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PostPosted: Fri Dec 02, 2016 3:34 pm 
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Location: Apollo Bay, Australia
I’m in the early stages of planning a new freestanding studio on a property I’ve just purchased in Apollo Bay (on the southern coast of Australia). This is a major dream come true, especially after my previous attempt to build a studio extension onto my suburban house was halted due to council restrictions. (If curious, here’s the previous thread for the build that never happened: viewtopic.php?f=2&t=19992).

But now I have 7 acres to play with and the most incredible views. It's an elevated and mostly flat block with ocean views in front and rolling hills behind. No neighbours within 300 metres. Here’s the view from the back yard.
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I’ve spent hundreds of hours in this forum and pouring over books on studio design and construction but I’m sure I’ll still have a multitude of questions to ask over the course of this build. I don’t even move to the new property until February 2017 but I want to start planning early. At this stage I've gotten myself a bit mentally muddled over room sizes.

The main purpose of this studio is to give me a really comfortable, quiet and inspiring space to compose and mix in. I’m a professional composer / self-produced artist, and I mostly create relaxation music and some inspirational cinematic music. 95% of the time I do this with virtual instruments but I will do more live recording in this new studio. I’ll occasionally record voiceovers, singing, and acoustic instruments like flute, acoustic guitar, violin, cello, Tibetan singing bowls and perhaps some ethnic percussion. I won’t be recording any bands, drums or amped guitars. This space is mostly just for me and I’ll only open it to customers on an invitational basis.

By the way, my budget for the build is up to $150k AUD. I’m planning on a structure with a footprint of around 70 - 80 square metres. Control room, 1 tracking room, a foyer/airlock, a little storage and a loo.

Most studio designs I see tend to have a moderately sized control room and a larger live room (with additional rooms added as necessary). My approach is a bit opposite. I’d like to have a nice spacious control room for me to compose and mix in – around 5m x 8m x 3m (approx. 16 ft x 26 ft x 10ft). I really want some room to move around a bit and space for couches to relax on. I’d also like to have a smaller vocal booth / recording room of around 3.5m W x 4m L x 3m H. While I’d love to have a nice big an ambient space to record acoustic instruments in, I don’t think I can justify the cost of dedicating that much space to recordings I might only do a handful of times a year. So my plan is close mic most instruments in the smaller room and use reverb to add space.

Questions:
1. On the face of it does my 2 room combination make sense in light of what I want to use it for?

2. While I plan on using the smaller room for most recording, I really like the idea of recording some performances in the larger control room. I’ve read many opinions on the pros and cons of doing this, for example, it’s great for communications with the musicians, but less than ideal from an acoustic perspective. Is it possible to set up a room of this size (5m x 8m) to be a good sounding space for mixing at one end and still be a good space for recording towards the other end? Perhaps a more dead acoustic at the mixing end of the room, and more diffuse acoustic at the other end? In other words, can I achieve a good sounding multi-purpose space or am I going to be fighting a battle of conflicting priorities?

3. General question- Assuming good acoustic design, how big does a room need to be before it can deliver a pleasing and useful amount of ambience and character to acoustic instrument recordings? I know there might not be a simple answer to this question, but any comments you care to offer will interest me.

4. Often when I look at control room designs, the ceiling and many of the walls are angled (symmetrically) in various directions. At the same time, I’ve read forum comments from respected acousticians who say that rectangular rooms can sound great and that angled walls/ceilings aren’t really necessary. Apparently they don’t remove room modes, they just help eliminate reflections, which is something you can accomplish with acoustic treatment. Is this true? Are there other reasons why I so often see funky corners and wall angles in control rooms?

Thank you very much for your help at this early stage of the project.

Chris


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PostPosted: Sun Dec 18, 2016 2:51 am 
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Welcome back, Chris! :thu:

Wow! That's a really beautiful looking location. Very, very nice.

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I’ve spent hundreds of hours in this forum and pouring over books on studio design and construction
Great! so you are just in the initial stages of commencing the beginning of the feasibility of maybe getting started! :) Well, to me at least, that's how it feels sometimes... after doing all that, and still having headaches trying to put it all together and make it work...

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but I want to start planning early.
Very smart move. It takes time. And getting your design complete on paper before you ever lift a hammer is the key to getting it right.

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At this stage I've gotten myself a bit mentally muddled over room sizes.
Then you most certainly are a fully qualified studio designer! That's one of the signs that you are doing it right...

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This space is mostly just for me and I’ll only open it to customers on an invitational basis.
OK, that's useful to know. A commercial studio for rent needs some things done different than a personal, private studio.

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By the way, my budget for the build is up to $150k AUD. I’m planning on a structure with a footprint of around 70 - 80 square metres. Control room, 1 tracking room, a foyer/airlock, a little storage and a loo.
That sounds like a good plan, with a decent budget. My customers in Australia report that it costs them around $ 1000 - 1500 per square meter to build a studio, so you are certainly on track for that.

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Most studio designs I see tend to have a moderately sized control room and a larger live room
There's a reason for that. The reason is "reverb tails". Your control room has a carefully tuned acoustic environment that is flat and neutral, and ad hoc for the actual size of the room. ITU BS.1116-2 is a good spec to use for that. So the decay time in your control room will likely be around 250 - 350 ms. This is sometimes called "RT60" time, but that's not strictly the correct name. That's the time that any given sound will take to die away from it's peak to a level 60dB lower. That's what you need for a control room, and the exact decay time is set by the volume of the room (cubic meters). Smaller control rooms have shorter decay time, larger rooms have longer times.

So far so good.

But if your live room is smaller than the control room, it will have a decay time that is shorter! So if you record something in your live room, and the decay time of the live room is shorter than that of the control room, you will never hear the "reverb tails" in the control room! Since sound dies away faster in the live room than it does on the control room, you will never be able to hear how that sound is dying away, so you won't be able to mix it properly: you can't sculpt sounds that you can't hear! And even though you won't be able to hear them in the control room, other people WILL be able to hear them under some circumstances. For example, the average car will have an even shorter decay time, so people listening to your music in their cars will hear things that you never heard: Ditto for people listening on ear buds hooked to their iPhones, or on headphones, or when your music is played out in the open air, where there is no decay time at all. In all of those cases, the listeners will be hearing stuff that you never heard, and never mixed. It is still there, even though you didn't hear it.

This is subtle, yes, and perhaps not noticeable to most people, but if you are investing 150k in your own personal studio, I'm sure you want it to be fantastic, and not turn out music that sounds different when played elsewhere.

In order for your LR reverb tails to be audible in the CR, the LR needs to be much larger (bigger volume).

You might think: "Well then, I'll just make the CR more dead! I'll tune it to have very short RT60, so I can hear my live room!"... And that would be a big mistake. Firstly, dead rooms are uncomfortable to work in for ling periods. They are mentally tiring, and a little unpleasant. If you ever have the chance, go sit inside an anechoic chamber for a few minutes to see just how disorienting a perfectly dead room is: It sounds really cool, for the first few minutes, ... but pretty soon your brain start trying to hear things that it is used to hearing, everywhere else you go on the planet, but there's just nothing there to hear. It's not so nice, after a while. That's the extreme case, and your room certainly won't be an anechoic chamber, but it does show why a dead room is not nice to work in.

There was a studio design concept back in the 70's and 80's known as "LEDE" for "Live End Dead End", which basically had the engineer surrounded by a dead environment, with a more live environment behind that. It was great, in theory, but engineers found it unpleasant and fatiguing to work in those rooms for long periods. The concept was abandoned, or rather modified, so these days we have specs, like ITU BS.1116-2, that define who a room should sound for critical listening, to be clear, accurate, precise, not tiring, etc. And we have control room design concepts, based on that spec, such as RFZ, NER, CID, MR, and other similar ones. Rooms built like this are excellent, acoustically, and also pleasant to work in. RFZ rooms, for example, give you perfectly clean, clear, neutral, flat, direct sound direct to your ears, with zero coloration from the room itself, plus a gently, diffuse reverberant field that dies away at the perfect rate.

