Hi all,
Fantastic forum here, a wealth of knowledge.
I'm currently researching build options for a mixing/production studio in my backyard, and would love some input.
- Available ground area is 3.8 x 8 meters.
- This is for production and mixing only (and some quiet overdubs), I do my "loud" recording elsewhere.
- Sound isolation is not an issue, I'm primarily concerned with good, even sound reproduction.
- I plan on building on a concrete block (not poured yet), but apart from that.. I'm researching :)
- Budget is not large, around 10k.
My initial question is regarding wall construction materials, specifically timber vs besser block. What would be the best route to take?
Keeping in mind (if it matters) that I do plan to have a window to the outside, I like natural light.
Thanks again for any ideas.
Cheers,
Skye
New studio build, preplanning research
Originally posted at johnlsayers.com, topic 17739.
Hi Skye, and Welcome! :)
So this is going to be a single-room studio? Meaning a control room that will do double-duty for tracking?
Are you sure? :) So it never rains where you live? No thunder, no lightning, no wind, no hail? No aircraft / helicopters flying over? No cars arriving/leaving/passing by? No neighbors, dogs, lawnmowers, telephones, radios, people talking? No other sound sources around you at all? Those are all things that are often overlooked, but that can totally ruin your best take of a "quiet overdub".- Sound isolation is not an issue,
If you are not at all concerned about isolation, then it doesn't really matter: either will do, since all you need it for is to provide the general shape of the room, and enough structural integrity to keep it all together. So cost and ease of construction would then be the major issue: which one would work out less expensive and/or easier to build, where you live? If it turns out that the concrete blocks are cheaper, then go with that.My initial question is regarding wall construction materials, specifically timber vs besser block. What would be the best route to take?
The window doesn't really affect things much: it would be pretty much the same to put a window in a concrete block wallas it would in a timber-framed wall. Do you have any rough sketches of what you have in mind yet? If so, then maybe you could post those? - Stuart -Keeping in mind (if it matters) that I do plan to have a window to the outside, I like natural light.
Hi Stuart, thanks for the welcome :)
I've answered your questions inline, to the best of my abilities.
First off, I live in Ballarat (regional Victoria, Australia).
Correct. In fact it will be used soley for mixing 95% of the time. Much of the music I create is electronic/synthetic-based (various forms of electronica and "avant-garde"/ambient/soundscape) and is recorded directly through the console.Hi Skye, and Welcome! :) So this is going to be a single-room studio? Meaning a control room that will do double-duty for tracking?
Heh, I can see where you're going.. The space that I have available is at the back of our fairly deep block (and also the back of all the adjoining blocks) so is not in close proximity to other humans. Any non-DI'd tracking that I will be doing will be an occasional electric guitar overdub. There is actually very little ambient noise around - we are set fairly far back from the one nearby road, and behind us stretches back to semi-bushland. Sure, there's always the possiblity of the neighbour mowing the lawn or something, but to be honest this is a personal studio only, so I'm not too fussed about waiting half an hour for her to finish, I've been making music in make-do conditions for so many years that I'm accustomed to working with the environment :)Are you sure? :) So it never rains where you live? No thunder, no lightning, no wind, no hail? No aircraft / helicopters flying over? No cars arriving/leaving/passing by? No neighbors, dogs, lawnmowers, telephones, radios, people talking? No other sound sources around you at all? Those are all things that are often overlooked, but that can totally ruin your best take of a "quiet overdub".- Sound isolation is not an issue,
Interesting.. I have actually purchased Rod Gervais' book (and am 3/4 through it), but I'm still a little confused when it comes to isolation vs acoustics/treeatment - most discussions (understandably) tend to address both simultaneously, so I've had a hard time separating the two. In particular, trying to work out (from an acoustics point of view) the pros and cons of timber stud vs masonary construction (surely the rigidity of masonary would "reflect" sound quite differently than timber / plasterboard?) .If you are not at all concerned about isolation, then it doesn't really matter: either will do, since all you need it for is to provide the general shape of the room, and enough structural integrity to keep it all together. So cost and ease of construction would then be the major issue: which one would work out less expensive and/or easier to build, where you live? If it turns out that the concrete blocks are cheaper, then go with that.My initial question is regarding wall construction materials, specifically timber vs besser block. What would be the best route to take?
[/quote] At the moment I have merely a "floorplan" of the available space (literally a rectangle in the maximum available dimensions mentioned, 3.8 x 8m) in Sketchup. My next task is to divide that into a good ratio (if necessary) and get to work sketching up my ideas for the internal layout (with the help of this forum and Mr Gervais' awesome book). As soon as my plan becomes more than a flat rectangle I will post it as I'd love to hear any and all feedback / ideas. Thanks again :) Cheers, SkyeDo you have any rough sketches of what you have in mind yet? If so, then maybe you could post those?
