Hi all
First post here, though I've read a fair number of threads on this site and I'm sure this is the right place to be! Before I start, I'd just like to say that all help will be gratefully received as my head is swimming a bit with all the information there is out there on this topic. I've been researching the subject for around 2-3 months now and I think I've understood a fair bit (I have Rod's book, plus "RA:The Book", which is also great - if staggeringly expensive - and a couple of others) and the planning stage appears to be absolutely key - the last thing I want to do is spend tens of thousands of pounds on internal construction, only to get it wrong. All that will happen is that bands will turn up, once, realise the isolation is poor and then never return (I know I would). I simply cannot afford for that to happen, hence I really want to get this right!
So, to explain; I am planning to open a five room, commerical rehearsal/recording facility locally. I have found a (reasonably) suitable site, a 2,400 sq ft, single storey industrial unit, located a long way from any residential property. The unit is a typical small industrial premises; three-phase power, personnel door, separate vehicle entrance, concrete floor (presumably a fairly thick, reinforced concrete floor as it's designed to take industrial equipment, but I've not had this verified yet), brick walls, corrugated roof. It is on a pleasant enough development and the parking is good - not something you always get with rehearsal sites in the UK.
I have planned for five rooms in all, four for rehearsal only, one for rehearsal or recording, plus a separate control room.
I've attached a plan (apologies, it's done in Excel(!) not exactly the ultimate drawing tool - but hopefully you'll get the idea).
To clarify a few points on the plan;
1) The doorways are shown, but no doors. Please just take it as read that there are two doors per doorway, separated by a gap.
2) I've left the gridlines in on purpose to demonstrate size, one grid square is 6" square.
3) Each studio wall is shown as being 1' thick (it is shown as a solid wall, but is in fact a two leaf system, explanation follows). This is the main point of my post. I have, so far planned on each of the five rooms being its own, double skinned entity. Specifically, an outer leaf of 110mm high-density concrete blocks, then a gap (filled with mineral wool), then a triple layer of 15mm plasterboard on metal or wood studwork. Each separate studio is then separated (both from each other, and from the outer shell of the building) by a 6" air gap. However, from several posts I've read on this forum recently, I'm now questioning if this is the right thing to do as the adjoining wall between (for example) studios 3 and 4 would appear to equate to a four leaf system - am I correct in assuming this? If so, should I redesign what I have, with each individual studio only having a single leaf? If so, I'd probably go with the same HD concrete blocks as I would have used on the outer leaf, but laid on their side, giving a wall width of 215mm or 8.5".
The reason that my current plan assumes that each studio should have two leaves each is that the rehearsal studio my band uses now has been constructed in that way and the isolation is very good. But, it may simply be that the rooms there are separated by such a distance (the smallest gap is about 3.5') that each the 2 x two leaf systems can no longer be considered as a whole 4 leaf system (I really hope this is making sense!).
Obvioulsy my wallet is very keen on the idea of only needing to construct a single leaf per room, but getting it right is paramount.
Next big question (and I've read plenty on this but would still very much appreciate any clarification possible); the premises has a concrete floor, one I suspect that is capable of taking very significant loads. I will be renting the space so I cannot disturb the floor as per the instructions shown in Rod's book. As such, would a sand filled wooden deck be a suitable option - at least for the rehearsal only spaces?
Actually, I know I'll need to address the floor and ceilings too, but if someone could give me the answer to the single-or-double leaf question re the walls for now, then I can re-do my plans and move on to the floors and ceilings thereafter!
Last note: apologes if I've left anything pertinent out - please let me know if so and I'll do my very best to tell you as much as I know.
Many thanks in advance for all your help!
Jon
Five room commercial rehearsal/recording studio plans - help
Originally posted at johnlsayers.com, topic 18148.
Hi Jon, and welcome to the forum! :)
It would help to know two rather important things:
1) What are your design goals, in terms of isolation? In other words, who many decibels of transmission loss do you need)
2) What is your budget for this project? (There are different methods and materials that can be used to build studios, some costing more than others.)
Try SketchUp (Google it). It is a 3D modeling program that will make your life very much easier. What you did in Excel must have taken a lot of work, considering that it was never designed for that purpose!(apologies, it's done in Excel(!) not exactly the ultimate drawing tool - but hopefully you'll get the idea)
As you suspect, that would be a 4-leaf system. Not a good solution. It would probably work (despite the four-leaf effect), simply due to the sheer mass and rigidity in those walls, but you'd spend an awful lot more than you need to on materials and labor.This is the main point of my post. I have, so far planned on each of the five rooms being its own, double skinned entity.
ExactlyI'm now questioning if this is the right thing to do as the adjoining wall between (for example) studios 3 and 4 would appear to equate to a four leaf system -
Yes.am I correct in assuming this?