On this thread, you can see what the acoustic response of a properly tuned RFZ-style room should be: viewtopic.php?f=2&t=20471

Sorry about the rant! But that's the reason why live rooms are bigger than control rooms: so you can hear what the instrument really sounds like in that room. Not so important for vocals, but for things like "flute, acoustic guitar, violin, cello, Tibetan singing bowls and perhaps some ethnic percussion" you will absolutely and definitely want to hear their natural sound in the natural decay of the live room, which needs to be big enough to provide a nice long, warm, clean reverberaant field, to complement the instrument. Yes, you can add artificial reverb later in the mix, but I'm a bit of a purist myself, and I if I'm going to go to all the trouble recording the perfect sound of a natural acoustic instrument, I want to sound ... well... natural and acoustic!

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While I’d love to have a nice big an ambient space to record acoustic instruments in, I don’t think I can justify the cost of dedicating that much space
It's not "space" that you need, in terms of floor area. It is "volume". Your control room could have a normal height ceiling, but your live room could have a much higher ceiling, and therefore greater volume for the floor area. You should be shooting for an RT60 time of at least 2 to 4 times that of the CR, so if your CR has a decay time of, for example, 250 ms, then you would probably want the LR to have a decay of maybe 650 ms or so, perhaps as much as one second.

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So my plan is close mic most instruments in the smaller room and use reverb to add space.
To my way of thinking, a close mic'd violin with artificial reverb doesn't sound as natural as a violin recorded in a nice acoustic space with a more distant mic that captures the room ambiance as well as the direct sound. But that's just me. Others might have a different opinion. I have just never seen the point in recording an acoustic instrument, then killing all the acoustics and reconstructing the sound artificially. The end result is no different than just using a violin synth on the keyboard or in the DAW.

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1. On the face of it does my 2 room combination make sense in light of what I want to use it for?
I think I already covered that! :)

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Is it possible to set up a room of this size (5m x 8m) to be a good sounding space for mixing at one end and still be a good space for recording towards the other end? Perhaps a more dead acoustic at the mixing end of the room, and more diffuse acoustic at the other end?
You mean like a "Live End Dead End" sort of thing: 8) :shock: :roll: See above... That was tried a few decades ago, then abandoned, for the reasons I outlined.

Here's the issue: the entire purpose of a control room is so that you can hear the perfect pristine sound coming from your speakers, without the room adding to that or taking away from it in any way. The room must do nothing at all to that sound: it must be totally neutral. This is very logical , and very obvious, when you think about it, but too many people get sidetracked on wanting their control room to "sound good". Wrong! it must not "sound" like anything! It must sound like it isn't even there. It must not interfere in any way with the sound that comes out of the speakers. The only thing it must do, is to convey that sound straight from the speakers to your ears, purely, cleanly, and unadulterated.

It also needs to take the sound that went past your ears, and turn that into a neutral, clean, diffuse background field that dies away naturally, at just the right right to keep your brain content, such that it does not even notice. If the decay rate is too high or too low, your brain "notices", and tries to tell you things about the direct sound that just are not true. this is the field of "psycho-acoustics", which is how our ears and brains perceive the sound, as opposed to the way the sound actually is. There are certain things that can screw up our psycho-acoustical perception of sounds. For example, if a reflection of the direct sound arrives at your ears with a time delay of less than 20 ms and at roughly the same level, then your brain is not able to process that as a separate "echo" of the original sound. It happens to fast for your brain to be able to "integrate" that. Instead, your brain interprets that as a sound that had a different frequency spectrum and came from a different direction! So you will hear that as a very slightly out of tune, sound, that came from a direction that is not where it really came from. This is due to the way your ear works, and the interference patterns, comb filtering, phase-changes, and other minute things that happen inside your ear canal, as the reflected wave combines with the direct wave.

This is why one of the key specs for a true RFZ-style room is that the room must not allow any reflections to get to your ears within a window of 20 ms, and everything that does get to your ears after 20 ms must be at least 20 dB quieter, then die way to 60 dB quieter at the correct rate for that room size.

So, to answer your question: Can you tune a CR such that it the acoustics are perfect for a CR and also perfect for an LR? The answer is no. Except perhaps for vocals. Acoustic instruments like a warm, live environment to sound good, but "warm" and "live" automatically implies that it is NOT "flat" and "neutral" :) It is impossible to have a room that is both "warm" and "flat" at the same time. And just as impossible to have a room that is both "live" and "neutral" at the same time.

Yes, you can compromise, and create a room that is almost good enough to be a CR and also almost good enough to be an LR, but I would ask: WHY? Why would anyone do that? You'd have a room that isn't really good for either!

If all you want to do is record vocals in your CR, then yes, that can work: Maybe even acoustic guitar. But I'd never try to record violin, cello, or any percussion in a CR.

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In other words, can I achieve a good sounding multi-purpose space or am I going to be fighting a battle of conflicting priorities?
There is just one way of doing this, and that is to make the acoustic signature of the room, variable. Have panels that can be opened, closed, slid, flipped, rotated, etc. to change the acoustic response of the room. So with all of the panels in one specific arrangement, the acoustic response would be that of a CR, and by changing various panels in various ways, you could make it more live, more diffuse, more specular, warmer, harsher, or whatever else you wanted. But within limits! There still wont be a large range of acoustics available for you. Of course, that adds expense and complexity. I have done a few rooms with variable acoustics, but only rooms that were intended to be live rooms anyway. Rooms where the studio owner wanted to be able to change the sound subtly to adapt it for different scenarios. I have not yet done that in a control room (although I am talking to a potential customer about doing that at present).

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3. General question- Assuming good acoustic design, how big does a room need to be before it can deliver a pleasing and useful amount of ambience and character to acoustic instrument recordings? I know there might not be a simple answer to this question,
Let me answer your question with another question: "How long does a piece of string have to be before it is useful?". And another one: "How big does the engine in a vehicle have to be, before it is a good size?"

:)

Right. There is no simple answer. There are different needs for different situations. What sounds great for a grand piano, will sound pretty bad for an acoustic guitar. What sounds great for vocals is terrible for drums. What sounds great for a flute is terrible for bass guitar. What sounds great for growling, screaming electric guitars is terrible for a cello. etc.

The general rule of thumb is that the CR should have a floor area of about 20m2, and the LR should have a volume that is 2 to 10 times larger, or as large as is needed to fit in all the musicians and their gear.

For your place, I would suggest going with a slightly smaller CR than you were talking about, say around 4x7m, x3 high, and a live room of maybe 6x8m, and at least 4 m high. That would be a nice sized CR, and the LR would have a volume of about two and a half times the CR. Yes, that's a little larger in total than you mentioned for your footprint, and adding the lobby, storage and loo would probably take ti around 90m2 or so, but you do have the budget to do that. Or you could shrink the rooms a little and come in around 80m2, while still retained a spacious CR and good acoustics. There are lots of tricks for making this work out well, even in a smaller space.
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4. Often when I look at control room designs, the ceiling and many of the walls are angled (symmetrically) in various directions. At the same time, I’ve read forum comments from respected acousticians who say that rectangular rooms can sound great and that angled walls/ceilings aren’t really necessary. Apparently they don’t remove room modes, they just help eliminate reflections, which is something you can accomplish with acoustic treatment. Is this true? Are there other reasons why I so often see funky corners and wall angles in control rooms?
Yes. No. Definitely. Never. Maybe. Always. Possibly. Sometimes! :)

OK, let me rant again! It works like this: it all depends on what design concept you are following. There are several good ones, and each has a slightly different approach.

Yes, you can have a purely rectangular room that sounds fantastic... if it is large enough, carefully dimensioned, carefully laid out, and suitably treated. On the other hand, a rectangular room with a bad relationship between the dimensions, or poorly laid out, or with the wrong speakers, or badly treated, will sound awful! If it is designed fully in the hands of an expert designer, then yes, rectangular is fine. For example, all of the rooms in Abbey road are rectangular...

