First time attempt at timber build studio....need help!!!!!

hi, im about to embark on building my own studio at the top of my very steep garden. (a step up from the spae room in my house!) Its going to have to be timber frame due to the logistics of block work in a conservation area and the steepness of the garden. The nearsest house is 30 metres away, so hopefully sound proofing wont be to much of an issue, however id like to do my best for the neighbours!! Dimensions wise the area i have is 16Ft by 12Ft, i have constructed a concrete perimeter about a metre wide, again making a whole concrete slab would have been tricky due to location. Not recording any drums, but would like to record my electric and some acoustic, again without hopefully disturbing to many people. The rest is synths and computer based. My thoughts are to create two rooms, a control room and a small live room for the guitar work, maybe some vocals. But unsure if i have the space for two rooms or should stick with one Ive read many posts, but being first time build for me would appreciate any advice, as most studios posted here are usually block built for obvious sound isolation reasons, this is not a choice for me, so curious on suggestions on a timber frame built from scratch, also advice on floor as no concrete base here, just a perimeter, appreciate any advice given! The base is done, so now the tricky part!! Have read so many different posts on decoupling etc have myself confused on what would be best, like i say nearest house is 30metres away. thanks for any advice in advance rich

Hi Rich and welcome. After reading about your situation a previous project studio, posted here came to mind. http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=10847&p=77853&hilit=GARDEN+SHED#p77853 Its actually a shed conversion but many of the items discussed within the project are relevant to your plan. Given the size of your space, have you considered having a control room and a small iso room for an amp to go in. Then doing any vocals with a reflexion filter, like the one below, in the control room with headphones? Mite give you some more room to play with in the control room. http://www.studiospares.com/mic-accessories/studiospares-red50-mic-filter/invt/465210/ hope this helps :D

Hi thanks for the advice, have been doing quite a bit of reading, though find myself more and more confused!! Never realised how complex sound waves could be! Anyway so heres my thoughts, as am getting quite near to construction! :) Im thinking 12mm exterior ply sheets to make the external walls, though 18mm if can afford but not sure if will make that much difference? Then either 50mm polystyrene insulation (am told this is great for heat but useless for sound proofing!) then 50mm rockwool, or would i be better just going for 100mm rockwool, again this is confusing between various websites, especially the us/uk terminology! And Then two layers of plasteboard of different thinkness seperated by green glue? Again is plasterboard called sheetrock in the US? The floor im still unsure about, still pondering whether to fill my concrete perimeter with sand and pound it down level, will this help on the base? Also worried about moisure\condensation and have no clues about ventilation!! Please feel free to tell me if im way off the mark, as it is my first attempt at such a project, im looking forward to having all my musical gear in one place instead of spread over the house! Like i said in my previous post, nearest neighbours are at least 50 metres away, but know how sound travels, so still pondering a seperate isolation room inside the main build to house my Mesa Boogie 2:90 rig! Would love to be able to play this without bothering the neighbours, but it is loud when wound up! Still find the room within a room confusing! especially when dealing purely in timber. I want to get it as right as i can afford from the start, doors im now going to make, have read some great tips picked up on various posts for this, and probably will eventually clad the outside of the shed with something more decoritive, also thinking that another layer for that sound wave to travel through! Alot of people post what they have done but never whether it was effective! A friend of mine who built his studio years back said he lined the walls and roof with rooging felt?? Thats a new one, wondered if anyone had any veiws on this idea, appaerntly is quite dense, then other people say carpet the walls, which i have since read is pretty useless for sound proofing, just want to spend my cash right! cheers Rich

Hi Rich. A belated "Welcome!". :) A few quick answers:

Im thinking 12mm exterior ply sheets to make the external walls, though 18mm if can afford but not sure if will make that much difference?

For isolation, yes, it will make a big difference. You have 50% more mass in 18mm vs 12mm, plus the boards themselves are more rigid, so you have more desirable resonant characteristics.

Then either 50mm polystyrene insulation

That is useless, acoustically, and the reason is simple to understand (but not often explained!) Polystyrene insulation is "closed cell" at the microscopic level, meaning that there is no path for air to get through. Only "open cell" insulation is any use, acoustically. Insulation acts to absorb sound by the tiny fibers inside "vibrating" in sympathy with the sound wave as it travels through. As the air particles inside the insulation vibrate, they cause the fibers around them to vibrate, thus absorbing some of the acoustic energy and turning it into low-grade heat energy. Polystyrene has no fibers, and no place for air molecules inside to vibrate. Therefore it does nothing much to absorb energy. Which makes it useless, acoustically.