Assuming that your outer-leaf fully encloses the "set of inner leaves", then yes. So basically you would need to build a wall across the building to section off the area where these rooms will be, then build each room as it's own single-leaf structure. Think of it like having a shoe box in front of you, and placing several large matchboxes inside it, not touching each other or the shoe box. That's exactly the concept.If so, should I redesign what I have, with each individual studio only having a single leaf?
Ignorance abounds about acoustics, all over the internet, and even some supposedly professional studio design companies places with multiple leaves, through not understanding he basic principles of acoustics. Believe it or not, there is even one example right here on the forum of a company that design and built a studio that has as many as SEVEN leaves in some places. It works, of course, simply due to the humungous amount of mass involved, but it cost the owner a lot, lot more then it needed to. So just because you see a place built in a certain manner does not mean that the design is good, efficient, effective, or economically sound... :)The reason that my current plan assumes that each studio should have two leaves each is that the rehearsal studio my band uses now has been constructed in that way and the isolation is very good.
That is still a four-leaf system, despite the distance, but it works because it is tuned to such a low frequency that it isolates everything, and has enough mass to overcome the deficiencies in the design. But it also cost way more that it needed to...But, it may simply be that the rooms there are separated by such a distance (the smallest gap is about 3.5') that each the 2 x two leaf systems can no longer be considered as a whole 4 leaf system (I really hope this is making sense!).
Not necessary. That's a concrete "slab on grade" floor you have there, so it is massively heavy, and thoroughly damped by the earth itself. That's a great floor to have in a studio. Unless you have extreme isolation needs, there's no need to add extra mass to it. You might want to consider building drum risers in each room, to keep the drums off the floor, but that's all you really need to do.Next big question (and I've read plenty on this but would still very much appreciate any clarification possible); the premises has a concrete floor, one I suspect that is capable of taking very significant loads. I will be renting the space so I cannot disturb the floor as per the instructions shown in Rod's book. As such, would a sand filled wooden deck be a suitable option - at least for the rehearsal only spaces?
And the doors, and the windows, and the seals, and the HVAC system, and the electrical system... Isolating a room is "all or nothing": everything that goes into it has to be though trough carefully, and the design has to consider everything working together at ones, all at the same level of isolation, rather than separate pieces, each doing its own thing. - Stuart -Actually, I know I'll need to address the floor and ceilings too,
Hi Stuart - thanks for the welcome!
To (attempt to) answer your questions;
1) I do not yet know exactly how much isolation I require. I have now purchased a sound level meter (this was recommended somewhere on this site so I went out and go it yesterday) and I'll take it to a rehearsal on Saturday. Presumably I measure the sound level inside the room when the band is playing, then measure outside when (the rest of the band) is still playing, then subtract one reading from the other to find the isolation I need. The reason I'm using the studio we're using on Saturday as the benchmark is that they'll be my chief competition and so I need to be as good as them or better to make sure people want to use my studio again. I've used a fair number of rehearsal facilities in Essex now and for the most part they seem okay (not good, just okay), but the isolation between rooms is almost always poor and it really annoys me - I want to hear my band, not the band next door!!
2) Budget? Well the unit itself will be rented, so no capital outlay there apart from rental and business rates (not exactly insignificant, but P&L, rather than cap ex). In terms of what I have available just to build out the interior, I've allowed around £50k.
I'll give SketchUp another go - I recall trying to use it for a home extension project a few years ago and found it, er, less than easy (and I've worked in IT for years with all manner of apps) but I will give it another try!
"So basically you would need to build a wall across the building to section off the area where these rooms will be, then build each room as it's own single-leaf structure" - some thoughts here. The absolute, overriding prerequisite is that a band in one room should not be able to hear a band in another room. What happens outside these rooms i.e. in the corridors and other common areas in sound terms comes a fairly distant second. So, presumably the walls and ceiling of the building can be classed as the outer leaf - is this right? If so, presumably I could augment the ability of the building walls/ceiling to offer sound insulation to reduce the sound travelling to neighbouring properties. The other consideration is that space is fairly tight and building a whole extra outer leaf might not be possible without seriously compromising the design - some of the rooms are a bit marginal on size as it is, 17' x 12' is not entirely miniscule, but I wouldn't want it any smaller.
So, assuming I've understood you correctly, I will have to make some fairly serious single leaf rooms to give me the best chance of keeping sound from leaking between them. Initial thoughts are high-density concrete blocks (laid on their sides to give a wall width of 215mm/8.5') with a double layer of 15mm plasterboard either side and green glue between the two layers of plasterboard and the concrete wall (both sides). I'm aware (again from this site) that I'll need to build a balanced system and there's little point in having great walls if the ceiling is not of a similar spec, and the doors, windows etc, but would this be a good start - for the walls at least?