However! There is an underlying issue related to speakers. If you have speakers inside a room, the speaker and the room interact to cause interference patterns, and every location inside that room then sounds different from every other location. The reason is "SBIR". Speaker-boundary Interference Response. There will be reflections off every wall that interfere with the direct sound from the speaker, causing phase cancellations at different points in the room, for different frequencies. The worst offender here is the phase cancellation caused by the front wall, because it causes a monstrous dip in the frequency response at a point in the spectrum that is smack bang in the middle of the low end. So it kills some frequencies in a comb-filter pattern that extend up through the entire spectrum. In addition to that problem there are issues such as edge diffraction and power imbalance caused by simply having the speaker inside the room, close to the front wall. There is a very simple way of curing this: take the speaker out of the room! Mount it inside the front wall, such that the front face of the speaker is flush with the front wall. Magically, all of those issues go away completely. There is no more SBIR, phase cancellation, edge diffraction, comb filtering, or power imbalance caused by the front wall, because the sound coming from the speaker no longer "sees" the front wall: In effect, the speaker isn't even there, as far as the front wall is concerned, and the front wall isn't even there, as far as the speaker is concerned.

So great! Just mount your speakers in the front wall! But there's a problem... the speakers need to be angled to point at your ears. They can't be flat in the wall. Simple solution: build angled walls to mount the speakers in! And that's the basis for the RFZ room design principle: Build angled sections on each side of the front wall, and put the speakers in those. This is sometimes called "soffit mounting", but isn't really the correct term... but that's what everyone calls it, so "soffit mount" it is!

With RFZ (which is my favorite way of designing rooms), you also angle some other surfaces in the room, to ensure that not only do you not have any front-wall artifacts from the speakers, but also that all of the reflections that would have reached your ears from the side walls and ceiling, are deflected off in other directions, such that they do not ever reach your ears, until at least 20ms after the direct sound did, and even then that they arrive diffusely, and at a level that is at least 20db down from the direct sound.

That's the reason for angling walls. When done correctly, as part of an RFZ-type design, the results are astounding. In my opinion, soffit-mounting your speakers is the biggest single thing you can do to make a room great.

Angled walls don't remove modes, but they do control reflections, which is arguably even more important. They can also eliminate flutter echo, even though I would never a angle a wall for that reason alone, since flutter echoes can be dealt with simply, using either diffusion or absorption panels at strategic locations.

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Are there other reasons why I so often see funky corners and wall angles in control rooms?
Yep! In a well-designed control room you will very often see that, and those funky angles are there to control the reflections around the engineer's head, such that he never hears them, and only hears the direct, pure, clean sound of the speakers.

if you are serious about having the best control room you can, then I'd urge you to consider doing it as an RFZ room. There's nothing better, IMHO.


- Stuart -

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PostPosted: Fri Jan 13, 2017 3:05 pm 
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Thank you so much Stuart. It's been a few weeks since you replied but your words have been rolling around in my mind ever since then.

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My customers in Australia report that it costs them around $ 1000 - 1500 per square meter to build a studio, so you are certainly on track for that.

Initial discussions with builders and a couple of real estate agents in the area indicate that prices are closer to $2,000 per square metre. It's a rural location and so the cost of labour and many common building materials (like concrete for example) are higher than in the city. I'll know more once I start discussions with the architect and builders.

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...Sorry about the rant! But that's the reason why live rooms are bigger than control rooms: so you can hear what the instrument really sounds like in that room. Not so important for vocals, but for things like "flute, acoustic guitar, violin, cello, Tibetan singing bowls and perhaps some ethnic percussion" you will absolutely and definitely want to hear their natural sound in the natural decay of the live room, which needs to be big enough to provide a nice long, warm, clean reverberaant field, to complement the instrument. Yes, you can add artificial reverb later in the mix, but I'm a bit of a purist myself, and I if I'm going to go to all the trouble recording the perfect sound of a natural acoustic instrument, I want to sound ... well... natural and acoustic!
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To my way of thinking, a close mic'd violin with artificial reverb doesn't sound as natural as a violin recorded in a nice acoustic space with a more distant mic that captures the room ambiance as well as the direct sound. But that's just me. Others might have a different opinion. I have just never seen the point in recording an acoustic instrument, then killing all the acoustics and reconstructing the sound artificially. The end result is no different than just using a violin synth on the keyboard or in the DAW.

I really take your point and in all honesty I'd love to take your advice quite specifically and build a 6m x 8m x 4m live room (or larger) but given the fact that this could cost me $100K, I better be sure I'm actually going to use that space often enough to justify it!

Most of the time I compose music with sampled instruments. For example, if I need a grand piano in a great space, I might use the Garritan CFX concert grand plugin. 300GB of super detailed samples of a Yamaha CFX, expertly recorded with multiple mic positions at Abbey Road Studios. Playing it is a dream and while I do miss out on the experience of recording a real piano, the end result is usually very satisfying.

I've had to think long and hard about what I really need and how I intend to use it, and I guess that's the first and most important step in any studio design. I'm a composer first and foremost. I LOVE mixing and love having a good listening environment. I'm not a professional recording engineer though. So how often will I record live flutes or cellos? I like the idea of doing it often but if I am honest with myself it might only happen 2 or 3 times a year. Can I truly justify the cost of a large live room? More and more it is starting to seem like a big luxury rather than a necessity.

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If all you want to do is record vocals in your CR, then yes, that can work: Maybe even acoustic guitar. But I'd never try to record violin, cello, or any percussion in a CR.

At the end of the day, a quiet control room in which I can compose and mix is the number one priority. Given that I can probably also record vocals and voiceovers in that space, a one-room design is starting to become more appealing to me. Reality is knocking and it's saying, "this is a composer's studio, not a 'recording' studio".

If the time comes when I want to start recording live instruments on a regular basis (either for myself or for other artists) and if my business is going really well, then I would consider adding on a proper live room (or rooms). There's no shortage of space in my new location so possible future extensions will always be feasible.

Regarding room shapes and RFZ designs. I won't re-quote everything you wrote. Suffice to say that you answered all my questions really well and pretty much sold me on a RFZ design.

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In my opinion, soffit-mounting your speakers is the biggest single thing you can do to make a room great.

I'll definitely keep that in mind. I'm using Event Opals at the moment which would be a bit tricky to soffit mount given their slightly ovular shape. I'm also considering Focal SM9's as a future addition and these can't be soffit mounted either.

Thanks again for all your help so far. I'm moving in to the new place in 4 weeks and I'm super keen to get things started. :yahoo: :yahoo: :yahoo: Will update this thread as progress is made.


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PostPosted: Wed Jan 25, 2017 12:59 am 
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My customers in Australia report that it costs them around $ 1000 - 1500 per square meter to build a studio, so you are certainly on track for that.


Initial discussions with builders and a couple of real estate agents in the area indicate that prices are closer to $2,000 per square metre. It's a rural location and so the cost of labour and many common building materials (like concrete for example) are higher than in the city
Wow! It sure is getting expensive to build where you live. Are there any locally available building materials that are less expensive? For example, can you get things like drywall (plasterboard), MDF, OSB, plywood, fiber-cement board, concrete blocks, bricks, and suchlike at more reasonable prices? It might be worthwhile looking into those things, and also checking how houses are typically built in your area. It is certainly possible to build a great studio that isolates very well and performs wonderfully, using those materials.