Yeah, that got me for quite a while too! So let me see if I can maybe confuse you even more... Isolation just means "stopping sound from getting from "A" to "B". You can't actually stop sound completely, of course: no conceivable barrier can prevent a sufficiently loud sound from getting through, so true "soundproofing" is impossible. But you sure can make it really hard for the sound to get there, and decrease the level substantially! I'm sure you already know that sound is just "vibrations in the air", or pressure variations, to be more technically correct. And when those vibrations hit any material object, they transfer energy to it, and make it vibrate at the same rate. Which in turn means that the OTHER side of the object also vibrates, transferring the energy back into the air again, and hence the object has not stopped the sound from getting through. It turns out that there really aren't many ways of actually stopping sound, according to physics. The first thing you can do is to make that barrier so rigid and stiff that the sound waves cannot make it vibrate in the first place. Unfortunately, there are no such materials available on planet earth: Even solid bedrock isn't rigid enough to do that. That's why earthquakes can be felt hundreds of km away: the rock transmits the vibrations. The second thing you can do, is to make the barrier so massive (heavy) that the sound waves cannot make it vibrate. Once again, there are no such materials. Once again, earthquakes are the perfect example: even the entire planet isn't massive enough to stop them! The third thing you can do is to "decouple": take away all possible paths for the vibration to follow between "A" and "B". That also includes taking away the air, since sound travels pretty well through air. So if you can persuade NASA to let you build your studio on the moon, you'll be fine! :) Otherwise, no luck. There's a final option: "damping". You can sort of make the sound wave move through molasses, bog it down, so it "runs out of steam". You do that by putting fibrous things in its way, such fluffy insulation. But you need an awful lot of "molasses" to fully damp a sound wave down to nothing! Huge amounts. Out of the question, for any realistic studio. And that's about it. There are no more options: Mass, stiffness, decoupling, damping. There are no other ways to stop sound. And none of these four are very good.... by themselves... ! But it turns out there's another option: by combining all of the above in certain ways, you can really have a huge effect. for example, if you set up two "leaves" of massive, rigid surfaces, such that they are not connected to each other (decoupled), then put some damping between them, you have an excellent barrier that really does a great job at stopping sound from getting out of your room. Such as, for example, two sheets of drywall on separate stud frames, with only an air gap between them, and insulation in the air gap. Bingo! It works because it is a tuned filter, sort of like a parametric equalizer on your console or DAW: it is a bandpass filter, tuned to one frequency, which it allows to pass really well, but it actively resists all other frequencies. So tune if you tune it right, such that the "band" that it "passes" is subsonic, then it does a darn good job of isolating all sonic sounds. That's a "fully decoupled two-leaf MAM" wall, in technical jargon, and it isolates very well. Done right, it can stop isolate to levels of 50, 60, even 70 dB: It stops a lot of sound from getting out. OK, here's the hitch: if the walls stop sound from getting out of your room, then obviously the sound stays in the room! It can't go anywhere else, so it must still be inside the room. The walls cannot destroy the sound: they just bounce it back, so it stays in the room, bouncing around all over the place, making the room sound bad. That is called "reverberation". It is what you hear in an empty room, with nothing but the walls, floor and ceiling around you: Ugly. The room sounds bad because the sound stays in, reverberating around between the walls. The better the walls are at isolating, then worse the room sounds inside. If you think about it, the exact opposite of a room is open air: if you set up your DAW in the middle of an empty field, with no trees, buildings, or anything else around, then it sounds great, because no sound ever comes back to you: you hear the speakers, pure and clear, with no room to affect the, at all. They sound just the way the manufacturer intended, and you'll have the best possible sound from those speakers, coming directly at your ears, not muddied by any reflections, reverberation, or any other artifacts caused by the room. OK, so those are the two extremes: a "room" that does not isolate at all, allows all of the sound to escape, none of it comes back, and sounds great. A room that is highly isolated reflects back ALL of the sound, and sounds terrible. That's where treatment comes in: since a well isolated room sounds terrible, the purpose of treatment is to make it sound good again. The idea is to control the reverberation, reflections, etc. so that the room itself does not add anything to the sound, nor subtract anything from the sound. It should be neutral, flat, "not there". It should not "color" the sound. And just like for isolation, it turns out that there are only a limited number of options available for accomplishing that. You can absorb some of the sound, you can diffuse the sound, you can reflect it, you can diffract it, you can force it to cancel itself out, and that's about it. So basically your options are absorbers, diffusers, reflectors, diffractors, and resonators. There's not much else you can do. Diffraction isn't much use, and is really hard to do. Resonators are a pain to get right. Diffusers are not suitable for small rooms, for reasons too complex to go into here. Reflection is part of the problem. That leaves, basically, absorption. That's why you see that so much of the treatment in small rooms is based around very large amounts of fluffy insulation, since it is really good at absorbing sound at low cost. Yes, you do also see some forms of resonator, and most studios also use angled reflection to send the sound waves away from places where you don't want them, and towards absorption, but the main active ingredient in treatment is plain old simple absorption. That's the "make it move through molasses" concept. As sound waves move through the fibers of insulation, they make the fibers move just a little, and that robs the sound wave of just a bit of acoustic energy. The fibers turn the acoustic energy into low-grade heat, so it is no longer sound. Each fiber only takes out an infinitesimal amount of energy, but if you have enough fibers of the right type ("billions and billions"), you can make a big dent. So absorbers are usually large, and they are usually deep. They have to be, to have enough effect. So, by putting the right type, thickness and size of absorbers in the right place, aided by reflectors, diffusers and resonators, you can get the sound under control again, and make the room sound less bad. So that's basically it: Isolation stops sound leaving, keeping it inside, making the room sound bad. Treatment makes it sound good again. Of course, it's not quite that simple, but that's the basic concept. Yes, isolation can also be part of treatment, and yes treatment can affect isolation, but it helps to think of the two as independent, separate and even opposite things. Isolation is done with hard, solid, massive, rigid things, treatment is done with soft, flexible, fluffy, light things. (Once again, not really exact, but a good concept). Not sure if that helps, or just totally confuses the hell out of you! :)but I'm still a little confused when it comes to isolation vs acoustics/treeatment - most discussions (understandably) tend to address both simultaneously, so I've had a hard time separating the two.
Actually, there's not a huge difference, of you build the timber / plasterboard wall to the same level of isolation as the masonry: If they are both "stopping the escape" of the same amount of sound, then they are bot reflecting roughly the same amount / spectrum of sound back into the room. You tend to think, "intuitively" that the brick must reflect more, and be more "echoey" but in reality for the same level of isolation, there isn't as much difference as you might expect. Ever moved into a new house, and heard how "hollow" and "reverberant" all of the rooms sound, even though the walls are just plasterboard? Imagine how much worse it would be if those walls were actually reflecting back even MORE sound...In particular, trying to work out (from an acoustics point of view) the pros and cons of timber stud vs masonary construction (surely the rigidity of masonary would "reflect" sound quite differently than timber / plasterboard?)
For a control room, it's always a good idea to start with a decent ratio based on a rectangle. You can modify the shape as needed, if you want (depending on the design criteria you choose to follow), but starting with a rectangular shape with a decent ratio is a good place to start. Looking forward to seeing your plans! - Stuart -My next task is to divide that into a good ratio (if necessary) and get to work sketching up my ideas for the internal layout (with the help of this forum and Mr Gervais' awesome book).
Thanks for the detailed reply, much appreciated.