Crazy isn't it, I've been reading and reading around the subject, but I just reached a point where I couldn't seem to finalise the plan as I needed to have my thinking verified. I'm very glad I did as the plan looks very different and probably more cost-effective now!
Many thanks again (eagerly awaiting response!)
Jon
That will tell you how much isolation you are getting right now, which might or might not be how much you need. Apart from your own personal goals, there are very likely also legal requirements on how much isolation you must have to the outside world. Check with you municipality for their noise regulations. So in addition to taking readings inside and outside with the band playing, also take readings without them playing, to see what the noise floor is in that location.Presumably I measure the sound level inside the room when the band is playing, then measure outside when (the rest of the band) is still playing, then subtract one reading from the other to find the isolation I need.
Sounds like "par for the course" with average rehearsal spaces! :) So if yours is better isolated, with a more comfortable atmosphere (ie, good HVAC) and better acoustics, you'll be able to compete rather well with the others...but the isolation between rooms is almost always poor and it really annoys me - I want to hear my band, not the band next door!!
For a 2400 ft2 space, that works out to around £20 per square foot. Perhaps a bit on the low side, but maybe doable if you are doing all the labour yourself, or can barter labour for studio time, or some such. It also depends on how much of that space will actually be "acoustic" space (needing isolation, treatment, etc), and how much is just "utility" space (bathrooms, offices, halls, chill-out area, storage, etc.).In terms of what I have available just to build out the interior, I've allowed around £50k.
IT does have a rather steep learning curve, and some "unusual (! :shock: ) ways of doing things, but once you get past that it turns out to be a powerful tool. Take a look at some of the tutorial videos on YouTube, etc. to get you started. There's another, major, overriding issue hear: sound is 3D, not 2D. Studios are 3D, not 2D. There's no way you can do 3D design in Excel!I'll give SketchUp another go - I recall trying to use it for a home extension project a few years ago and found it, er, less than easy (and I've worked in IT for years with all manner of apps) but I will give it another try!
Yes, but you cannot isolate the rooms from each other unless they are also isolated from the rest of the world, as a group. At least, you can't do it at a reasonable cost using just simple two-leaf construction.The absolute, overriding prerequisite is that a band in one room should not be able to hear a band in another room. What happens outside these rooms i.e. in the corridors and other common areas in sound terms comes a fairly distant second.
Yes, but you still need to section off the actual "studio" part of that from the "utility" part. So for example, if you have a rectangular space overall, then decide how much of that at one end will be studios, and build a wall across that section, with your utility space on one side and the studio space on the other. Now you have the outer-leaf for the studios completed. So all you need to do is to build each of the studios as a single inner-leaf. That way, you have two leaves in all directions, from all studios, both to each other and to the outside world.So, presumably the walls and ceiling of the building can be classed as the outer leaf - is this right?
Well, "sort-of-but-not-really"... It's not quite that simple. A two-leaf wall is a tuned system, so you can't really speak about the outer leaf doing one thing while the inner leaf does something else: they interact, and work together as a system: The whole is greater than the sum of its parts.If so, presumably I could augment the ability of the building walls/ceiling to offer sound insulation to reduce the sound travelling to neighbouring properties.
You don't need to build an entire new outer-leaf: It is already there, mostly. Or rather, three sides of it are there, and you only need to build the forth side to separate it from the utility area.The other consideration is that space is fairly tight and building a whole extra outer leaf might not be possible without seriously compromising the design
There are many ways of saving space in studio design... :) Some aren't so obvious at first.some of the rooms are a bit marginal on size as it is, 17' x 12' is not entirely miniscule, but I wouldn't want it any smaller.
That's basically it, provided that the outer leaf is already in place. The leaves act together, as a system, not so much individually. If you don't build that extra wall to close you off from the utility area, then your bathrooms, halls, offices, foyer, etc will be in your "air space", which means that the sound will be deafening in there for your staff and customers, and in addition each time you open or close a door, the isolation will change / disappear. Probably not what you want to happen!So, assuming I've understood you correctly, I will have to make some fairly serious single leaf rooms to give me the best chance of keeping sound from leaking between them.
That sounds like a three-leaf wall to me, not a single leaf! Single leaf would be just the concrete blocks, period. That's all you need: So each room would be built as a single-layer concrete block wall, period. A 21cm concrete block wall is going to give you pretty darn good isolation! The density of concrete is roughly 2200 kg/m3, so if those blocks are either solid or cement filled, the surface density of the wall will be on the order of about 47kg/m2. Two of those with a 25 cm air space between them, filled with the right insulation, will have a fundamental resonant frequency of about 17.7 Hz, so they will start isolating at 24.7 Hz, isolate everything above 35 Hz quite decently, and will isolate really well above about 53 Hz. Rough theoretical estimate of isolation is around 60 dB, minimum. Your biggest issues will not be the walls: they will we doors and HVAC. Isolating doors and HVAC to more than 60 dB is not easy.Initial thoughts are high-density concrete blocks (laid on their sides to give a wall width of 215mm/8.5') with a double layer of 15mm plasterboard either side and green glue between the two layers of plasterboard and the concrete wall (both sides).