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I've had to think long and hard about what I really need and how I intend to use it, and I guess that's the first and most important step in any studio design
Absolutely! That's exactly the way I approach a design for my paying customers: first try to understand as completely as possible what they really need, and how they normally work, and how a typical session goes, what they will be doing in the studio every day, then design it around that. Understanding the purpose of the studio is the most important part of the design process: even more important than the make and model of speakers that will be used, or the console, or the DAW, or the list of outboard gear. It's a lot easier to modify the design to accommodate different speakers, than it is to modify the design to add a new vocal booth, drum room, machine room, etc., or to take switch over from being a private personal studio to being a commercial studio, or to switch over from being a rock and pop music studio, to being a classical music studio, or to make any of those into a studio for ADR, Foley, or film work. The very first thing you should do when you start designing your studio, is to fully identify WHY you want it, and HOW it will be used. If you get that wrong, then the chances are it won't work out at all well! It would be like deciding you want to go on vacation, but not identifying if your destination is the beach, the mountains, the big city, or the jungle... :)

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I'm not a professional recording engineer though. So how often will I record live flutes or cellos? I like the idea of doing it often but if I am honest with myself it might only happen 2 or 3 times a year. Can I truly justify the cost of a large live room? More and more it is starting to seem like a big luxury rather than a necessity.
Other questions I would ask: Do you often invite friends, family and other musicians over to just jam a bit, make music together, have fun, practice, rehearse, or work together on a song? Is there a another large studio close to where you live, where you could easily record your flutes, pianos and other live instruments when needed, or would that involve a trek to a more distant location? Do you personally own a lot of musical instruments that you play regularly, ether for your work or just for pleasure? Does anyone in your immediate family or your close group of friends and acquaintances own / play such instruments? Are there any other activities you do (apart from making music) where a nice sized room that sounds good might be useful? For example, if you often entertain, or are a member of some type of club, church, or other organization that needs a place to meet? Are there any other uses that you can think of for a large room in any other of your activities?

Just some ideas to get you thinking "out of the box" on the need, otr lack of need, for a live room.

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At the end of the day, a quiet control room in which I can compose and mix is the number one priority. Given that I can probably also record vocals and voiceovers in that space, a one-room design is starting to become more appealing to me. Reality is knocking and it's saying, "this is a composer's studio, not a 'recording' studio".
OK, cool! That's a good start. If recording in the CR is something you would want to do, then that starts to shape the way the CR should be designed, and some of the specs. Number one, you'd need an NR (or NC) of 15 or lower, which pretty much defines that you will need a separate small "machine room" to put all your noisy equipment in: DAW, disks, tape decks, or anything that has a fan or makes any type of audible noise. You cannot have that stuff inside the CR if you plan to record in there. That also implies extra care with the HVAC isolation. Air noise, HVAC fan noise, compressor noise, etc. are all things that will need to be carefully controlled in your HVAC design. That implies large ducts with high volume of air flow at low speeds, large silencer boxes with multiple baffles, keeping the AHU (ERV?) completely outside the isolation shell, and a several other things.

HVAC is probably the most overlooked part of a studio. Many people never even consider that HVAC is a major part of a studio, and that HVAC is noisy...

Quote:
If the time comes when I want to start recording live instruments on a regular basis (either for myself or for other artists) and if my business is going really well, then I would consider adding on a proper live room (or rooms).
If you do think that is a serious possibility in the future, then you need to plan for it now! Since your studio must work together harmoniously, the relative locations, access paths, sight lines, cable runs, and many other aspects need to be planned for now. For example, if you do plan to have a live room in the future, then you need to ensure that it will be easy to create the very necessary sight lines between the mix position and the live room, such that the engineer and musicians can see each other while tracking. You also need to ensure that there will be easy access between the CR and LR, so you can move back and forth between them when setting up mics, instruments and people. So no long corridors, multiple doors, tight passages, etc. If you will be recording other musicians, then you also need to ensure that there is easy load-in, load-out access for the equipment and instruments they bring with them. For example, if you do think you'll be recording grand piano, then there needs to be a ramp and wide door for getting that in and out, and a parking area for the truck that brings it. Also consider storage: you will need a place store the instrument cases, road cases, unused gear, unused instruments, etc. during the session, and between sessions.

If you think there's a real possibility that you'll need a live room in the future, then it should go in the plans NOW, even if you don't build it yet. It's really hard to add on parts of a studio where no provision was ever made for that initially. Even simple things, such as not routing wiring, cables or ducts through certain parts of the studio because that area might become a window or door in the future, are things that will make your life a LOT easier if you ever do add on that LR later.

Quote:
Regarding room shapes and RFZ designs. I won't re-quote everything you wrote. Suffice to say that you answered all my questions really well and pretty much sold me on a RFZ design.
:thu:

Quote:
I'm using Event Opals at the moment which would be a bit tricky to soffit mount given their slightly ovular shape. I'm also considering Focal SM9's as a future addition and these can't be soffit mounted either.
The Opals are not a problem. They could be soffit-mounted without too much hassle. Cutting the baffle to follow that shape is not a big deal: any decent carpenter worth his salt should be able to do that. The SM9's, on on the other hand, are a big deal! Those cannot be soffit mounted, unfortunately. That's about the only speaker type that cannot be soffit mounted at all. Pretty much everything else can.

If you are in the market for new speakers right now, then do yourself a favor and take a look at the offerings from Eve Audio. They are pretty darn good. I already gave you a link to the Studio Three build thread ( www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=20471 ) and those results were achieved with a pair of Eve SC-407's, soffit mounted vertically. The speakers that were install originally were pretty good (Genelec's), but were old, and one of them started making strange noises, so the owner decided to replace them and upgrade to something better suited to that room. We looked around, but there were manufacturing and shipping delays with my first choice of a replacement, and that's when I came across Eve Audio. I liked the specs for the SC-407s, but they were not designed to be soffit mounted, and are meant to be used horizontally, so I contacted them, and the chief engineer was very helpful: He agreed with me that vertical mounting would be a better option for that room, and that the speakers would perform just fine like that: there's an option for rotating the center driver section in those speakers to do exactly that. He also gave me his blessing on soffit-mounting them, and gave me some tips on how to do it. So the owner at Studio Three got a pair of those, and we soffit mounted those... with the results that you can see in that thread! I had originally designed the soffits with a "pull-out" module, to make it easy to replace the speakers, and it just took a few hours to actually swap them, then some room tuning to optimize the response... and you can see the results. I was pleasantly surprised by how well those Eve's perform in that space, and since it seem like your room will be a similar size to Studio Three, I'd recommend that you take a look at those in your search for new speakers.

Quote:
Thanks again for all your help so far. I'm moving in to the new place in 4 weeks and I'm super keen to get things started.
Cool! Please do keep us posted on the design progress! I'm really looking forward to seeing how this moves forward!


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PostPosted: Tue Feb 28, 2017 5:24 pm 
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Location: Apollo Bay, Australia
Just checking in with a progress update and a couple of new questions.

I moved in to my new place 2 weeks ago. I've selected a location for the studio and have assessed the soundproofing requirements. This has been a fun, sciency process that brought back memories of my uni days when I studied biology. Lots of field work back then.

This is the proposed site. It's a clearing of about 1,500 square metres that's almost flat and bordered by trees.
Attachment:
Studio Location.jpg


At this stage the plan is still for a combined composing/mixing room, a good sized vocal booth, storage and a loo.

Traffic and other mechanical noises are virtually non-existent here. The biggest sources of noise are:

1. Wind in the trees. This is an elevated position that often receives strong sea breezes.
2. Intermittent mooing. The site is next to a 145 acre property that is sometimes used for grazing cattle. The cows aren't always around, but on some days there is quite a bit of mooing going on.

Attachment:
Cows.jpg


The cows are hidden behind the trees. When they come right up to the fence they are at least 25 metres from the proposed studio, but they can still be quite loud at that distance. Using a sound level meter the loudest cow I recorded (c weighted, fast) was 82 decibels at 12 metres. There are some really boisterous tenors among the herd. If memory serves, this 82db would drop to 76db at 24 metres. If they become too bothersome I can chase them away pretty easily. They are a pack of wusses and don't seem to like me approaching them. Perhaps a couple of big McDonalds logos placed along the fenceline will help to keep them well back.

Much of the time the ambient environmental noise is just 45 - 55 db. But I tested the wind noise on a very windy day and the highest level was 75db (c weighted, slow). This surprised me. It seems louder than that because of the wide frequency spectrum and the fact that the sound is coming at you from all directions, but then you realize that you can still have a conversation with someone one metre away without really raising your voice.

I also recorded the wind (from a protected position with blimp windshields) and generated an eq curve for the noise profile. I then calibrated the peak of the curve to the peak level I tested with the level meter. This resulted in the graph below. Is this the correct way to assess noise levels across the frequency spectrum?

Attachment:
Noise Profile Apollo Bay.jpg


If I understand this correctly I can compare the chart above to the NC chart below to assess my soundproofing requirements at various frequencies.