(am told this is great for heat but useless for sound proofing!)

Exactly.

then 50mm rockwool, or would i be better just going for 100mm rockwool,

100,, rockwool is the best way to go. Rockwool is great for both thermal AND acoustic insulation, whereas styrofoam is only useful for thermal. If you do half-and-half, then you are wasting half the cavity, from the acoustic point of view. You'd be giving up somewhere around 5 to 10dB of isolation with the "half-and-half" plan. That's a lot!

again this is confusing between various websites,

Yup. There sure are a lot of places on the interne, that post ignorant myth with no scientific background. Very confusing. But you won't find that here: pretty much everything we say here is backed up by solid research, equations, papers, or empirical experience from some of the world's leading studio designers, going back many decades. So if you come across something here that you don't understand, then feel free to ask for the scientific explanation as to why it is so, and you'll get more info than you ever bargained for! :)

And Then two layers of plasteboard of different thinkness seperated by green glue?

Once again, the "different thicknesses are better" concept comes along! It's a myth. Or rather, a partial myth: Yes, using two materials of different thicknesses does have a slight advantage in increasing isolation... but only in the region of the spectrum know as the "coincidence dip", which is a rather complex phenomena related to bending waves and the speeds of sound in different materials. It just means that at some frequencies in the high-mid range, any given material while have an area where the isolation is LOWER than predicted by the simple equations of mass law. So if you use two different materials, then their coincidence dips are also different, and don't line up. That sounds great, on paper... until you realize that the effect is small, it is offset by the reduced mass (as compared to if you would have used the thicker material for both layers), and occurs in a part of the spectrum that is very well isolated anyway. So the overall effect is not important, and the increased mass really is important for the part of the spectrum where you really need lots of mass: the low end. In other words, forget the "different materials" concept. You don't need it, but you do need the mass, so go with two layers of the thicker material. And yes, do use Green Glue between them, if you need increased isolation in the low end of the spectrum. It works.

Again is plasterboard called sheetrock in the US?

Yup! Also called drywall, gypsum board, and probably several other things in different places, as well as some commercial names. It's all the same thing: basically, a slab of gyspum ("plaster or Paris") with thick paper facing on both sides. Very useful for acoustic isolation.

The floor im still unsure about, still pondering whether to fill my concrete perimeter with sand and pound it down level, will this help on the base?

Not sure I got that: Do you already have a concrete slab for your floor at present? Or do you just have a bare dirt floor with concrete foundation walls around it? If you are talking about using a layer of sand as the base before you pour your slab, then that is a possibility, but you should your local building code and common building practices in your area to find out how to do that. If you already have a concrete slab floor, then that's all you need. Nothing further required.

Also worried about moisure\condensation and have no clues about ventilation!!

Here too your local building code and local contractors can tell you the right way to seal the building in YOUR area. Probably involves membranes under the slabs, camp-proof layers under the upper part of the walls, and vapour barriers in the walls, as well as ventilation in the roof (attic space). Within the finished rooms you will also need a properly design HVAC system (Heating Ventilation Air Conditioning) to provide the necessary amounts of fresh air intake, stale air exhaustion, circulation, cooling/heating, and de-humidification. Notice I said "necessary": it really is! This is one area that often gets forgotten in studio builds, but is critical. You will need an HVAC plan of some type. And it will need to include silencer boxes to prevent sound transmission in/out/between your rooms.

Would love to be able to play this without bothering the neighbours, but it is loud when wound up!

The question is: "How loud?". You should answer that, by getting a sound level meter and actually measuring. Acoustics is a science, and like most branches of science, it is based on objective measurements, numbers and equations. You can't plug "really loud" and "not disturb the neighbors" into the equations for isolation! :) But you can plug in "100 dB inside" and "must be no more than 50 dB at the property line". That will lead to results that you actually can build, based on real objective science, not subjective guesswork. So get a meter (they are not expensive, and you will need it all the time anyway, for calibration) and measure how loud you are, and how quiet you need to be.

Still find the room within a room confusing! especially when dealing purely in timber.

