can you pls explain why the floating of the walls will not work? The whole structure will rest on a 25 mm thick sylomer stripe, 7-8 cm wide, which will yield appr 3 mm on full load.

Which type of Sylomer, and what is the projected loading? But once again, you are talking about impact noise. You can indeed float a lightweight deck like that, and it will deaden impact noise, but you are forgetting that there will still be an air gap under your floor, and the deck itself can vibrate. So you have a light-wight vibrating membrane over a resonant air cavity. That is also known as a "drum"... :) Two layers of 20mm MDF over a 50mm air gap on top of a concrete floor slab has a fundamental resonant frequency of about 45 Hz. That's an F on a bass guitar. So each time a bass guitar happens to hit an F, the floor will vibrate. And since there is insulation down there, the Q is broader, so it will most likely vibrate at E, F, G, and even A of the next octave.

The lower wooden section will not be bolted or otherwisw fixed to the existing floor. It will be secured from lateral movement with sylomer pads against fixed angles

It might be easier and cheaper to use bolts with isolation collars around them.

As for the strange sandwich, which is probably an overkill, the reason is that since I’ll have to hang or fix many panels etc (some of them heavy too) a 36 mm GB with a underlying MDF would not be convenient at all. Plus mass will keep the neighbors cool. I know it’s too much, however I can’t take any risk on that. I’d rather pay a little more than having trouble.

I think you are not understanding the acoustic isolation issues of using many thin panels instead of a few thick panels. All o the panels together provide the overall mass, yes, but the individual panels still have their own characteristics, and still act individually: Thin panels (12.5mm) are much more flexible than thick panels, and have undesirable resonant characteristics. If you really do need that much mass on the walls, then use 25mm MDF as the first layer, then two layers of 16mm drywall with GG in between. That will give you about 45.5 kg/m2 surface mass. More than enough. PUt that over a 20cm air gap, and you get very, very good isolation. I'm also not sure why you think that 36mm of drywall (it would only be 32mm, not 36) over the MDF would not be convenient: You cannot attach your panels to the MDF layers that are not in direct contact with the studs, as that would put sheer stresses on the intervening layers of drywall, and on the screws. Drywall does not stand up well to stress loads. Whatever you attach on top of the wall MUST be screwed right through to the base layer of MDF. You will need long screws, sure, but that's the safe and correct way to do it, regardless of whether it is "convenient" or not. You also say that you will be attaching "very heavy" panels to the walls, but I don't see why they would be heavy. Acoustic absorption panels are not that heavy. Even a full 4' x 8' panel made of mineral wool only weighs about 15 kg or so.

About the required attenuation, regretfully I can not quantify (hence the overkill...) but it should take a loud drumset and tame it to "listening to the radio" level for the tracking room,

You really should quantify it before you start building anything! It isn't sensible to build something without know why you are building it, for what purpose, or how it works. You should get a sound level meter and actually test: measure how loud your drums are, measure what you consider to be a reasonable level (the "listening to the radio" level), and subtract the two numbers. The result is how much isolation you need. Roughly, drums put out around 110 - 115 dB. "listening to the radio" is maybe 65 dB. So you need roughly 50 dB of isolation. The plan I'm giving you above (25mm MDF plus 2 x 16mm drywall over a 20cm air gap) will give you roughly 57 dB of isolation, and the MSM resonance would be about 14 Hz, so the wall will isolated from 21 Hz upwards, and isolates well above 28 Hz. That's really, really good isolation.

the tracking room, which I haven't yet really thought, since it will be constructed at a later stage.

Then you have a major problem! The wall of the tracking room is part of your MSM isolation system! Unless you build that, your entire isolation system will not work. Two-leaf decoupled MSM construction requries BOTH leaves in order to work. One leaf is the side wall of your control room, and the other leaf is the side wall of your live room. Unless you have both, then you don't have isolation.

Since there is an issue of these behaving like tuned resonators, I think that I might tune them in a later stage (after measuring the room)

If you build them correctly, as proper slot walls, then yes, you can tune them. But if you were hoping to tune them as panel traps in order to deal with modal issues, then that is very unlikely to work. Modes are very specific frequencies, and panel traps are hard to tune. Theory is one thing, but real-lie is another. Trying to tune panel traps to hit a specific mode is really hard to do. Your chances of success are slim. Build broad-band slot walls instead.

Please explain or give link as to why numeric based diffusers will not work.

Pretty much anything written by D'Antonio and/or Cox on numeric sequence diffusers should help you understand that. This is probably a good one: http://www.amazon.com/Acoustic-Absorber ... b_title_bk According to D'Antonio, you need a distance of at least three times the longest wavelength between the diffuser and your ears. Cox says a minimum of 3m, regardless of wavelength, and I've seen other suggestion that it should be 7 times the longest wavelength. So for most home studios, it simply is not practical to use diffusers. Or if you do use the, then tune them to very high frequencies, such that the longest wavelength is short enough to fit in three times between the diffuser and your head. But if you tune then that high, then what's the purpose of the diffuser anyway?

Can you please explain or give link for what’s the difference between RFZ and LEDE?

LEDE was a design initially used in the 70's, with the basic concept being to try to kill the entire front end with large amounts of absorption, to stop all reflections from getting to the ears of the engineer, then making th rear half of the room reflective but diffuser, so the room didn't sound so terrible, like an anechoic chamber. That concept proved to be uncomfortable to work in as it was unnatural, just didn't "sound right". RFZ is an extension of the same basic idea, but without "killing" the front end with absorption. Instead, the front/side walls are angled just right such that the first reflections are directed away from the ears of the engineer, towards the back of the room, and the rear of the room becomes either absorptive or diffusive, or both, depending on the size of the room and the rest of the design. So with RFZ, the front of the room can be kept much more live, with reflective surfaces and less absorption than LEDE, and the rear of the room can be much less live, with the deep absorption that is needed to control the bass.

Is just the area of the monitor enough to deviate from or cancel out a RFZ?

No. The monitors themselves are irrelevant to the basic principle of RFZ design (Of course, they are extremely relevant to the overall room design!). What mater is the way the front part of the room is angled. The angles must be just right to keep ALL first reflections away from the mix position. Overall, RFZ and LEDE have the same goal at heart, and in fact RFZ is often confused for LEDE by people who don't realize the difference, but true LEDE is no longer considered a good design for studios. Many of the more modern "LEDE" rooms are actually not LEDE at all! In reality, they are RFZ, but with the wrong name on them! :) - Stuart -