Hmm.. So, with this in mind, as well as my fairly low concern for isolation due to my immediate environment and non-tracking requirements, would it not be too silly to say that, given a decent l/w/h ratio, I should not be overly concerned with the mass/density of the walls, as I actually *want* as much sound as possible to pass through unhindered? (and yes, I realise the same goes for sound coming in, too!). I ask because for a short while I had a small mixing setup in a kind of closed-in sunroom at a friend's place (uninsulated weatherboard, louvre windows that didn't close all the way, it was freezing in there!), and the sound was very.. washy, like all the guts had dropped out. I assumed this was because not *enough* sound was trapped inside, but what do I know? :D Anyway I'm hard at work looking at ratios at the moment (more confusion!). The problem I'm seeing is, due to the limited width available (3.8m max), the "recommended" ratios limit the maximum length to considerably shorter than my available space (3.8 x 8.0). And since I have the extra space, I'd prefer to use it (for a couch/reading area & electronic drumset). One further question I have regarding materials, I'm now not sure if a poured slab is feasible in this location (soft ground, apparently) so I'm curious if a plywood floor on concrete footings would have any acoustic repercussions? Thanks again for your insight, already a lot of food for thought. Cheers, SkyeOK, here's the hitch: if the walls stop sound from getting out of your room, then obviously the sound stays in the room! It can't go anywhere else, so it must still be inside the room. The walls cannot destroy the sound: they just bounce it back, so it stays in the room, bouncing around all over the place, making the room sound bad. That is called "reverberation". It is what you hear in an empty room, with nothing but the walls, floor and ceiling around you: Ugly. The room sounds bad because the sound stays in, reverberating around between the walls. The better the walls are at isolating, then worse the room sounds inside. If you think about it, the exact opposite of a room is open air: if you set up your DAW in the middle of an empty field, with no trees, buildings, or anything else around, then it sounds great, because no sound ever comes back to you: you hear the speakers, pure and clear, with no room to affect the, at all. They sound just the way the manufacturer intended, and you'll have the best possible sound from those speakers, coming directly at your ears, not muddied by any reflections, reverberation, or any other artifacts caused by the room.
Well, you are forgetting one issue here: Murphy! His "law" always gets you... I mentioned that things aren't as simple as I painted them above, and one of the complications that I conveniently neglected to mention, is that everything depends on frequency: Walls do not isolate the same amount for every frequency, across the entire spectrum. It varies. Even with simple "mass law" (the equations that govern a single-leaf wall made of just one layer of mass), it turns out that isolation is about 6 dB higher in each octave than for the next lowest octave. In other words, isolation improves by 6 db per octave. So such a wall isolates a 500 Hz tone 6 dB better than it does a 250 Hz tone, and a 1 kHz tone yet another 6 dB better. With a tuned MSM wall, the slope is 18 dB per octave. But! That's not all: Murphy again... the rise is not constant. There are regions where isolation drops again as frequency increases, such as at the MSM resonant frequency, and at the coincidence dip: And the 18 dB/octave rule is also not constant: below MSM resonance it drops back to 6 dB/octave, and somewhere above the coincidence dip it rolls off to something more like 12 dB/octave. So, that's my long, meandering background for getting to the point: Even in a room with lousy isolation, it still isolates some frequencies really well, others not so much, and others very poorly. In general, isolation at lower frequencies is always worse, and isolation at higher frequencies is always better. So going back to my simplified concept: with a lousy isolation wall, the lower end of the spectrum simply disappears out through the wall, and is gone. Mids stick around halfheartedly, except at the coincidence dip, where they join their low frequency buddies and rush through the exit, but to a much lesser extent. And highs don't go anywhere: they stay in the room. So a badly isolated room can sound "like all the guts had dropped out", for example... :) And that isn't pleasant to mix in: your mixes will not translate well, since you are not hearing a clear, accurate depiction of how your music actually sounds: rather, you are hearing the sound after it has been "colored" by the room.would it not be too silly to say that, given a decent l/w/h ratio, I should not be overly concerned with the mass/density of the walls, as I actually *want* as much sound as possible to pass through unhindered? (and yes, I realise the same goes for sound coming in, too!).
That's basically it, but selectively: some notes stayed in, others departed, and yet others sort of waffled around a bit, then died.I assumed this was because not *enough* sound was trapped inside,
Don't sweat ratios too much: some folks go overboard on ratios, when it really isn't necessary. As long as you are far away from the "bad" ratios, and reasonably close to one of the "good" ratios, you'll be fine. But if you want to make good use of that "extra" space, have you considered maybe turning it into storage or a mini-booth?Anyway I'm hard at work looking at ratios at the moment (more confusion!). The problem I'm seeing is, due to the limited width available (3.8m max), the ratios limit the maximum length to considerably shorter than my available space (3.8 x 8). And since I have the extra space, I'd prefer to use it (for a couch/reading area & electronic drumset).
Not a good idea, for several reasons. First and foremost, that's just a drum head! Plywood on a frame is exactly the same principle as a membrane stretched over a cavity. And they both resonate.... In order to make it stiff enough and massive enough to NOT resonate terribly, you'd need several layers of plywood screwed together, or better still, pour a layer of concrete over a single layer.... - Stuart -so I'm curious if a plywood floor on concrete footings would have any acoustic repercussions?
Thanks again for the detailed response, Stuart.
Ah, sort of how I was thinking, thanks for clearing that up. Yeah that space was certainly unpleasant to mix in. Fortunately it was only for a short while, and I did not need to do anything "critical" while I was there.Well, you are forgetting one issue here: Murphy! His "law" always gets you... I mentioned that things aren't as simple as I painted them above, and one of the complications that I conveniently neglected to mention, is that everything depends on frequency: Walls do not isolate the same amount for every frequency, across the entire spectrum. <snip> So going back to me simplified concept: with a lousy isolation wall, the lower end of the spectrum simply disappears out through the wall, and is gone. Mids stick around halfheartedly, except at the coincidence dip, where they join their low frequency buddies and rush through the exit, but to a much lesser extent. And highs don't go anywhere. So a badly isolated room can sound "like all the guts had dropped out", for example... :)would it not be too silly to say that, given a decent l/w/h ratio, I should not be overly concerned with the mass/density of the walls, as I actually *want* as much sound as possible to pass through unhindered? (and yes, I realise the same goes for sound coming in, too!).