It isn't that complex, really! It just looks that way... :) OK, so think of a common situation: someone has a garage that they want to turn into a studio. The garage has a concrete floor, four walls that consist of a timber frame with plywood and siding on the outside, and nothing on the inside (so when you stand inside the garage you see the studs), and a roof above: That is the "entire garage" if you are talking about it as just a garage, but it is only the "outer leaf" when talking about the future studio: So, to build a "room in a room", then that is exactly what you do: you build a totally separate, self-supporting room inside that garage. You build a second stud frame (four walls and a ceiling) that does not touch any part of the existing structure, then you put plaster board on only ONE side of that new stud frame. Bingo! You are done! That is your new "inner leaf". It is a "room" inside the existing "room". And it does not touch the existing room anywhere: it is designed to stand up all bu itself, and not need the outer leaf for support. It MUST be like that in order to work. There is a principle of physics involved here that makes the "outer leaf" plus the "inner leaf" plus the "air gap between them" into a system, know as a Mass-Sprin-Mass system. That is what causes the isolation to happen.

A friend of mine who built his studio years back said he lined the walls and roof with rooging felt??

That used to be the way it was done, many years ago, and in fact if you check the BBC research papers on studio acoustics you'll find that they used to recommend that a lot. But not any more. The science of acoustics has advanced, building materials and techniques have advanced, and there are better ways of doing things today. So you can skip the roofing felt.

then other people say carpet the walls,

:shock: :!: :roll: :horse: :!: Sigh! That one is till going around, I know. see it all the time. But you can safely ignored all web-sites and people who recommend that, since they actually do not have a clue about acoustics. It seems that this myth arose when someone noticed that cinemas often have carpeted walls, and cinemas often have great acoustics. So they think that it must be due to the carpet! But what they don't realize is that the carpet is just their for decoration, and is acoustically transparent carpet! All it does is cover up the REAL acoustic treatment that is behind the carpet, either on or in the walls. The carpet is just a relatively cheap, easy way to make the place look nice while NOT affecting the acoustic treatment. In reality, normal carpet (the type you use commonly in house, offices, shops, etc.) is very lousy for room acoustics: it does the exact opposite of what you need. Carpet is "Selective absorption", and randomly selective at that. It absorbs high frequencies quite well, some mids to a certain extent, and nothing at all in lows. Butt all small rooms need the opposite: lots of absorption in the lows, a fair amount in the mids, and very little in the highs. So carpet takes a bad room and makes it worse, acoustically. It will make your room sound dull, muddy and boomy. Bad idea.

which i have since read is pretty useless for sound proofing,

Yes, it is totally useless for soundproofing (more correctly called "isoaltion") and practically worthless for treatment, too. But isolation and treatment are also not the same thing: "isolation" means "stopping the sound from getting in or out", treatment means" making the room sound good". They are not the same thing, and in fact are almost opposite themselves! A room with no isolation won't need much treatment either, but a heavily isolated room will need LOTS of treatment, because the isolation itself makes the room sound bad.... Simple to understand: The isolation prevents the sound from escaping, thus keeping it inside, bouncing around. And a room that has lots of "sound bouncing around" is pretty lousy, acoustically: it is said to be "reverberant", and reverberant rooms sound terrible. So isolation and treatment are very different and are opposites, but they are often muddled together and mixed up in the minds and recommendations of those ignorant myth-monger web sites that I keep on mentioning: that just confuses people even more. - Stuart -

wow, thankyou for taking the time to answer my questions, brilliantly explained and very helpful! really appreciate any advise i can get before i start the actual build. So from your advice i take 18mm ply outer, 100mm rockwool insulation and two layers of plsterboard as thick as possible, would help to then plaster the inside walls? What i mean for the concrete base is i currently have a 1 metre rectangle perimeter, with a 1 metre concrete line running down the middle to help give the floor some support, so its not a solid conrete slab, due to the garden being way way off the road and up a steep slope, creating a conrete base would be difficult! So the concrete is above the soil level (stating the obvious!) must learn how to post pics! anyway, so is there any benefit of filling the base with anything, or should i keep an air gap, someone recommended i fill with shingle or something to help with soundproofing, i cant see this helping myself, but i am by no means an expert as you can tell! I have learnt quite a bit so far, and understand the sound isolation and sound treatment are different, ill get to the sound treatment part when i have the insulated structure built, i guess thats going to be a whole new ball game!! :) I will get a sound meter to measure my amp, completely understand about making it scientific, very loud doesnt mean alot! I will also want to record vocals without being heard, so guess thats a rough idea of my isolation needs Im curious to what could be acheived with my outer shell as described, then building a completely isolated room inside for guitar, do you think it would be worth the extra spend, its hard to imagine that a simple air gap would make that much difference, but again im not thinking scientifically! but then i am a guitarist! :) rich

100mm rockwool insulation and two layers of plsterboard as thick as possible, would help to then plaster the inside walls?