Attachment:
noise criteria curves.png


It's interesting to note that without any man made noises, the curve of the noise profile follows the NC curves pretty closely. If I've done this right (please tell me if I've stuffed this up) then to get NC15 I need:

23 db of noise reduction at 63 Hz (70db actual - 47db required)
29 db of noise reduction at 250 Hz (58db actual - 29db required)
32 db of noise reduction at 500 Hz (55db actual - 23db required)
30 db of noise reduction at 2,000 Hz (45db actual - 15db required)
etc

If I also take into account the loudest cow which will peak at around 75 db at 125 Hz then I'd need 39 db of noise reduction at that frequency. Cows often produce lower frequencies than 125 Hz due to their large chest cavity, but I've discovered that cows have a pretty steep LF roll off below 90 Hz. I'm becoming quite the expert in moo harmonics.

These noise reduction requirements seem lower than I was expecting. I think that a single leaf concrete block wall would probably satisfy them. But if I (a) take into account the possibility of big wind gusts / rain and (b) aim to get a few dB under the NC15 line, then I'm inclined to add another 10dB to these requirements. Perhaps 15db for the vocal booth where quiet becomes even more critical. Does this seem like good sense to you? I am inclined to build some extra capability into the structure rather than just achieve the bare minimum.

Finally, I've been wondering about the possible effects of wind on the structure itself. Specifically, might strong winds cause the structure to creak? Could wind cause turbulence around the structure that might produce additional LF noise that I haven't seen in my tests. I'm wondering if concrete block might be the best structural material for the external shell of this building (to provide mass and rigidity) but this is not my area of expertise.

Thanks again for all your help. Once I've confirmed my noise reduction requirements I can figure out what materials and methods will achieve them.

Cheers!
Chris


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PostPosted: Wed Mar 01, 2017 2:32 am 
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Thanks for making me laugh out loud! Moo harmonics.. I've not seen before such detailed analysis of the noise outside of a studio generated by nature. Good work.

Oh, and what an awesome location for your studio. I am highly envious!

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PostPosted: Wed Mar 29, 2017 1:08 pm 
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Quote:
Using a sound level meter the loudest cow I recorded (c weighted, fast) was 82 decibels at 12 metres.
Wow! I didn't realize cows would be that loud. Interesting! A new fun-fact to note down in my book of "strange but true acoustical things".

Quote:
Perhaps a couple of big McDonalds logos placed along the fenceline will help to keep them well back.
I like the way you think! :)


Quote:
Much of the time the ambient environmental noise is just 45 - 55 db.
What about thunder? Rain? Hail? Aircraft? Helicopters? Farm machinery?

Quote:
If I understand this correctly I can compare the chart above to the NC chart below to assess my soundproofing requirements at various frequencies.
Not really. That's isn't the purpose of the NC (or NR) curves. That describes the desired noise floor in your room, NOT the amount if isolation you need. That's more about HVAC than it is about cows. It's how silent you want it to be inside your room, with the HVAC on and all your gear running. Studio gear often has fans and hard disks in it, and if you have a tape deck then you have motors and solenoids too. Your NC curve is what you want the room to be like with all of that running. NC-20 is a reasonable level to shoot for. NC-15 is even better. But certainly nothing over NC-25.

Quote:
It's interesting to note that without any man made noises, the curve of the noise profile follows the NC curves pretty closely. If I've done this right (please tell me if I've stuffed this up)
Have you taken into account the Fletcher-Munson curves? :)

Quote:
These noise reduction requirements seem lower than I was expecting.
Right! Because you are using the wrong tool for the wrong job. Or maybe the right tool for the wrong job. Or is it the wrong tool for the right job? Now I'm confusing myself! :)

NC curves are not what you need to decide in isolation, as I mentioned above. Consider this: by using NC curves, you came to the conclusion that you need around 30 dB isolation to kill your cows (figuratively!). Your cows are around 82 dB, so if you had 30 dB of isolation, you'd have coes in your room at 42 dB. Still very audible, if the noise floor in your room is NC-15. If you wanted your 82 dB cows to be absolutely inaudible inside a room with an NC-15 noise floor, then you'd need isolation of around 67 dB. That's a pretty tall order, and since you don't really need totally silent cows, a more realistic isolation figure would be around 55 dB. That is doable, and reasonable. Your 82 dB cows will be coming in at around 27 dB like that, and since most people consider 30 dBC to be "silent", by most subjective measures, your cows will be silent like that. Or you could just set up a BBQ, and silence them in a tastier fashion....

In the other direction, let's say that you one day you decide to track acoustic drums. A drum kit can put out around 115 dBC without too much trouble (and 120 played hard by a gorilla). So assuming you have 55 dB isolation, 115-55=60 dB outside the wall. Allowing for inverse square and air attenuation, etc, at a distance of 60m or so, that too will be down to "silent".

Quote:
I think that a single leaf concrete block wall would probably satisfy them.
A single-leaf concrete wall can, indeed, get you 60 dB of isolation... provided that you make it 75 cm thick! Roughly 30 inches). For a single-leaf wall, the equation known as "mass law" applies. It goes like this:

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

W is the surface density of the panel, and
f is the frequency

That's if you wanted to calculate for each frequency, and draw a graph, but if you want a real.world empirical estimate, then there's a briefer version:

TL = 14.5 log (Ms * 0.205) + 23 dB

Where: Ms = Surface density in kg/m2

The absolute density of concrete is around 2400 kg/m3, so a wall 75cm thick = 2400*.75=1800 kg/m2. Plug that into the equation:

TL = 14.5 log (1800 * 0.205) + 23 dB
TL = 14.5 log (369) + 23 dB
TL = 14.5 (2.567) + 23 dB
TL = 60.22 dB

So if you wanted to do a single-leaf concrete wall that will get you 60 dB of isolation, the answer is "75 cm thick". The same applies to your ceiling, of course. And to your windows, doors, HVAC system, and electrical system. On the other hand, you can get the same isolation (and better) from much thinner (=less expensive) walls, using two.leaf walls, ceilings, windows and doors.

Quote:
But if I (a) take into account the possibility of big wind gusts / rain and (b) aim to get a few dB under the NC15 line, then I'm inclined to add another 10dB to these requirements. Perhaps 15db for the vocal booth where quiet becomes even more critical.
Wrong tool. Wrong job. Wrong answer! :)

Quote:
Does this seem like good sense to you? I am inclined to build some extra capability into the structure rather than just achieve the bare minimum.
That's the interesting thing about Mass Law. It tells you what you need to do to increase your isolation. It tells you that if you double the mass of your wall, you will get an increase of 6 dB. To double the mass of a concrete wall, you obviously only need to make it twice as thick. So if you wanted to go from 60 dB isolation to 75 dB isolation, you would need to double your wall thickness from 75cm to 150 cm, and that would increase you from 60 to 66, then double it again (from 150 cm to 300 cm) to get you to 72 dB... I think you see where this is going... nowhere interesting!

On the other hand, doubling the mass of a two.leaf wall gets you an increase of anywhere between 12 dB and 18 dB, depending on the frequency....

Quote:
Finally, I've been wondering about the possible effects of wind on the structure itself. Specifically, might strong winds cause the structure to creak?
Not concrete, no. And especially not concrete that is 3 meters thick... :)

Quote:
Could wind cause turbulence around the structure that might produce additional LF noise that I haven't seen in my tests.
No, but the noise itself might get in, if you happen to experience the cyclone that is wiping out Queensland right now.

Quote:
I'm wondering if concrete block might be the best structural material for the external shell of this building (to provide mass and rigidity) but this is not my area of expertise.
Concrete block is a good choice for your outer leaf, but not by itself. It needs structural columns every couple of meters along the length of each wall, to provide rigidity, strength, load-bearing capacity, etc. Your structural engineer will tell you how many of those you need, how close they need to be, and what the dimensions would need to be.

Quote:
Thanks again for all your help. Once I've confirmed my noise reduction requirements I can figure out what materials and methods will achieve them.
I would suggest something between 50 and 60 dB as a reasonable goal for your isolation needs. You can go higher, but that' gets very expensive, very fast, and you don't need it (the cows probably don't care about distant drums anyway). But I would not go lower than about 50.