I understand you perfectly! The more you learn about acoustics, the less sure you become about your plans, as you start to realize that there's a humungous number of things that go into the design, and they all seem to be interacting with each other, while also joining forces to thwart your best efforts at achieving decent isolation with decent sound insides the rooms! But "hang in there", as the yanks say: Pretty soon things will start to fall into place and make more sense. - Stuart -I've been reading and reading around the subject, but I just reached a point where I couldn't seem to finalise the plan as I needed to have my thinking verified. I'm very glad I did as the plan looks very different and probably more cost-effective now!
Hi Stuart
Apologies for the tardy response - it's been a very busy week!
I really appreciate your responses - I have a few questions/comments re some of them if I may, as follows;
Our playing peaked at 115dBC. On average though, it was closer to 108-110dBC. With no-one in the room (apart from me!) the level was approximately 41dBC - no other room was occupied so that figure is the lowest it will ever be. Annoyingly, I didn't get to take a reading outside the room i.e. in the common area. We're back there tonight, so I'll take some more readings (as you suggested) as there will almost certainly be several other bands in this evening. Ideally I'd like to figure out what the isolation is between rooms, but the only way I can see I'll manage this is to be in one room with no noise created therein with a band playing in another room. This will give at least a rough idea of how good the isolation is. I will also check on the noise regulations with the local council."That will tell you how much isolation you are getting right now, which might or might not be how much you need. Apart from your own personal goals, there are very likely also legal requirements on how much isolation you must have to the outside world. Check with you municipality for their noise regulations. So in addition to taking readings inside and outside with the band playing, also take readings without them playing, to see what the noise floor is in that location."
Out of 2400sq ft, only 1225 sq ft will be acoustic space, the rest is corridors, bathrooms etc and I do envisage doing a very significant amount of the work myself. Note: I have not yet made the leap to SketchUp - it's coming!For a 2400 ft2 space, that works out to around £20 per square foot. Perhaps a bit on the low side, but maybe doable if you are doing all the labour yourself, or can barter labour for studio time, or some such. It also depends on how much of that space will actually be "acoustic" space (needing isolation, treatment, etc), and how much is just "utility" space (bathrooms, offices, halls, chill-out area, storage, etc.).
Please see a fairly heavily revised plan for the studio below (still in Excel, as yet). The red outline is the 'shoebox', with all the individual rooms ('matchboxes') contained therein. Due to space constraints, the toilets and corridors are within the outer leaf, so this is the way it'll have to be, but I don't believe it will be a huge problem for clients, provided that the isolation between rooms is very good. Am I getting closer to the inner/outer leaf design described?Yes, but you still need to section off the actual "studio" part of that from the "utility" part. So for example, if you have a rectangular space overall, then decide how much of that at one end will be studios, and build a wall across that section, with your utility space on one side and the studio space on the other. Now you have the outer-leaf for the studios completed. So all you need to do is to build each of the studios as a single inner-leaf. That way, you have two leaves in all directions, from all studios, both to each other and to the outside world.
Surely the outer-leaf (the shoebox) is of no value to the bands in each room? For them, the two leaf system comprises the single leaf of one room, the gap between the two rooms, and the single leaf of the other room i.e. 8.5" of concrete, air/insulation, 8.5" of concrete. The outer leaf of the studio as a whole (the shoebox) isn't involved in this at all, is it? Apologies if I've mis-interpreted something here, but I'm assuming the 'shoebox' outer-leaf is there solely to keep sound out of the communal areas (albeit that with the space available I simply cannot do this to any great degree) and to stop sound escaping from the building as a whole.That's basically it, provided that the outer leaf is already in place. The leaves act together, as a system, not so much individually. If you don't build that extra wall to close you off from the utility area, then your bathrooms, halls, offices, foyer, etc will be in your "air space", which means that the sound will be deafening in there for your staff and customers, and in addition each time you open or close a door, the isolation will change / disappear. Probably not what you want to happen!
Is the reason this would be viewed as a three leaf system be because there would be a small air gap between the concrete wall and the first layer of plasterboard? If the walls were covered with a sinlge layer of wet-plaster instead, would this then constitute a single-leaf? To clarify; 8.5" concrete block wall, with plaster render on either side. This would add yet more mass, and would look less utilitarian! The concrete blocks used to build the walls would be solid, high density blocks.That sounds like a three-leaf wall to me, not a single leaf! Single leaf would be just the concrete blocks, period. That's all you need: So each room would be built as a single-layer concrete block wall, period.