Yup! There's another option for the final finish, though: You build the inner-leaf walls "inside out", meaning that the plasterboard goes on the "other" side of studs, the side facing the cavity. So with all the walls finished, you still see the studs when you stand inside the room. That gives you the advantage of being able to use the space between the studs for acoustic treatment, so you don't need to plaster the plasterboard. The room treatment will most likely be a lot of absorption covered in cloth, so you can skip the time, effort and expense of plastering. That's one option, but it does mean that building the walls is a bit more complex. Obviously, you can't get inside the cavity to nail the plasterboard on! So you build the wall lying down flat on the floor, nail the plasterboard in place like that, then lift the wall into position. It's a common way of doing things around here, since there are acoustic advantages, but does add that complexity.

So the concrete is above the soil level

Ahhh! OK, got it. so your final concrete floor will be higher of the ground on one side, and lower on the other, but neither side will be touching the ground. OK, the issue here is "damping". Let me explain. As a guitarist, you know that if you pluck a string it will carry on vibrating for a loooong time, but if you touch it with your finger, even very gently, it will stop vibrating very fast. By touching it, you are "damping" the vibration. You do not want your floor to vibrate, obviously! You don't want your floor to act like a guitar string, or more accurately like a drum head, vibrating in sympathy with certain notes. Not a good idea. so your floor needs to be damped. If it is just suspended at the edges and not touching anything else, then it is, indeed, a drum head, and will vibrate. If it is sitting on the ground, then it will not vibrate, as it will be damped. Your idea of filling the cavity underneath with sand is one form of damping. So yes, if you do need good isolation, then you do need to damp your floor, and the sand fill is one good way of doing that.

must learn how to post pics!

Yup! Photos would help! :)

someone recommended i fill with shingle or something to help with soundproofing,

You could fill that space with building rubble, rock, shingles, or whatever else you happen to have, provided that it is very well tamped down, then covered with a layer of sand, plus the necessary membrane, before you pour the concrete. You do not want the fill to settle after the concrete is poured, as that would mean that your damping would no longer touch the slab. So it must all be tamped down very hard, several time, and left to settle before the pour.

ill get to the sound treatment part when i have the insulated structure built, i guess thats going to be a whole new ball game!!

Oh yeah! Even the ball is a different shape! And the rules come from another planet! :) Actually, the basic concepts are the same, just viewed from the other side of the table, so the perspective is different.

then building a completely isolated room inside for guitar, do you think it would be worth the extra spend,

That all depends on your "number"! The one you get from measuring how loud you are and how quiet you need to be. The types of construction that are open to you depend on how much isolation you need, and the type of construction is what defines how much you'll have to spend.