Quote:
Thanks for making me laugh out loud! Moo harmonics.. I've not seen before such detailed analysis of the noise outside of a studio generated by nature. Good work.
Agreed! And in honor of that, I'd like to propose a new unit for acoustic noise measurement of farm noise: I suggest the "Moooonit" should be the amount of transmission loss needed to completely silence one cow at a distance of 10m. So a 2 mooonit wall would be good for two cows at 10m, a 3o mooonit wall would work for thirty cows, etc. It seems like a very valuable and useful unit, that everybody would need! :) 8)
:shot:


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PostPosted: Wed Mar 29, 2017 7:23 pm 
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Location: Apollo Bay, Australia
Soundman2020 wrote:
Wow! I didn't realize cows would be that loud. Interesting! A new fun-fact to note down in my book of "strange but true acoustical things".

I was surprised too. Just think of a four legged Pavarotti with giant udders. They can really pump out some volume. In fact, the "moo" sound we can all imagine actually breaks up into a death metal type of screech when they really belt it out.

So, an 82 decibel moo at 12 meters. From memory I deduct 6db for every doubling of distance, so I would have 76db of cow noise reaching the studio location (I was 12 metres from the cow during measurement, but it turns out that the studio will be 25 metres from the nearest possible cow (NPC).

Soundman2020 wrote:
What about thunder? Rain? Hail? Aircraft? Helicopters? Farm machinery?

I suppose weather is something that all freestanding studios must encounter from time to time hey? The wind and cows I measured were the two most significant sources of noise in a month. I'm sure that some 120+ db thunder claps will happen at some stage though! Some noises are just about unbeatable. :shock:
Aircraft and machinery? There has been one helicopter in an entire month. That's it. There are some offroad vehicles around but they are far away.

Most of the time it is really quiet here, except for wind and high frequency sounds like birds and crickets. When I close the windows it is often "studio quiet" inside my house.

It's a tricky thing - deciding what intermittent noises to take into account when soundproofing. Our neighbours have recently moved their cows so I've heard nothing of them for over a week. But I know that they could come back so I have to take them into account. Those bovine tenors are gonna cost me.

Soundman2020 wrote:
Not really. That's isn't the purpose of the NC (or NR) curves. That describes the desired noise floor in your room, NOT the amount if isolation you need. That's more about HVAC than it is about cows. It's how silent you want it to be inside your room, with the HVAC on and all your gear running. Studio gear often has fans and hard disks in it, and if you have a tape deck then you have motors and solenoids too. Your NC curve is what you want the room to be like with all of that running. NC-20 is a reasonable level to shoot for. NC-15 is even better. But certainly nothing over NC-25.

Got it. So NC15 is a measure of permissible noise inside a studio that is produced by studio equipment itself. It's not a measure of permissible noise levels from exterior sources.

Soundman2020 wrote:
Your cows are around 82 dB, so if you had 30 dB of isolation, you'd have coes in your room at 42 dB. Still very audible, if the noise floor in your room is NC-15. If you wanted your 82 dB cows to be absolutely inaudible inside a room with an NC-15 noise floor, then you'd need isolation of around 67 dB. That's a pretty tall order, and since you don't really need totally silent cows, a more realistic isolation figure would be around 55 dB. That is doable, and reasonable. Your 82 dB cows will be coming in at around 27 dB like that, and since most people consider 30 dBC to be "silent", by most subjective measures, your cows will be silent like that. Or you could just set up a BBQ, and silence them in a tastier fashion....

Makes sense. Due to their distance from the studio, the cows would peak at 76db, so to get them down to say, 26 db would require 51db of noise reduction...roughly what you recommend at the end of your last post.

Soundman2020 wrote:
A single-leaf concrete wall can, indeed, get you 60 dB of isolation... provided that you make it 75 cm thick! Roughly 30 inches). For a single-leaf wall, the equation known as "mass law" applies. It goes like this:

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

W is the surface density of the panel, and
f is the frequency

That's if you wanted to calculate for each frequency, and draw a graph, but if you want a real.world empirical estimate, then there's a briefer version:

TL = 14.5 log (Ms * 0.205) + 23 dB

Where: Ms = Surface density in kg/m2

The absolute density of concrete is around 2400 kg/m3, so a wall 75cm thick = 2400*.75=1800 kg/m2. Plug that into the equation:

TL = 14.5 log (1800 * 0.205) + 23 dB
TL = 14.5 log (369) + 23 dB
TL = 14.5 (2.567) + 23 dB
TL = 60.22 dB

So if you wanted to do a single-leaf concrete wall that will get you 60 dB of isolation, the answer is "75 cm thick". The same applies to your ceiling, of course. And to your windows, doors, HVAC system, and electrical system. On the other hand, you can get the same isolation (and better) from much thinner (=less expensive) walls, using two.leaf walls, ceilings, windows and doors.

May I just say, "I love maths and physics". This is bedtime reading for me.

The only reason I was suggesting a single leaf concrete wall was because I underestimated my soundproofing requirements. With 50db+ to aim for a two leaf system makes much more sense. I'll still probably use concrete for the outer leaf for mass and stability. The inner leaf will probably be a good ol' fashion timber frame with a layer of ply and a layer or plasterboard. Nothing too groundbreaking there.

Soundman2020 wrote:
Have you taken into account the Fletcher-Munson curves?

Yep. After my bedtime reading I lay awake contemplating the correlation between the F-M curve and the evolution of human hearing.

No I am not joking. I need some other hobbies.

Soundman2020 wrote:
Agreed! And in honor of that, I'd like to propose a new unit for acoustic noise measurement of farm noise: I suggest the "Moooonit" should be the amount of transmission loss needed to completely silence one cow at a distance of 10m. So a 2 mooonit wall would be good for two cows at 10m, a 3o mooonit wall would work for thirty cows, etc. It seems like a very valuable and useful unit, that everybody would need! :) 8)
:shot:

I've been out-dorked. Great work.


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PostPosted: Wed Mar 29, 2017 11:53 pm 
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Quote:
So, an 82 decibel moo at 12 meters. From memory I deduct 6db for every doubling of distance, so I would have 76db of cow noise reaching the studio location (I was 12 metres from the cow during measurement, but it turns out that the studio will be 25 metres from the nearest possible cow (NPC).
True, but you are assuming your pets will behave well, and only ever moo one at a time... If you have two of them mooing together, that's a 3 dB increase in SPL, but double the sound power. Half a dozen letting out a real "deep sigh of bovine satisfaction", all together could be quite something! :shock:

But anyway, from all you say it seems like a goal of 50 to 60 dB isolation is probably about right for you.

Quote:
I'll still probably use concrete for the outer leaf for mass and stability. The inner leaf will probably be a good ol' fashion timber frame with a layer of ply and a layer or plasterboard. Nothing too groundbreaking there.
sounds like a good plan to me! Don't forget the insulation in the cavity between the leaves.

So it seems like it's time to start putting your ideas into SketchUp, and forming the basic design!

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PostPosted: Fri Aug 04, 2017 9:52 am 
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Location: Apollo Bay, Australia
Progress update and a quick question about windows...

It's been a while but this project is still moving forward and I've been working with an architect on the studio plans for the last couple of months.

My original budget looks like a tiny little speck on the horizon now. Apollo Bay is three hours south west of Melbourne, which is currently the 6th most expensive place in the world to purchase real estate. Building this far out of town just makes things even more expensive due to the extra transport costs. I console myself with the idea that this is a "once in a lifetime" opportunity and that this is the place in which I may spend the rest of my music making days.

I can confirm a few basic details. The building will have an entry airlock / foyer that wraps around two sides of the studio. This creates an acoustic buffer between the outside world and the entry doors to the studio, while also providing storage space, access to a toilet and a bit of room to relax and take in the views to the east and north. The studio itself will be one room that is for composing and mixing 99% of the time, with occasional vocal recording taking place. This room will have interior dimensions of 5.5m wide x 7.5m long x 3.2m high (perhaps slightly longer than that if the budget will allow it).