I'm trying not to get hung up on them, just attempting to stay away from even multiples. I am considering a vaulted ceiling (ie peaked roof without a hung ceiling) so I'm sure that will throw all the ratio calculations out anyway.As long as you are far away from the "bad" ratios, and reasonably close to one of the "good" ratios, you'll be fine. But if you want to make good use of that "extra" space, have you considered maybe turning it into storage or a mini-booth?
Okay, cool, so slab it is :) So I've attached my first plan, it's all very rough at the moment, just trying to sketch out my requirements and how they fit into the space available. Regarding the "extra space", I really don't have a need for a booth or storage, but what I did neglect to mention is that I would like to have a second work area in there, at the other end, for the day job (web programmer, so a desk & a laptop is all it is). Those are windows on the left wall. Size, positioning is kinda random for now, just playing. Is a long, basically unbroken space like that a problem, acoustically? I keep seeing mention of keeping the rear wall "as far as possible from the listening position". I have also thought about building some dense, moveable partitions to break up the space between the studio and office. Again, the dimensions below are not set in stone, as it's just an empty bit of yard at the moment. They're the maximum available. Many thanks, SkyeNot a good idea, for several reasons. First and foremost, that's just a drum head! Plywood on a frame is exactly the same principle as a membrane stretched over a cavity. And they both resonate.... In order to make it stiff enough and massive enough to NOT resonate terribly, you'd need several layers of plywood screwed together, or better still, pour a layer of concrete over a single layer....so I'm curious if a plywood floor on concrete footings would have any acoustic repercussions?
Quick update regarding the one long room issue, I've noticed that if I did separate the space into two areas, having the control rool area at 4.6m in length (and a bit of extra tweakery) would get close to the 1:1.14:1.39 ratio (yes I'm trying not to get obsessed with the magic numbers, promise!).
I really do like the idea of one large open-plan space, but am totally open to compromise if this will cause acoustical issues :)
Skye
While having lots of space behind you is good, like many things in Acoustics, "more is not always better". If you take a look at the range of good ratios for control rooms, they start fading out beyond the point where room length is more than about 2.2 times room height, and also when the width gets to be much greater than about 1.6 times the height. Plus, the longer and thinner the room gets, the worse it gets. I'm not sure how high your room is, but I'm assuming about 3m: I can't seem to find any decent ratios at all in that region.
I would seriously consider splitting the room in two. If you like the idea of visibility, then set up the rooms so that the control room faces the 2other" room (live room?), and put a window in the front wall of the control room, between the speaker soffits. Or even make that into a glass door, for easy access between the two rooms: leave it open, except when you need to do critical listening.
One other thing: I'd really suggest that you consider soffit mounting your speakers, instead of having them on stands. You have plenty of space to do that properly.
- Stuart -
Thanks again,
I've been playing about with splitting the room and the ratios are a lot better. As mentioned previously, there is no "live" room - this space is for mixing & production/composition only. There rest of the space will form a lounge area / home office / "den". My concern was not for visibility between the spaces, per se, rather that I prefer an "open plan" feel rather than seperate spaces, but I'm willing to compromise this to optimise acoustic performance. Regarding soffit mounting, is this still applicable for nearfield monitors? I guess I hadn't considered soffit mounting due to the extra cost (remember, this is a from-scratch build; my upper limit is 10k, and that needs to cover everything from slab to acoustic treatment). I'm not particularly DIY-oriented, certainly not with carpentry, and anyway my time is quite full with work, music production and a young baby :) ..so I'll be contracting the work out. Also, I'm not planning on building a room within a room (budget), so would soffit mounting the speakers into the corners of this space would place them way too far apart? In which case, I guess width of the space would have to be considerable narrower than 3.75 meters? Again, your insight is very much appreciated :) SkyeI would seriously consider splitting the room in two. If you like the idea of visibility, then set up the rooms so that the control room faces the 2other" room (live room?), and put a window in the front wall of the control room, between the speaker soffits. Or even make that into a glass door, for easy access between the two rooms: leave it open, except when you need to do critical listening.
Hi Stuart,
any further thoughts pertaining to my last post?
Much appreciate,
Skye
Looks much better like that!
Yup! Some people are horrified by that idea, but the principles are the same, regardless of what name tag the manufacturer puts on the box. In fact, ask six different manufacturers what the definition of "nearfield" is, and you'll get six different answers, some of which will contradict each other! :) some will tell you that it is a certain distance: "close than x feet is near, further than that is far". Others will tell you that it is related to the dimensions of the speaker cabinet: "Listening from less than 1.23769 times the height of the speaker is near field, further is far". Others will come up with even more esoteric reasoning, based on their own proprietary design features. Others might even be honest enough to admit that they don't know, since there is no technical definition... If you don't believe me, do a Google search for the definition of nearfield monitor. :) In reality, "nearfield" refers more to the room than it does to the monitor. If you are seated closer than the critical distance, then by definition you are in the direct field, which some would call the near field. The "critical distance" is the point where the reverberant field in the room is at the same level as the direct field. Easy to find, well defined, logical. And totally unrelated to the speaker itself! It is a room issue, not a speaker issue. So the room should be designed to "push back" the critical distance as far as possible, so that you are always listening in the direct field, never in the reverberant field. OK, that's part of the issue. Another part really does have to do with the speakers. First, some background: All speakers radiate sound. that's what they do, their entire purpose in life. Good studio speakers should radiate sound equally at all frequencies. Ie, they should have "flat response". But there's a problem... High frequency sounds are radiated more like rays, in straight lines, or rather in a cone-shape, like a beam of light shining out. Low frequencies are radiated like a sphere, spreading out equally in all