its hard to imagine that a simple air gap would make that much difference,

Yep, that doesn't make a lot of sense, until you realize that this is one case where "the whole is greater than the sum of the parts". Let me go into a bit more detail for you: There are only a very few basic ways you can stop sound: 1) You can put a barrier in the way that is so massive (heavy) that the sound waves cannot make it vibrate. Hard to do: any sufficiently loud sound will make any conceivable barrier move. There are no magical materials massive enough. 2) You can put a barrier in the way that is so rigid (stiff) that the sound waves cannot make it vibrate. Hard to do: any sufficiently loud sound will make any conceivable barrier move. There are no magical materials that are infinitely stiff. 3) You can remove all possible paths for sound waves to travel. Hard to do: you'd need to suck out all the air and create a total vacuum around your room! :shock: That's about it! #3 is out of the question, for practical reasons. #2 is a toughie, since very rigid materials are very expensive, and not perfect anyway. Which leaves mass. Mass is fairly cheap, but for high levels of isolation, you need so much of it that it gets hard to do. There is a natural law that governs how well mass isolates, and this is called (unsurprisingly) "mass law". It says that each time you double the mass mass of your wall, you increase isolation by 6 dB. This is a mathematical certainty, corroborated by numerous real-world experiments. All other factors being equal, wall that is twice as massive as its companion will have exactly 6 dB better isolation. In an ideal world, that is, such as a perfectly constructed wall measured under perfect conditions in a proper sound laboratory. In the real world, it won't be that good. Call it 4 or 5 dB, for most realist purposes. But let's assume you can get the theoretical best 6 dB. So, assume that you have a typical house wall with two layers of plasterboard (one on each side) that is getting you 30 dB of isolation. You pull out your sound level meter, check the legal requirements, and find out that what you need is 60 dB of isolation: Great! So you do the math: Double the mass by adding another two layers of drywall (total of four), and you will now have 36 dB of isolation. Double the mass again by adding another FOUR layers of drywall (total of 8) gets you to 42 dB. Double again (add eight more, total of 16)., and you get to 48.... I think you see where this is going! Mass law is not your friend. Sound intensity is an exponential thing: our ears work on a logarithmic scale, while mas law works on a linear scale. In order to get high levels of isolation for loud sounds, you need insane amounts of mass. Clearly, this is not good news! Fortunately, it turns out that there is another way. Instead of trying to stop sound with brute force, you can stop it by using itself to cancel itself: fighting fire with fire, if you wish. There is another principle of physics know as resonance that you can use to your benefit. Resonance is all about things that vibrate at their natural frequencies, and absolutely refuse to vibrate at any another frequency. You cannot make the E string vibrate at any other frequency, unless you re-tune it. It will resist you, very, very hard, because it ONLY wants to vibrate at that one single frequency: it rejects all others. So what if you could make your wall vibrate at only one frequency, so it would naturally reject all others? And then you tune that frequency so low down the scale that it doesn't matter? Tune it off the bottom end of the scale, for example? That way, it would resist all notes that you can hear! Brilliant idea! And yes, you can tune your wall to do exactly that: You use the principle of science known as "MSM" (for "Mass-Spring-Mass") to do that. You set up your wall as two pieces of "mass" with a spring in between, which is the most basic way to describe a resonant system in physics. And in acoustics, too. Lucky for us, air makes a very good spring, as far as sound waves are concerned. So if you trap some air between two layers of mass, you have a tuned system that will only ever vibrate at it's own natural frequency, and will naturally "fight back" if you try to make it vibrate at any other. And if you tune it low enough, it will not vibrate at ANY audible frequency. Bingo! So you set up one layer of "mass", such as a sheet of plywood on a frame, then leave a "spring", such as an air gap, then set up another layer of "mass", such as a sheet of plasterboard, and you have yourself a tuned wall that tights back! It now acts in your favor, and mass law went out the window! Now you have a very different set of equations to work with, and these really are your friends: with a two-leaf wall, you now get an increase of 18 dB in isolation every time you double the mass!! That is huge! So with a tuned two-leaf wall system, you can get very high levels of isolation with much less mass than you would need for a single-leaf wall: Much cheaper, and much better. So the air gap actually does make all the difference, because it is the "spring" in the tuned system. Very important. In fact, you ca do one more thing to improve the isolation even more: you an damp the spring! You can put insulation inside the wall cavity, which damps even that natural resonance that the wall would have had without it, as well as damping various other types of resonance inside the cavity: Adding some simple pink fluffy insulation inside the wall cavity can easily increase the total isolation by another 5 to 10 dB, over and above what you were getting from plain old MSM. So, like I said, "the whole is greater than the sum of its parts". Hugely greater. Air by itself is a lousy isolator. Insulation by itself is not much better. Mass is OK, but you need huge amounts under mass law. But put them together the right way, and man do you get results! So all you need to do know is to tune your wall correctly... :) - Stuart -

ok this is great advice, really starting to get a picture of the construction now and how to proceed! One other thing, a friend of mine can lay his hands on a huge ammount of sawdust, again reading through various blogs alot of people say packed tightly this is both a good from of insulation as well as acting as good soundproofing, though i would have thought it would have a low mass, maybe if packed tightly enough in cavity? Would probably bag it, as imagine it would be messy and prone to moisture?? Do you think any benefit? Was thinking as it would be free of adding it to the mass on the wall so as well as rockwool, but if likely to be yet another myth will save the hassle! So was kinda thinking exterior ply 18mm, 100mm rockwool, plasterboard (the innerleaf idea) sawdust (bagged in cavity), then another layer of plasterboard Rich

ill do some pictures when building starts! :D Rich

I'd be rather wary of using sawdust, even in bags. If there's any chance of it taking on moisture, expansion could cause undue pressure thus creating problems - wall stress not to mention flanking. It will settle over time leaving pockets so your insulation will not be uniform. It's a fire hazard and probably not even allowed for use as insulation.