I have one question about windows today. The studio will be built with a 150mm thick concrete outer wall and a fully decoupled inner leaf of plywood and 16mm Fyrcheck plasterboard. There will be a couple of windows to take in the views to the south and the north. One of them is quite large, being around 3m wide and 1m tall. These will have 19mm thick glass on the outside and 12mm on the inside.

In Rod Gervais' book he writes, "...it has been proven (through lab testing) that a heavy wooden window frame that runs continuously through the opening does not essentially weaken the TL value of a wall; however, if you absolutely want the "maximum benefit" your best bet is to use a separated wood frame assembly".

I guess I'm just looking for second opinions on this. Using a single frame is simpler and would probably be more cost effective (which would be great), but I wonder how much isolation I'd be sacrificing by not using two separated frames. It seems to me that a single frame would create a physical coupling between the two leaves, and yet "lab testing proves" that this won't be a problem? If we're just talking about a couple of db difference between the two methods then I'll choose the simpler path.

Hmmm. I'd love to know what you think about this.

Just for fun here are a couple of location shots. The views are really nice so you can see why window are important. The large window I just mentioned faces west so it lets in the most fantastic light in the evening. Sunsets over the surrounding hills are beautiful.

Attachment:
South-View.jpg


Attachment:
West-View.jpg


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PostPosted: Sun Aug 06, 2017 2:27 am 
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Quote:
My original budget looks like a tiny little speck on the horizon now.
Welcome to the wonderful world of home studio design/construction! That's the first rule: it will always cost MUCH more than you ever imagined... :)

Quote:
The building will have an entry airlock / foyer that wraps around two sides of the studio. This creates an acoustic buffer between the outside world and the entry doors to the studio,
Not if it only isolates on two sides it doesn't! :) You'll also need similar separation of the leaves on the other two sides, and the ceiling.

Plus, I'd need to see the details of how that "wrap-around airlock" is actually going to be built. Are you CERTAIN that you are dealing with the various leaves correctly, to prevent flanking? Are you certain that you are not creating a 3-leaf or 4-leaf system? Are you CERTAIN that you are not trying to create a "room" inside the MSM cavity? those are common mistakes...

Quote:
The studio will be built with a 150mm thick concrete outer wall and a fully decoupled inner leaf of plywood and 16mm Fyrcheck plasterboard.
That's fine, but I think you'll find that OSB is less expensive than plywood, and just as good (or better) for structural strength, which is one of the main reasons why you need it.

But you only described the walls: what about the ceiling/roof?

Quote:
These will have 19mm thick glass on the outside and 12mm on the inside.
That sounds rather strange, for 150mm concrete block and plywood+drywall. Did you do the math here? Are you aware of the "continuity of surface density" rule when selecting glass thickness? That rule (or maybe "guideline" is better) says that the surface density of each leaf must remain roughly the same at all points, consistent throughout. The point being that the place on each leaf that has the lowest density is the weakest link in your entire isolation system. If there is one area where the surface density is considerably lower than the rest of the leaf, that places a limit n the isolation of the entire building. So the surface density of the glass on your outer.leaf needs to be high enough that the isolation at that point will still be higher than the overall target isolation. Did you do the math there? Are you certain that " 19mm thick glass on the outside and 12mm on the inside" is going to get the MSM resonant frequency down low enough? And that the combination of mass on those two panes combined with the size of the air gap (which must, of necessity, be undamped), will provide the minimum isolation that you will need for the entire building?


Quote:
It seems to me that a single frame would create a physical coupling between the two leaves,
I agree. Which is why I always do separate frames on all of the studios I design.

Quote:
and yet "lab testing proves" that this won't be a problem?
I have heard the claim, but never seen the proof. Presumably the lab test in question is out there somewhere, but I have not seen it. From what I know, and from experience, bridging the inner-leaf to the outer-leaf with a solid, rigid, massive link will create copious flanking between the two, transmitting sound from one side to the other.

Do you happen to have an old-fashioned tuning fork? If so, you can demonstrate to yourself just how much sound can be transmitted between leaves through a single nail. Tap the tuning fork on something hard and hold it up in the air. That's how loud the vibration can be in a nail by itself, that extends par way across the wall cavity but does not touch the other side. Now tap the tuning fork again, but this time instead of holding it up in the air, put the base of the fork down on the table in front of you. That's how much sound a single nail can transmit when it DOES touch the leaf on the other side.

I think that answers your question! :)


Here's a series of images from the way one of my customers in Australia did his windows that might interest you, since he did it "together yet separate":

First, one of the frames being prepared:

Attachment:
BRAUS-window-01--main-outer-frame.jpg




Now both of the frames (inner-leaf and outer-leaf). You can see how they are held together temporarily with bracing blocks that will later be removed, and you can also see the black fabric firmly glued and taped in place across the gap between the frames:

Attachment:
BRAUS-window-02--both-outer-frames-cloth-and-tape.jpg



Here you have the "single-unit of both frames" being put into position within the rough framing of both walls. One frame ends up resting on ONLY the outer leaf, and the other on ONLY the inner leaf.

Attachment:
BRAUS-window-03--both-outer-frames-in-place.jpg





Now the temporary blocking is removed (after the frames have been attached to the rough framing, of course!), and the frames are sanded and varnished, and the inner blocking is prepared to receive the glass, with glazing tape:

Attachment:
BRAUS-window-04--inner-frames-with-glazing-tape.jpg


So at this point, the two frames are completely separate, even though they were joined together for the purpose of installing them simply.




Now pane of thick laminated glass for the inner-leaf goes in place:

Attachment:
BRAUS-window-05--first-glass-ready.jpg


Attachment:
BRAUS-window-06--first-glass-going-in-2.jpg


In the above, the glass is held in place while the outer seals and blocking are put in place.



Here's a view from inside the window cavity, , between the two frames, showing just the inner glass in place with the second seal completed:

Attachment:
BRAUS-window-07--one-pane-in--middle-view.jpg



Then the second pane goes into the outer-leaf frame, from the outside:

Attachment:
BRAUS-window-08--second-pane-going-in.jpg



The finished view form the outside, completely sealed in place with the final trim done:

Attachment:
BRAUS-window-10--finished-outside-2.jpg



And the view from the inside, window completely finished:

Attachment:
BRAUS-window-11--finished-window-from-inside-4.jpg



So that's an easy way to do it. The key here is that both frames are held "together-but-apart" with temporary blocking, so they can be handled as a single unit while they are being installed, then the blocking is removed once they are firmly in place and sealed.

In this case, the customer is getting over 60 dB of isolation, which is far better than the majority of home studios. He needs it, because he teaches drums! So he has TWO drum kits going full blast at times... and his neighbors are just a couple of meters away.


Of course, all of the above assumes that the entire building has been designed correctly for high isolation by a studio designer (not an architect! :) ), taking all the precautions that studio designers know about (but architects don't ... :) ).

It's not just the windows that matter: it's the entire isolation system, which involves the inner leaf walls, outer leaf walls, inner leaf windows, outer leaf windows, inner leaf doors, outer leaf doors, the liner-leaf ceiling, the outer-leaf ceiling, the entire HVAC system from end-to-end (including the inner-leaf silencer boxes and the outer leaf silencer boxes on both the supply ducts and the exhaust ducts, as well as the actual split system), and the entire electrical system (including all of the usual defenses that studio designers commonly use, but electricians and architects aren't even aware of), plus the actual shape and size of the room(s), and the internal acoustic treatment. It all works together as a single system. And getting even one part of it wrong can be just as bad as allowing a single nail (tuning fork) to touch the other side...

Quote:
Just for fun here are a couple of location shots. The views are really nice so you can see why window are important. The large window I just mentioned faces west so it lets in the most fantastic light in the evening. Sunsets over the surrounding hills are beautiful.
If you ever get tired of making music, then you clearly have an excellent fall-back career as a photographer! Those are really stunning photos.


- Stuart -


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PostPosted: Sun Aug 06, 2017 11:08 am 
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Location: Apollo Bay, Australia
Soundman2020 wrote:
Not if it only isolates on two sides it doesn't! :) You'll also need similar separation of the leaves on the other two sides, and the ceiling.