directions. Obviously, if the speaker is putting the same amount of power into the highs and lows, then the highs are going to sound 6 dB louder, since all the power is coming at you directly, while the lows are going to sound 6 dB quieter, since the power is spread around in all directions. Ooops! There's a major power imbalance here. So the manufacturer has to increase the power by 6 dB for the low end. But where? At what frequency? Should he increase power below 500 Hz? Below 1,567 Hz? Below 223 Hz? Hmmm.... It turns out that the frequency where bass energy starts "wrapping around" behind the speaker is directly related to the dimensions of the front panel of the speaker, called the "baffle". Bigger baffles mean that the problem does not occur until lower frequencies. Very big baffles means it doesn't happen until very low frequencies. An infinite baffle means it does not happen at all! Unfortunately, speakers with infinitely large front baffles are hard to fit in boxes, put on shelves, take home in your car, etc. Even "large with respect to the lowest frequency" is still no good, as the baffle would have to be dozens of feet wide to meet that criteria. So that's not an option. Bummer. So manufacturers have to resort to electronic trickery inside the box to send 6 dB more power to the woofer, but only below the "baffle step" frequency, not above it. So the circuitry inside the speaker must compensate for this issue. All small speakers suffer from the baffle step issue, as well as edge diffraction and other problems. Manufacturers can reduce it by careful design of the circuitry, and also the design of cabinets, with angled or rounded edges, to make the effect smoother, etc. But of course, that "trickery" introduces other issues in the speaker, such as phase linearity problems. And even then the speaker will still interact with the room, no matter what the manufacturer does to the box, or inside the box. So even though a speaker might have fantastic ruler-flat response in the test lab, it will never behave like that in a real-world room, since the sound leaving the speaker will interact with the walls, floors, ceiling, etc. close to it. This is called "SBIR", for "Speaker-Boundary Interference Response". It's arguably the biggest cause of problems with speakers in rooms. Some people take a very strict view on what SBIR is, while others tend to include all of the ugly artifacts created by putting a speaker in a room. Regardless, SBIR is nasty, and so are all the other artifacts, including baffle step response, comb filtering, phase cancellation, power imbalance, room loading, reflections, diffraction, diffusion, and all the rest. And all that just because you can't put a really large baffle inside a box that you can carry home. But wait! What if you could build a really large baffle and put the speaker in it, after you get it home! Yup: That's what a "soffit" is. If you put your speaker in a soffit, then ALL of those bad things just go away. Gone. Not there any more. No need to deal with. And in fact, you can now "undo" the electronic trickery inside the box, since it is now working against you. You no longer have a baffle step problem, so you don't need the baffle step compensation circuit any more. The power is automatically balanced perfectly by the soffit itself! That's why manufacturers of quality speakers provide a control on the rear panel of the speaker cabinet, so that you can eliminate that. It is usually called "bass roll-off", "bass cut", "room correction" or something like that, and it allows you to reduce the bass power by 6 dB. In reality, it is often a variable control, since the speaker might also be placed in other ways that need only partial reduction in the baffle step compensation, so most manufacturers let you adjust the bass roll-off anywhere between 0 and -6 dB, as needed. So, if your speakers have such a control, then they can be soffit mounted. The only speakers that cannot be soffit mounted easily, are rear-ported speakers, where there is a bass reflex port poking out the back. But front-ported and un-ported speakers can all be soffit mounted. And the results of doing so are well worth the effort! If you want incredibly tight bass response, a crystal clear sound stage, and accurate stereo imaging, and you DON'T want SBIR, phasing, comb filtering, phase cancellation, power imbalance, et. al., then soffit mounting is the way to go.Regarding soffit mounting, is this still applicable for nearfield monitors?
The soffits don't go in the corners: they go in the position where they are needed. You still set up your speakers in the normal way, according to ITU and EBU recommendations, then you design and build the soffits around the speakers.so would soffit mounting the speakers into the corners of this space would place them way too far apart?
Not really. You can soffit mount in a room 2m wide or 10m wide. The issue isn't how wide the room is, but rather where the speakers should be located in that room. Put the speakers at that location, then build the soffits to fit. By the way, the worst possible place to mount you speakers is on top of the console bridge... :) (That last comment should get some comments from some people, I hope! :) ) - Stuart -In which case, I guess width of the space would have to be considerable narrower than 3.75 meters?
Ah, thanks for the additional information regarding the soffits. I guess every implementation I've seen has them in the room corners, so I figured that's where they always go.
I'll have to speak to a carpenter, to see if I could fit them into my budget.
My wife and I are reasearching building materials at the moment, to try and determine the right materials for construction, whilst still remaining within budget.
Assuming a timber stud frame for all of the following, the options we've found so far are:
(floor)
- Poured concrete slab, or
- "Hebel" floor panels (aerated concrete building panels) on concrete footings
(inner surface)
- Plasterboard & regular insulation, or
- "Durra panel" (construction panel made from compressed straw)
(outer surface)
- Colorbond steel, or
- Hebel panels (aerated concrete building panels)
Note that I'm not building a double-leaf wall / room within room here, I just don't have the budget for it unfortunately.
I'd be keen to hear your, or anyone's, opinions of these various construction materials.
skye
True, most do end up there, but that's probably because the soffits are often extended outwards to the side walls, to blend them into the rest of the room better. But it doesn't have to be like that: Take a look at some of John's designs, and you'll see that they don't always have to go in corners. If the room is really wide, then there can be other things beyond the soffits.I guess every implementation I've seen has them in the room corners, so I figured that's where they always go.
At its simplest, it is just a large sheet of very thick wood, with a hole cut in the middle for the speaker to poke through, and some supporting framework behind it. It can be made a lot more complex, sure, and John often combines his soffits with bass traps below, which is a great idea, but it can also be kept simple.I'll have to speak to a carpenter, to see if I could fit them into my budget.