- would I be right in assuming this would be mineral wool? For instance, between rooms '3' and '5'? Will the gap between rooms only being 6" have a very detrimental effect on isolation? (hoping for a "no", expecting a "yes" :? )filled with the right insulation
I can well believe it! I would assume HVAC would be the worst - you build an air-tight room, then punch big holes in it to let air in and out! Havn't addressed this yet, but will do so very shortly. I know this is akin to asking "how long is a piece of string?", but would it be reasonable to say that and overall isolation of 60dB would be considered good for a rehearsal space? On the subject of ceilings for each of the individual rooms (matchboxes), My plan is to have joists of the appropriate strength (8"x3" or similar) with 3 layers of plasterboard affixed to the underside to form a ceiling for the room (obviously sealed/caulked etc). Above the plasterboard, between the joists, I will have 8" of mineral wool insulation. Two questions here; 1) does this description sound reasonable, and 2) how would you protect the insulation as it's open to the 'shoebox'? Would it be appropriate to cover it with some form of thin plastic sheeting to impede the ingress of water? My major concern is that if the building's roof sprang a leak, it would go straight into the mineral wool and from there to the plasterboard below that. I'm hoping I'm on the right lines at least here, but I'd be very grateful if you could tell me if I've missed something obvious - or even not obvious! That's all for now. I'll not leave it so long to reply next time, apologies again. Best regards JonYour biggest issues will not be the walls: they will we doors and HVAC. Isolating doors and HVAC to more than 60 dB is not easy.
Great! So you got yourself an answer: in your case "silent" means about 40 dBC, and "loud" means about 110 dBC. So if you really want to shoot for maximum isolation, you would need to go for 70 dB of TL. That can be done, although not easily, but with concrete block walls you might just make it. At such high levels of isolation, you are approaching the flanking limit if the floor anyway, so it's not worth shooting for more than that. Also, at those high levels of isolation, doors, windows HVAC and electrical become critical elements, and those will require some very careful design. For example, as you said, installing HVAC means that you have to punch huge holes in your expensive isolation walls, thus negating everything you worked so hard to achieve! So those "holes" clearly have to be done right, with beefy silencer boxes on them. Ditto electrical system.Our playing peaked at 115dBC. On average though, it was closer to 108-110dBC. With no-one in the room (apart from me!) the level was approximately 41dBC - no other room was occupied so that figure is the lowest it will ever be.
OK, that makes more sense. So we are talking more like £40 per square foot. That sounds more realistic.Out of 2400sq ft, only 1225 sq ft will be acoustic space, the rest is corridors, bathrooms etc and I do envisage doing a very significant amount of the work myself.
That's the general idea, yes.Please see a fairly heavily revised plan for the studio below (still in Excel, as yet). The red outline is the 'shoebox', with all the individual rooms ('matchboxes') contained therein.
That's fine if you really want to do it that way, but it does have some major implications. First, you will have to acoustically isolate your plumbing system too, since all the pipes drains and air vents have to penetrate the outer leaf to get to the outside world. That increases your cost considerably And you also need to add additional HVAC, separate from the Studio HVAC, or at least carefully designed, so that you don't end up with unpleasant bathroom odors permeating your control room and live room.... :) :shock: :? :!: And you have the additional expense of isolating rooms that really do not need it. So you might need to increase your budget some more. You will also be losing a huge amount of space in isolating each of those rooms. You really should not go this way: the bathrooms and will end up tiny.Due to space constraints, the toilets and corridors are within the outer leaf, so this is the way it'll have to be, but I don't believe it will be a huge problem for clients, provided that the isolation between rooms is very good.
It sure is of value to them! Without it, they don't have any isolation to or from the outside world. With no outer leaf, their isolation to the outside world is now simply nothing at all. See below:Surely the outer-leaf (the shoebox) is of no value to the bands in each room?
It is important to understand that the inner-leaf and outer-leaf are NOT two different things: they are part of the same system, and work together. It is not the case that the outer leaf stops some sound and the inner leaf stops the rest: Both leaves work together, as a tuned resonant system, to isolate the rooms: They no not really act separately. Saying that the outer leaf isn't necessary for the musicians is like saying that the drum shells are not necessary for the drummer, since it is only the drum heads that make the noise. Or that the guitar body is not necessary for the guitarist, since it is the strings that do the vibrating, so all you need is a neck. Obviously, to have a drum you NEED not just the head, but the shell as well! Without that, you don't have a drum at all. Ditto for the guitar: without the body, there is no guitar. And it is the same with your isolation system: if you take away part of it, then you are left with nothing useful. So you MUST have the outer leaf in place, or you won't have any isolationApologies if I've mis-interpreted something here, but I'm assuming the 'shoebox' outer-leaf is there solely to keep sound out of the communal areas (albeit that with the space available I simply cannot do this to any great degree) and to stop sound escaping from the building as a whole.