Plus, I'd need to see the details of how that "wrap-around airlock" is actually going to be built. Are you CERTAIN that you are dealing with the various leaves correctly, to prevent flanking? Are you certain that you are not creating a 3-leaf or 4-leaf system? Are you CERTAIN that you are not trying to create a "room" inside the MSM cavity? those are common mistakes...

I can see how my description could be misleading. Here's a very rough floorplan sketch that I created to clarify (not to scale - just a quick sketch). Can't post the actual plans yet as they are still evolving, but this gives you the general idea. The thick grey lines are the concrete walls. The darker inner line is the decoupled inner wall made from a sandwich of ply (or OSB) and plaster. Blue lines are windows.
Attachment:
Studio-Floorplan-Basic-Mockup.jpg

The walkway that wraps around the outside of the studio is between 1.5m and 2.5m wide, so it's not really acting as a third leaf. It's just a part of the overall building.

It was anticipated that the doors to the studio would be one of the biggest weak points from a soundproofing perspective, so we located them inside this walkway so that there is already some noise attenuation from the outside world before you even get to the studio doors.

Soundman2020 wrote:
But you only described the walls: what about the ceiling/roof?

The ceiling will be the same as the walls. 150mm concrete bondek roof on the outside, plywood and plaster on the inner leaf - all fully decoupled. As you might expect, the whole building will be on a concrete slab.

Soundman2020 wrote:
That sounds rather strange, for 150mm concrete block and plywood+drywall. Did you do the math here? Are you aware of the "continuity of surface density" rule when selecting glass thickness? That rule (or maybe "guideline" is better) says that the surface density of each leaf must remain roughly the same at all points, consistent throughout. The point being that the place on each leaf that has the lowest density is the weakest link in your entire isolation system. If there is one area where the surface density is considerably lower than the rest of the leaf, that places a limit n the isolation of the entire building. So the surface density of the glass on your outer.leaf needs to be high enough that the isolation at that point will still be higher than the overall target isolation. Did you do the math there? Are you certain that " 19mm thick glass on the outside and 12mm on the inside" is going to get the MSM resonant frequency down low enough? And that the combination of mass on those two panes combined with the size of the air gap (which must, of necessity, be undamped), will provide the minimum isolation that you will need for the entire building?

I am aware that the surface density of each leaf needs to be consistent. I've tried to match the densities the best I could without going completely overboard. Obviously I am not going to be able to match the density of the outer leaf (150mm thick concrete) without spending a fortune on similarly thick glass.

The inner leaf was easier to match. 12mm thick should already exceed the mass of the plywood+plaster leaf so I figured there's no point going any thicker on that leaf. The gap between panes will be about 240mm.

Perhaps I'm not going overboard enough! Obviously 19mm glass provides much less mass than 150mm concrete. Am I weakening the isolation of the structure excessively with 19mm glass on the outside? I could go thicker but costs escalate pretty quickly with thick glass.

Confession - I did not do the math on MSM resonant frequencies (could use some guidance there). I did the math on matching the mass of windows to the mass of the walls, realized I couldn't match the outer leaf and then took an "educated guess :oops: " as to what would provide good amount of isolation. I could find very little in the way of TL figures for thick glass (despite hours of searching) but concluded that the mass of 19mm glass would be equivalent to 4 layers of 16mm fyrcheck plaster. I'm aiming for a minimum attenuation of 55db of outside noise and I've gotta draw the line somewhere. Do you think I've gone far enough?

Side note: we decided to use pre fab concrete for the outer walls after taking a number of factors into account. There are cheaper materials we could have built with, but would require much more labour in construction. The concrete shell of the studio can be installed in a day.
*

Thank you SO MUCH for that fantastic sequence of photos of window construction and for confirming my suspicions. I'll definitely use separated frames. It seemed nuts to me that anyone would go to the trouble of decoupling two walls and then bolt them together with a window frame.

Soundman2020 wrote:
Of course, all of the above assumes that the entire building has been designed correctly for high isolation by a studio designer (not an architect! :) ), taking all the precautions that studio designers know about (but architects don't ... :) ).

It's not just the windows that matter: it's the entire isolation system, which involves the inner leaf walls, outer leaf walls, inner leaf windows, outer leaf windows, inner leaf doors, outer leaf doors, the liner-leaf ceiling, the outer-leaf ceiling, the entire HVAC system from end-to-end (including the inner-leaf silencer boxes and the outer leaf silencer boxes on both the supply ducts and the exhaust ducts, as well as the actual split system), and the entire electrical system (including all of the usual defenses that studio designers commonly use, but electricians and architects aren't even aware of), plus the actual shape and size of the room(s), and the internal acoustic treatment. It all works together as a single system. And getting even one part of it wrong can be just as bad as allowing a single nail (tuning fork) to touch the other side...

I consider myself thoroughly forewarned. Having said that, I've read enough of your posts over the last 3 years to be completely unsurprised by your words of caution!

We are taking into account every aspect you just mentioned. I can't even tell you how much this forum has helped. I do have a lot of faith in my chosen architect. He is also an experienced musician and has spent time in a number of studios and is doing a PhD in a subject that combines architectural design and music. So while not a professional studio designer, he has a great understanding of the special needs of recording studios. Almost all of the quirky elements of studio design I've thrown at him so far have been totally familiar to him. He knows his limits though and has suggested the services of an acoustician who we may contract to check the overall plan as it comes together. Feel like I'm in good hands at the moment, especially with the added benefit of your advice Stuart.

Thank you again for the excellent pictures.


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PostPosted: Wed Aug 16, 2017 3:45 pm 
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Location: Apollo Bay, Australia
Okeydokey. Tracked down the calculations for double leaf MSM.

Fc=c[(m1+m2)/(m1m2d)]^.5

where:

Fc=resonance frequency (Hz)
c=constant (60 for empty gaps and 43 for with insulation)
m1=mass of first leaf (kg/m^2)
m2 mass of second leaf (kg/m^2)
d=interleaf spacing (m)

Calculated Fc for my walls to be 26 Hz, and for my windows, 29 Hz.
The outer glass has less mass than the concrete outer wall, but the air gap in the windows is much larger than the air gap in the walls so this helped to compensate.

Increasing the thickness of the outer glass to 25mm would lower the Fc of the windows to 27 Hz. Increasing to 32mm would lower the Fc to 26 Hz. Groovy. :D


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PostPosted: Wed Aug 16, 2017 5:18 pm 
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Congratulations Chris, the location is beautiful!


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PostPosted: Mon Apr 23, 2018 5:22 pm 
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Posts: 74
Location: Apollo Bay, Australia
I can't believe it's been 9 months since I last posted about this studio.

I'm just stopping by to say that progress has been made. I have council approval to build and we are finalizing the detailed architectural plans now.

For informative purposes, here's some of the services you'll pay for in order to design and get permission to build in Australia (and many other countries presumably).

Land surveyor (to map the layout of the site).
Geotechnical survey (to test the soil).
Architect / design fees (at around 10% the value of the building).
Engineers fees (to ensure that the right structural materials are used in the building).
Council planning permission fees.

In rural areas you may also have to pay for a bushfire attack level assessment, and also a a land capability assessment.

I said it before and I'll say it again...building in Australia is not cheap, especially around Melbourne or Sydney. For anyone thinking about building a studio, expect to pay $3,000 AUD to $4,000 AUD per square metre for a good quality building. The only ways I can think of to do it cheaper than this is to self build (which you can only do if you're a licensed builder) or perhaps put up a tin shed and fitout the inside.

There have been lots of little changes to the design of this studio over time. I'll share some details in a follow up post later on. The soundproofing requirements have been revised too. There have been no cows around for over 6 months. The only noise here is wind and rain. There is no traffic. I hear a plane off in the distance once a month or so. Seriously, it is super quiet most of the time but occasionally the wind gets a bit extreme.

Anyway, after more than a year I have nothing to show but a bare block of land. Ah, but what a block...
Attachment:
garden.jpg

Looking forward to sharing something more tangible than plans and dreams sometime soon.

Cheers!


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