I'm not familiar with Hebel floor panels, but I'd always prefer to have a nice solid concrete base under me. Simple, effective, and inexpensive.(floor) - Poured concrete slab, or - "Hebel" floor panels (aerated concrete building panels) on concrete footings
Once again, I'm not familiar with "Durra panel", so I can't tell you much about it, nor compare it to drywall. However, if you do go with something out of the ordinary, then you are pretty much on your own, acoustically. There's a huge mountain of information freely available on pretty much every possible acoustical aspect of every possible variation on plain old drywall (a.k.a. "plasterboard", "sheetrock", "gypusm board", etc.), from numerous independent sources. There is practically nothing at all on ""Durra panel". A google search for "what are the acoustic properties of "Durra panel"" turned up the grand total of 58 results, half of which link to the manufacturer! A good search for "what are the acoustic properties of "sheetrock"" turned up over 300,000 links. Add in similar searches for "plaster board", "drywall", "gypsum board", etc, and you get closer to half a million links. Versus 58. I think you see why you'd be your own guinea pig if you went with an unknown product! :) Having said that, since isolation is not an issue for you, I guess it doesn't really matter if "Durra panel" turns out to be a really lousy acoustic isolation material for studios. But it does matter if it turns out to have very irregular acoustic absorption properties, like carpet does! That would not be good...(inner surface) - Plasterboard & regular insulation, or - "Durra panel" (construction panel made from compressed straw)
Here to I'm not familiar with either of those, and since: A) it will be in the outer leaf, and B) you don't need isolation, then there probably isn't much in choosing one or the other. It would only make a difference if were to build for isolation, in which case I would say go with whichever product has the highest mass and stiffness.(outer surface) - Colorbond steel, or - Hebel panels (aerated concrete building panels)
Actually, for a few dollars more you really could do that! :) There are a couple of options open to you here: The cheapest would be to put Resilient Channel across your studs, and attach your inner-leaf drywall to that. Same basic principle as "room in a room". The second option is to use RSIC clips and hat channel, instead of Resilient Channel, for a little more isolation. The third option is to use staggered studs for your framing, where you use 2x6 sole plates and top plates with 2x4 studs, alternating every 12 inches, one to the inside, one to the outside. All three of the above accomplish decoupling and creating a good MSM system, which is what you really need. Not that much more expensive, not complicated, and very worth-while. :) - Stuart -Note that I'm not building a double-leaf wall / room within room here, I just don't have the budget for it unfortunately.
Stuart, thanks again for your ongoing help, very much appreciated.
I'm actually quite relieved that you've cautioned me against the more "specialised" (for want of a better word) products, in favour of tried-and-tested methods.
The prices of these products are, as you can imagine, several times more than regular old drywall + stud construction. I guess I was getting carried away with things, good to be brought down to earth a bit :)
So I will look into those three alternative methods for MSM wall construction, they certainly don't look like too much more work/money. I suppose the third option, with the staggered studs, is the preferred method?
Regarding your further comments on external cladding, I'm interested in plain old cement sheeting (called "blueboard" here), rendered for a nicer appearance. Appears to be quite rigid and dense, compared to steel cladding. Not the most glamourous of finishes, but this is a backyard job after all.
Also, with regards to roof space, I have read that the absense of a ceiling (ie leaving the roof trusses and so forth exposed) throws out all the ratio calculations.
I'm interested in leaving the roof space at least partially exposed (for appearances, mainly, and I can fit a ceiling later on if needs be). Any thoughts on this?
Cheers,
Skye
Is that something like fiber-cement board? Comes in panels the same size as drywall, but twice as heavy, and is a grayish color? If so, that will work very well. It is much higher density than drywall (probably around double), but it is a bot more expensive. It's a good choice, though, since you can get away with thinner panels for the same amount of isolation (or the same thickness, for more isolation!).I'm interested in plain old cement sheeting (called "blueboard" here), rendered for a nicer appearance.
Probably, but not necessarily. Depends on the slope of the roof, and other things. But if the roof slope is not too steep, and the overall room shape is still approximately rectangular, then you can use the average dimensions to get a rough idea of modal behavior. The axials for width and length will still be accurate, but the axials for height, plus the tangentials and obliques will not be so accurate.Also, with regards to roof space, I have read that the absense of a ceiling (ie leaving the roof trusses and so forth exposed) throws out all the ratio calculations.
That will blow your isolation plans out of the water! If all you have up there is the roof itself, then your total isolation for the entire room, will probably be somewhere in the mid 20's. Maybe around 25 dB, if you are lucky. That's not much at all. Less than a normal house wall. That depends on the roof itself, of course: it might be a bit higher or a lot lower, depending on how it is built. - Stuart -I'm interested in leaving the roof space at least partially exposed (for appearances, mainly, and I can fit a ceiling later on if needs be). Any thoughts on this?
Yep, that's the stuff. Great to hear it's a good choice. Not the nicest looking finish but can be painted or rendered. Also pretty affordable here, and easy to hang.Is that something like fiber-cement board? Comes in panels the same size as drywall, but twice as heavy, and is a grayish color? If so, that will work very well. It is much higher density than drywall (probably around double), but it is a bot more expensive. It's a good choice, though, since you can get away with thinner panels for the same amount of isolation (or the same thickness, for more isolation!).I'm interested in plain old cement sheeting (called "blueboard" here), rendered for a nicer appearance.
Interesting stuff. As mentioned previously, not so concerned about isolation (honest!). I think we will give it a try with ceiling trusses in place, but no ceiling, and if the acoustical performance suffers I can fit a ceiling in later. Thanks again. SkyeProbably, but not necessarily. Depends on the slope of the roof, and other things. But if the roof slope is not too steep, and the overall room shape is still approximately rectangular, then you can use the average dimensions to get a rough idea of modal behavior. The axials for width and length will still be accurate, but the axials for height, plus the tangentials and obliques will not be so accurate.Also, with regards to roof space, I have read that the absense of a ceiling (ie leaving the roof trusses and so forth exposed) throws out all the ratio calculations.That will blow your isolation plans out of the water! If all you have up there is the roof itself, then your total isolation for the entire room, will probably be somewhere in the mid 20's. Maybe around 25 dB, if you are lucky. That's not much at all. Less than a normal house wall. That depends on the roof itself, of course: it might be a bit higher or a lot lower, depending on how it is built.I'm interested in leaving the roof space at least partially exposed (for appearances, mainly, and I can fit a ceiling later on if needs be). Any thoughts on this?
I've answered your questions inline, to the best of my abilities.
[SPAM SIGNATURE DELETED BY MODERATOR - AND NOTED THAT SPAMMER IS A PARROT!]