Exactly. A "leaf" is just any large massive surface that is next to an air gap.Is the reason this would be viewed as a three leaf system be because there would be a small air gap between the concrete wall and the first layer of plasterboard?
That would be a single leaf, yes. And it would be a great isolator, since the plaster will help to seal the concrete surface. Concrete is porous, so it needs to be sealed.If the walls were covered with a sinlge layer of wet-plaster instead, would this then constitute a single-leaf? To clarify; 8.5" concrete block wall, with plaster render on either side.
Excellent! More mass = more isolation, and the plaster adds a bit more too, plus the seals.This would add yet more mass, and would look less utilitarian! The concrete blocks used to build the walls would be solid, high density blocks.
Either mineral wool or fiberglass. Both work really well for that: If mineral wool, then the density should be about 50 kg/m3: Of fiberglass, then around 30 kg/m3.- would I be right in assuming this would be mineral wool?
I'd have to do the math to be certain, but 6" sounds like a reasonable gap for what you are talking about. There is one VERY important point here, with using two-leaf brick walls: as the builders are building, normally the mortar squishes out the back, and drips down inside the wall cavity. And the brick layers often drop debris in there, such as broken bricks, pits of wood, dried mortar, and anything else they don't need. You CANNOT allow that to happen, as it can potentially form bridges between the leaves. So your bricklayers need to work slowly and carefully to make sure that no mortar or other debris falls into the cavity. Very important!Will the gap between rooms only being 6" have a very detrimental effect on isolation? (hoping for a "no", expecting a "yes")
Yup, that is, indeed, the issue! :)I can well believe it! I would assume HVAC would be the worst - you build an air-tight room, then punch big holes in it to let air in and out!
That is a realistic goal, yes.but would it be reasonable to say that and overall isolation of 60dB would be considered good for a rehearsal space?
Possibly, but not necessarily. Think about this: Concrete weighs about 2300 kg/m3, roughly. Drywall weighs about 700 kg/m3. so concrete is about three times heavier for every cm of thickness. Three layers of 16mm drywall will be 48mm thick and weigh roughly 34 kg per square meter. On the other hand, your concrete block walls will be 215 mm thick, and therefore will weigh about 500 kg per square meter. Notice the difference? Each square meter of wall is about fifteen times more massive than each square meter of ceiling. Do you see the issue? The ceiling will be your week point here. Then there is another issue: the roof itself. The roof is the "outer leaf" of your ceiling, so it too needs to have similar mass in order to isolate to the same level.On the subject of ceilings for each of the individual rooms (matchboxes), My plan is to have joists of the appropriate strength (8"x3" or similar) with 3 layers of plasterboard affixed to the underside to form a ceiling for the room (obviously sealed/caulked etc). Above the plasterboard, between the joists, I will have 8" of mineral wool insulation. Two questions here; 1) does this description sound reasonable,
Water??? :shock: :!: There should never be any possibility of water in there. If water gets in., you would never know... until the mould had reached a stage where it is just too late to do anything, ... The roof needs to be absolutely, certainly sealed, and needs to have sufficient mass to complete the outer-leaf of the studio. I suspect that you will need to beef up the roof and also seal it amazingly. What is the roof made of right now? - Stuart -and 2) how would you protect the insulation as it's open to the 'shoebox'? Would it be appropriate to cover it with some form of thin plastic sheeting to impede the ingress of water?
Hi Stuart
Many thanks for your last reply. Apologies, but I have yet more questions!
I understand the doors and HVAC will be critical elements, but (and please excuse yet another daft question) why will electrics affect the isolation? Is it just from the point of how the electrics enter/exit each room? Presumably conduit stuffed with mineral wool and then sealed at each end? I'm seeing the HVAC company soon - hopefully they'll be familiar with silencer boxes etc. If not, I guess I'll need to find another company.Great! So you got yourself an answer: in your case "silent" means about 40 dBC, and "loud" means about 110 dBC. So if you really want to shoot for maximum isolation, you would need to go for 70 dB of TL. That can be done, although not easily, but with concrete block walls you might just make it. At such high levels of isolation, you are approaching the flanking limit if the floor anyway, so it's not worth shooting for more than that. Also, at those high levels of isolation, doors, windows HVAC and electrical become critical elements, and those will require some very careful design. For example, as you said, installing HVAC means that you have to punch huge holes in your expensive isolation walls, thus negating everything you worked so hard to achieve! So those "holes" clearly have to be done right, with beefy silencer boxes on them. Ditto electrical system.