yes i hear what your saying, and considered the same issues, but a friend of mine said he built his house and used sawdust for insulation and sprayed it with waterproof sealant, he did say it needs to be packed down well as does settle, but as a heat insulation says its fantastic, but not sure about as a sound isolation? I guess being a wooden structured shed its going to be flamable either way, though again seems a mixed report when checking online blogs etc (as usual!) contradiction everywhere you turn, it was purely that i can get hold of alot of it and wondered if worth utilizing in the construction to help build up the mass with hardly any cost involved :wink: typical musician trying to save money money! :) rich

he did say it needs to be packed down well

Then I can't see it being much use in a studio wall. That would create flanking paths very easily. Plus, I'm not aware of any research at all done on sawdust as acoustic insulation, so you'd be entirely on your own as to how it would perform: You'd be your own guinea pig. To be very honest, I'd forget that, and just go with tested and proven methods and materials. - Stuart -

hmmm not wanting to be my own guinea pig on a first time attempt! Ill stick with the rockwool! Just researching internal plasterboard and my local depot (wickes) do a 12.5mm soundsheild board, its a fair bit more expensive than standard plasterboard but if effective may well be worth the extra, there is no description as to why or what makes it better, just thats it is heavy ( a good sign i thought) anyone have any veiws, i could do one layer of this or two layers of 12.5mm standard, works out aorund same cost but no idea which would be more effective........ ps: am leaving the sawdust idea!! Rich

"Soundshield" is by Knauf. Density info is: 12.5mm = 12kg/m2 found this if it helps......more science! i understand an am9 flat13....but this know idea! But learning all the time, guessing its the mass factor again....

Normal Plasterboard weighs 8KG per m2 So am told, so surely two layers would be 16KG per m2 yet still cheaper than sound sheild board (just!) nut more effective, or am i missing the point somehwhere! rich

Normal Plasterboard weighs 8KG per m2 So am told, so surely two layers would be 16KG per m2 yet still cheaper than sound sheild board (just!) nut more effective, or am i missing the point somehwhere!

Yup! Cheaper mass is better mass. Nope! You didn't miss the point at all... :) You got it absolutely. There are no magical sound isolation products: they all have to obey the laws of physics in exactly the same way. Mass is mass, and the sound waves really don't care how much you paid for it! :) To be fair, that Soundshield is probably a good product, and probably does work as advertised, but the issue is cost / benefit: When you compare $ vs. $, does it provide more isolation per $ than plain old drywall (plasterboard)? Probably not. So go with the cheapest mass that will do the job. Ordinary fire-rated drywall is about the best deal you can get in most places around the world. By the way, 12 mm drywall (plasterboard) is too thin and too flexible to be highly effective for isolation. It is better to use 16mm drywall, which is thicker, more rigid, more massive, and has better overall isolation characteristics. 16mm fire-rated drywall should weight somewhere around 12 kg/m2. One layer of that is good, and two layers is fantastic. - Stuart -

Hey im back after working away for a few months, actually doing the music playing thing and not worrying about the music building thing! Anyway have now changed the base in which my studio is to be built upon, is now one solid concrete slab, I do feel this will be best. After some serious thought and sums, it seems that building out of blocks may be a better option than my initial timber idea, figure a 100MM block has an aweful lot more mass than 18MM ply sheets, also may weather better. But now this changes everything! sigh! Initially I thought possibly a double skin of block work with an air gap between, so lots of mass and isolation, but then for warmth and insutaion, I figured batten interior and insulate with rwa45 rockwool, then 2 layers of plasterboard (again lots of mass) would achieve great results compared to my initial idea. But then I read that im creating a triple leaf structure which is B..A..D. (seriously?) It lost me on explanation so ill take the science! So my new question is, and im seriously wanting to get this build starting now I have the base and some cash! 1) would I be better with a single block structure, then RWA45 rockwool, 2 layers of plasterboard 2) or...2 layers of block and no insulation? (just doesn't sound like it would be a warm place to work, but its this triple leaf idea that got me now Also there are so many choices of block, from aerated (cheapest) to high density, im guessing the high density ones are heavier and have more mass, but would it make that much difference in the end, as cost is doubled for high density blocks I did also wonder about a single block structure, battened and insulated with rockwool, but using these de-coupling devices to fit plasterboard, or have heard there is a product call fermacell which is superior as has more density, my god could it be anymore complex! My whole aim really is to be able to record my stereo guitar amp at reasonable volume, the nearest house is a good 20M away, but you know us musicians we like to work late! And why is it they say sound travels at night! Does the air lose mass! The final part of my jigsaw is the roof, if I go the block route and not the timber frame, though even now have read in threads that the difference is miniscule even though block has so much more density...will I ever get this! How do you bring the roof to the same spec as the blockwork? Obviously when timber sheets are used its all equal, but you cant block a roof, and don't want to waste all that building effort to find my sound just goes out into the night sky!!! Any help or info is much appreciated, am hoping to start building next month, will it be timber or block....decisions, decisions Rich