Great thread thanks soundman2020! Skye I am also looking at durrapanels which you mentioned for a backyard type studio. FYI soundman, they are using them in lots of large projects listed on their website, but also in cinemas (& iMax) specifically for their acoustic properties apparently. There is a downloadable infosheet on the cinema wall page which contains a graph of sound absortion at different frequencies with a single (50mm) leaf wall, so not completely flying in the dark. They recommend double leaf. Certainly ticks the 'green' box!
http://www.ortech.com.au/durra-panels/durra-panel
cheers
ps I'm not a rep!
Interesting. How does it compare in price vs. 2 layers of 16mm drywall?
The graph is interesting, but doesn't show the actual wall construction or cost, and also the Y axis is marked with unusual units: Do you know how "Sound Reduction Index" relates to the more common "Transmission Loss"? 45 dB at 100 Hz is surprising.
- Stuart -
hey Skye,
I thought i'd add a few bit's of info as I live 'just up the road' from you. Mostly to do with budget. My build is in the final stages and is not much larger than yours and has come in at around 50K and that's with me doing the majority of the work myself all the way from excavation, concrete, carpentry, plastering etc. I understand that you don't need the isolation of a 'tracking' room and the neighbours aren't an issue, but I don't think 10K will get you there unfortunately.
I'd guess the concrete slab alone is in the 4-5k mark if you're getting a contractor to do it. Maybe 2.5K for a carpenter to do the external frame and trusses. Add 1.5K for the trusses themselves, and another 2-3K for a roofing plumber to do the roof and gutters and you're probably at around 10K. You still need external cladding and electricity before you can be weather proof and plug in any gear and even then you're basicaly in what will be a very cold shed.
I wonder whether a pre-fab steel shed is the go. The concrete slab doesn't have to be as industrial for one of those as it does for a 'normal' building. You might be able to get the shed and slab done for around 5K which would leave you with 5k to play with for electrical, heating/cooling, insulation and maybe even some internal acoustic treatment.
And just so you know, I put my build budget at 25K when I started :roll:
Ah, so it's been a while (a baby in your life will do that, I've found!) but this project is definitely still on the cards.
I'll take a moment to say thanks to all who have offered their invaluable insight, especially Soundman2020 and stevev (good to hear there's a local here, would love to check out your build some time).
stevev, I have come to realise that my original budget was indeed hopelessly optimistic :)
Anyway I had a meeting with a draftsman recently who gave me a rough estimate more than my original budget, but less than your spend, and definitely doable.
Anyway my next question is regarding flooring. I understand that a concrete slab is the preferred approach, to avoid the resonant drum effect.
However, I am a little concerned about freezing to death - as my fellow Central Highlander will attest, it's been a frosty winter in these parts, and the idea of sitting on a refrigerated block for 12 hrs a day is less than appealing. My budget definitely won't stretch to in-floor heating, the family home gets preference over that!
A friend (who has done a lot of building, albeit not sound studios) suggested a plywood floor on brick footings, but glueing several layers of marine ply (and perhaps blueboard/cement sheeting) for rigidity/density. Is this a viable option? Just how many layers would you have to glue to get something that won't rattle and ping like a drum?
And while I'm at it with the questions - stevev, if you're around, how did you go about heating your studio?
Thanks again, and cheers,
Skye
Hey Skye, congratulations on that "baby in your life "!!!! Yup, they certainly do seem to have an effect on your plans... not to mention your sleeping schedule... :)
Excellent! A realistic budget is a key part of building a studio. and the general rule here is to take your original budget, add yesterday's date, multiply by a random number between 2 and 50, divide by a small fraction, then add a zero on the end, just in case. That normally gets you close.... :lol: :) :D :) :roll: :!: More seriously, I'm sure your draftsman has a better grasp of costs than most people, but if he hasn't done a studio before then he's probably still underestimating a bit. There are "things" and "techniques" in studio design that aren't done the same way as for a typical house, office, shop or school. So I would add about 10% to 20% on top of what he suggested, and you'll probably be in the ball park. Not trying to scare you! Just being realistic.Anyway I had a meeting with a draftsman recently who gave me a rough estimate more than my original budget, but less than your spend, and definitely doable.
Then I would suggest a suitable laminate wood flooring on top of the concrete, fairly thick, with a good thermal underlay, also fairly thick. The underlay will probably be something like 5mm, and the laminate flooring about 10 mm or so. That doesn't sound like much, but unless you live at the south pole, it should be more than enough. The HVAC system will take care of keeping the room air at the right temperature and humidity, so the room will feel just fine and comfortable.I am a little concerned about freezing to death - as my fellow Central Highlander will attest, it's been a frosty winter in these parts, and the idea of sitting on a refrigerated block for 12 hrs a day is less than appealing. My budget definitely won't stretch to in-floor heating, the family home gets preference over that!