I was about to write something about not really getting what you mean, but I think I might! Are you saying that if the bathroom (for instance) is in between the inner and outer leaf, then it may - via the extractor fan, soil pipe etc - leak sound from within the air cavity to the outside world? Hence the need to isolate it/them accordingly? Could the HVAC feeding the studios not also feed the air cavity too? Or is this just asking for trouble as it will allow the ducts to become conduits for sound? Presumably this is where the careful design comes in! Just so I can get it clear in my head, which rooms will result in me losing considerable space due to the need for their individual isolation - the bathrooms? I may have a way around this (as I've re-drawn the plan again).That's fine if you really want to do it that way, but it does have some major implications. First, you will have to acoustically isolate your plumbing system too, since all the pipes drains and air vents have to penetrate the outer leaf to get to the outside world. That increases your cost considerably And you also need to add additional HVAC, separate from the Studio HVAC, or at least carefully designed, so that you don't end up with unpleasant bathroom odors permeating your control room and live room.... And you have the additional expense of isolating rooms that really do not need it. So you might need to increase your budget some more. You will also be losing a huge amount of space in isolating each of those rooms. You really should not go this way: the bathrooms and will end up tiny.
Understood - it must be a two leaf system which works as a tuned pair. My point was only that isolation between rooms (to stop bands hearing each other) is fundamental for me. Obviously I need to keep sounds of the outside world isolated too (both for users of the studio and for my neighbours!), but the "between rooms" issue is paramount. Given that is the case, surely the two-leaf system between rooms is; one 8.5" concrete wall, 6" of mineral wool, then another 8.5" concrete wall. The 'shoebox', in this scenario, effectively doesn't exist and isn't involved between rooms i.e. from the interior of one room to the interior of another room. That was the point I was attempting to make, but I'm not sure I explained myself very well, apologies! If I'm talking complete rubbish, please let me know (wouldn't be the first time - especially on here!).It is important to understand that the inner-leaf and outer-leaf are NOT two different things: they are part of the same system, and work together. It is not the case that the outer leaf stops some sound and the inner leaf stops the rest: Both leaves work together, as a tuned resonant system, to isolate the rooms: They no not really act separately. Saying that the outer leaf isn't necessary for the musicians is like saying that the drum shells are not necessary for the drummer, since it is only the drum heads that make the noise. Or that the guitar body is not necessary for the guitarist, since it is the strings that do the vibrating, so all you need is a neck. Obviously, to have a drum you NEED not just the head, but the shell as well! Without that, you don't have a drum at all. Ditto for the guitar: without the body, there is no guitar. And it is the same with your isolation system: if you take away part of it, then you are left with nothing useful. So you MUST have the outer leaf in place, or you won't have any isolation
So, having established that, would there then be any benefit in adding a layer of plasterboard over the top of the wet-plastered walls, using Green Glue? Or would I just be burning money for no discernible benefit here?That would be a single leaf, yes. And it would be a great isolator, since the plaster will help to seal the concrete surface. Concrete is porous, so it needs to be sealed.
Understood! Rod makes this point several times in his book too - I guess this is something that happens all too easily unless you're watching the builder like a hawk.There is one VERY important point here, with using two-leaf brick walls: as the builders are building, normally the mortar squishes out the back, and drips down inside the wall cavity. And the brick layers often drop debris in there, such as broken bricks, pits of wood, dried mortar, and anything else they don't need. You CANNOT allow that to happen, as it can potentially form bridges between the leaves. So your bricklayers need to work slowly and carefully to make sure that no mortar or other debris falls into the cavity. Very important!
Again yes, I've considered this but the costs always seem to slow me down! I guess the best option would be a concrete beam and block ceiling which would have far more mass per square metre. I've not investigated how much this would cost as I'm suspicious it would be significantly more than joists and plasterboard. But, if it's going to let the plans down then I guess I should revisit this. At least the spans I'm planning aren't huge (biggest is 14'). The roof is, according to the sales brochure "double skinned, insulated, with translucent roof panels" - not many of the latter though, maybe 20%. It's a pitched roof formed from steel beams - a typical small industrial unit (in the UK, at least). I would say the double skinned panels are steel looking at the photos, though I can't be sure. When you say the roof needs to be sealed, I assume that's a) sideways so that no sound escapes to either neighbouring property, and b) vertically so that no sound escapes through holes/vents there? And lastly (and I feel some more expense coming on!), could you give me some idea of what might typically be required to beef up the roof please? I am so grateful this site exists, there is a collosal amount to learn just about studio construction. It sounds simple when you first think about it, but the deeper you dig, the less you find you know :? :shock: Many thanks for all your help. Best regards JonPossibly, but not necessarily. Think about this: Concrete weighs about 2300 kg/m3, roughly. Drywall weighs about 700 kg/m3. so concrete is about three times heavier for every cm of thickness. Three layers of 16mm drywall will be 48mm thick and weigh roughly 34 kg per square meter. On the other hand, your concrete block walls will be 215 mm thick, and therefore will weigh about 500 kg per square meter. Notice the difference? Each square meter of wall is about fifteen times more massive than each square meter of ceiling. Do you see the issue? The ceiling will be your week point here. Then there is another issue: the roof itself. The roof is the "outer leaf" of your ceiling, so it too needs to have similar mass in order to isolate to the same level.