figure a 100MM block has an aweful lot more mass than 18MM ply sheets,

Oh yeah!!! :!: THe density of plywood is around 500 kg/m3 or so. The density of reinforced concrete is nearly five times higher, at about 2300 kg/m3. So 100mm of concrete would be about 230mg/m2, while 18mm of plywood is about 9kg/m2. Three layers of 18mm plywood will get you about 27 kg/m2, which is about the same as two layers of 16mm fire-rated drywall...

Also there are so many choices of block, from aerated (cheapest) to high density, im guessing the high density ones are heavier and have more mass, but would it make that much difference in the end, as cost is doubled for high density blocks

Lightweight cellular concrete can be down as low as 400 kg/m3... So check the actual weigh/density of things you plan to use before making any decisions. And if the blocks are hollow, then the density is much lower still....

but then for warmth and insutaion, I figured batten interior and insulate with rwa45 rockwool, then 2 layers of plasterboard (again lots of mass) would achieve great results compared to my initial idea.

That wont make it any warmer! The temperature inside will depend on how much heat you put inside, not what the walls are made of. Yes, materials have "thermal inertia too", so the block would take longer to reach the same temperature as the air inside than the drywall would take, but unless you are leaning against the wall all day, it's the air temperature the matters to you, not the wall temperature.

But then I read that im creating a triple leaf structure which is B..A..D. (seriously?) It lost me on explanation so ill take the science!

In fact, attaching battens to your concrete block wall then putting drywall on the battens is not only creating a third leaf: it is also creating a tuned panel trap (membrane absorber).

1) would I be better with a single block structure, then RWA45 rockwool, 2 layers of plasterboard

That would work too, provided that the plasterboard (= "drywall") leaf is fully decoupled from the block leaf.

2) or...2 layers of block and no insulation? (just doesn't sound like it would be a warm place to work, but its this triple leaf idea that got me now

Why do you not want to put insulation in the gap between the leaves for the block wall? The insulation is necessary to provide damping in the resonances within the wall cavity. You should not leave that out.

(just doesn't sound like it would be a warm place to work,

Like I said: the warmth you feel will be due to the air temperature inside, not the wall temperature. Besides, you'll need stacks of acoustic treatment on the walls anyway, no matter how you build it, and since most of that will be thick insulation, that will also be keeping the "warm" in.

My whole aim really is to be able to record my stereo guitar amp at reasonable volume, the nearest house is a good 20M away, but you know us musicians we like to work late!

You'll probably be fine with a good dense outer-leaf made of concrete block, plus an inner leaf consisting of a 2x4 stud frame with two layers of 16mm drywall on it. The framing CANNOT touch the outer-leaf concrete block anywhere, and it also cannot touch the outer-leaf ceiling joists anywhere.

And why is it they say sound travels at night! Does the air lose mass!

Nope, but at night the different temperature layers in the atmosphere can "bend" the sound waves, and cause them to arrive at places the would never get to during the day. Plus, the ambient noise level drops at night anyway: offices, shops and school shut down, far less traffic on the roads, people go to sleep and turn off their radios, TVs, phones etc. So it is just quieter in general, and sounds that you would not have noticed during the day are now very clear, since they are no longer being "masked" by other sounds.

The final part of my jigsaw is the roof, if I go the block route and not the timber frame, though even now have read in threads that the difference is miniscule

I'm not sure I agree with that: A concrete slab roof is going to be way better than a light timber framed roof, any day!

How do you bring the roof to the same spec as the blockwork?

That's pretty hard to do... If you have the option of a flat concrete roof or a timber-framed roof, I'd go with the concrete any day! - Stuart -