Math time! The density of concrete is about 2200 kg/m3, so a 15 cm (6") slab will weigh about 330 kg/m2 (68 PSF). The density of marine grade plywood is about 500 kg/m3, so in order to get the same surface mass as for a concrete slab (330 kg/m2), you would need to make it about 66 cm (26") thick, which works out to about 34 layers of 19mm (3/4") plywood.... :) :shock: The numbers don't lie.... :wink: It's not about "rattling and pinging", but rather about the resonance of a lightweight floor suspended over a cavity. ALL materials have a natural resonant frequency, which depends on several things but is mostly related to the mass (surface density, linear density, etc.). If you hang a mass on a spring, then you create a second resonant system the resonates at a frequency defined almost entirely by the mass and the "resilience" of the spring. A floor suspended over a cavity is exactly that: The floor itself is the mass, and the air in the cavity is the "spring" (we don't usually think about air as being "springy" from our point of view as humans, but for sound waves it sure is!). So you have two resonances going on there: that of the floor material itself, and the much greater resonance of the tuned "mass-spring" system. The "tuning" is set by two things only: the surface density of the floor (kg/m2) and the depth of the air cavity. Increase either of those, and the resonant frequency goes down. Resonant theory says that in order for that to not be a problem in your studio, you need to get the resonant frequency down below 1.414 times the lowest frequency of interest. In reality, that's not good enough, and you have to get it down to no more than half the lowest frequency. So if you want to isolate the entire audible spectrum (20 Hz to 20 kHz), then you need to get a resonant frequency of under 10 Hz. That's pretty hard to do, unless you use very massive materials, or very large air gaps. If you are interested, the equation for calculating the fundamental resonant frequency of a panel by itself is: Fr = 0.45 * vL * b[(1/l)^2 + (1/h)^2] where b is the panel thickness (meters), l and h it's length and height (meters) and vL is the longitudinal velocity of sound in the partition (m/s) given by vL = [E / (p * (1 - s^2))]^1/2 [where E is Young's modulus of elasticity, s is it's Poisson ratio and p it's density]. (It gets a bit complex...) Fortunately, the equation for calculating the fundamental resonant frequency of such a floor is very simple: F = 60 / SQRT (M * D) Where M is the surface density (kg/m2) of the floor materials, and D is the depth of the air cavity in meters. (The number 62 is a constant that encompasses things like air density, air temperature, the speed of sound in air, those other weird terms above, and a few other things that don't change much.) So for a single sheet of 19mm plywood over a 10 cm cavity (depth of a 2x4), the frequency would be about 67 Hz. Add another layer and it goes down to about 46 Hz. Add two more layers (total 4 layers) and it goes down to 32 (can you say "bass guitar"). Add ANOTHER 4 layers (total of 8!) and it is down to 21 Hz. Add another 8 layers, (total 16!!!), and you get down to 15 Hz. Finally double that lot (32 layers now....) and you get down to 10 Hz. Bingo! But watch that step at a the edge, as you walk out the door! :) OK, so you could use a deeper cavity and less mass, but it's still not much fun: for a 20cm cavity (2x8 joists) you could get by with just 19 layers of plywood on your floor, and for 30 cm depth (2x12 joists), you'd need a paltry 13 layers. Bigger joists? Sure. Let's try massive 20" joists (50 cm). Much better! You only need 8 layers now!!! :shot: :!: That's why I just have to giggle a bit when I see those knuckleheads over on YouTube frantically "floating" their floors on 2x4 studs with a couple of layers of thin plywood on top, and swearing that they are doing Something Incredibly Useful for their room.... If only they would do the math.... sigh! :roll: On the other hand, a concrete "slab on grade" (poured directly on top of Mother Earth, with a waterproof membrane, of course, and probably sand/gravel too) is the best darned floor you can get for a studio. Best in terms of isolation, and also for actual room acoustics. You have the mass of the concrete, no air gap at all, and the entire planet acting as damping! It's hard to improve on that!!!! - Stuart -Just how many layers would you have to glue to get something that won't rattle and ping like a drum?
Thanks again for the great info Soundman2020, and the maths lesson :)
I was fairly convinced that the general consensus would be "stick with concrete slab", but just wanted to get some advice on possible alternatives.
I'll look into the laminate flooring.
FWIW, at least in the medium term I will not be installing a full HVAC system - I just don't have the money for it, and can't justify the expense as this is a personal project studio, not a commercial venture. And besides I cannot stand air conditioners! Ventilation will be provided the "old fashioned" way.
I realise this is less than ideal for acoustical reasons, but that's what I have to work with. I've made a lot of great mixes in non-sealed rooms, so I'm going to have to work with it.
Another question, about windows this time (to the outside world, not a "studio window").
I would very much like a window to the outside - the regular studio cave with no natural light makes me shudder! I like natural light and I like to be able to see outside.
I realise that regular glass has virtually no isolation properties, and I will be punching a great big hole in my sound blocking walls. But I'd still like to ask after any advice you or others may have (apart from "don't do it!") -keeping in mind that isolation *is not an issue* - only acoustic integrity.
Cheers,
Skye
Well, I'd really suggest that you think this through a bit more: a lot of people who come to the forum start out with that same idea about HVAC, but once they start getting into the design, they realize that it's not a luxury: it's a basic necessity. You need to maintain a fairly constant temperature in your rooms, and more important, you need a fairly constant humidity. Equipment, mics, and instruments are sensitive to both temperature and humidity. Some condenser mics, for example, are especially sensitive to these, and their frequency response changes as the condition changes. Even if you never plan to record anything acoustic in your studio, ever, and only mix, your equipment still need ventilation at more or less constant temperatures, and you yourself have this terrible habit, called "breathing"! You sort of need to do that several times per minute, and you need to have oxygen in your air to stay alive, so it's probably useful to bring in fresh air. And since you also exhale moisture, along with CO2 and other nasty things, it's probably a good idea to provide a path for those to leave the building... But this doesn't need to be complicated: a simple mini-split system on the wall for keeping the temp and humidity under control, plus an inlet duct to bring in fresh air, and an exhaust duct to take out stale air, with a small, quite fan in the exhaust duct... Done.at least in the medium term I will not be installing a full HVAC system - I just don't have the money for it, and can't justify the expense as this is a personal project studio, not a commercial venture. And besides I cannot stand air conditioners! Ventilation will be provided the "old fashioned" way. I realise this is less than ideal for acoustical reasons,
It's not a problem to put windows in a studio. Most studios have windows between rooms, so the engineer and artists can see each other, and some also have windows to the outside world.I would very much like a window to the outside - the regular studio cave with no natural light makes me shudder! I like natural light and I like to be able to see outside. I realise that regular glass has virtually no isolation properties, and I will be punching a great big hole in my sound blocking walls. But I'd still like to ask after any advice you or others may have (apart from "don't do it!") -keeping in mind that isolation *is not an issue* - only acoustic integrity.
You keep saying that, but here too you might want to re-think: I mentioned before about things like wind, rain, hail, aircraft, cars, people, etc. Even if you only ever mix in there (never record), it's still annoying to have to go back over something several times because you though you heard a problem with the hi hat, but it turned out to just be the wind outside... or you though you heard something wonky in the bass guitar... but it was just a distant helicopter flying past... or you thought you heard voices in the mix, but it was just someone talking outside... Etc. Speaks the voice of experience: been there, done that! It's annoying, and slows you down. And of course, if you DO plan to record in there, then "no isolation" isn't really an option. But from what you've been saying about the materials you are thinking of using, you should be able to get pretty decent isolation. - Stuart -keeping in mind that isolation *is not an issue*