Exactly. You have to have at least one penetration of your expensive isolation walls to get the power in, so that has to be done carefully, in two senses. One you already figured out:why will electrics affect the isolation? Is it just from the point of how the electrics enter/exit each room?
Yup, that's one. the other is the actual conduit itself: it creates a flanking path between the leaves, so it needs to be decoupled. You cut a small section out of the middle of that conduit, in between the two leaves, and replace that with rubber. You also cannot just run straight across the gap between the leaves: that would put the two penetrations right opposite each other, a potential weak point. So you bring your conduit through the outer leaf, then immediately curve it 90° to run parallel to the leaf for a good distance, then curve it 90° again to go through the inner-leaf. Y chop the decoupling section out of the "parallel" part, and wrap that gap with rubber sheeting, such as EPDM or Neoprene. Electrical tie-wraps or plumbing hose clamps keep it in place.Presumably conduit stuffed with mineral wool and then sealed at each end?
:lol: Yup! An HVAC contractor who doesn't know about silencers should not be allowed anywhere near your studio!!! :)hopefully they'll be familiar with silencer boxes etc. If not, I guess I'll need to find another company.
Yup! You can't have rooms inside your "air", and you certainly can't have holes in the leaves.but I think I might! Are you saying that if the bathroom (for instance) is in between the inner and outer leaf, then it may - via the extractor fan, soil pipe etc - leak sound from within the air cavity to the outside world? Hence the need to isolate it/them accordingly?
Nope! The air cavity is a hermetically seal, air-tight "space" between the leaves. No air going in or out. It HAS to be sealed in order to isolate. And it has to be sealed on BOTH leaves. This is a fundamental part of the MSM isolation system. Yes, a leaf still acts as a leaf even if it is not sealed, but in order to isolate, it must be sealed. The single most important thing you can do to an average room in your house to "soundproof" it, is to seal it truly air-tight. Do that, and you'll be amazed at how much the isolation improves. Even a tiny crack in the seal loses isolation drastically. Here's an experiment you can do: get in your car, drive to a really noise place, and close all the windows. Listen for a while to the sound coming in from outside. Now open your window just a tiny little fraction, just enough so you can see a paper-thin gap: notice the huge difference in sound level? That's a very small gap, but a big reduction in isolation. That should convince you how important perfect air-tight seals are.Could the HVAC feeding the studios not also feed the air cavity too?
Yep! :)Or is this just asking for trouble
Yep!Presumably this is where the careful design comes in!
Move your "red line" so that it outlines only the rooms that need isolation. The other rooms should be outside of that. The "red line" does not have to all be concrete block (although it would be ideal). You could also maybe build parts of that with woof framing and drywall. However, block would be the best.Just so I can get it clear in my head, which rooms will result in me losing considerable space due to the need for their individual isolation - the bathrooms? I may have a way around this (as I've re-drawn the plan again).
Yes, but you can't have one without the other. Think of a fish tank: even though you might only want to look at the fish from the front, you still need glass on the sides and at the back! Otherwise the water won't stay inside very well... :)My point was only that isolation between rooms (to stop bands hearing each other) is fundamental for me.
... and if it doesn't exist, then you don't have a two-leaf system on that side of the studio! Even though the rooms will have some walls that face each other across a small gap, and are therefore proper two-leaf walls, some walls of each room would NOT have another leaf facing them across the gap, if you take away the "shoebox". So those walls are not two-leaf MSM systems, and therefor do not isolate. Your isolation in each room is only as good as the weakest part. So if you have two walls that isolate to 60 dB, one that isolates to 50 dB, and one that isolates to only 20 dB, well then your total isolation is only 20 dB. And you wasted a lot of money on doing the other sides to 50 or 60! :) That's the issue here. Isolation is an "all or nothing" proposition, just like the fish tank. Leave out one piece of glass, or replace one piece of glass with cardboard, and guess what happens... :) So you cannot leave off part of the "shoebox". If you do, then none of the rooms have isolation: you'll just have a bunch of fish tanks next to each other with glass on some walls, and paper on other walls: none of the fish tanks will hold water....but the "between rooms" issue is paramount. Given that is the case, surely the two-leaf system between rooms is; one 8.5" concrete wall, 6" of mineral wool, then another 8.5" concrete wall. The 'shoebox', in this scenario, effectively doesn't exist ...
I understand what you are saying, but acoustic isolation doesn't work like that, unfortunately. It would be great if it did, but the laws of physics are against us here... :(That was the point I was attempting to make, but I'm not sure I explained myself very well, apologies!
Not really. The tiny increase in mass would have very little effect on the total isolation. Just plaster the concrete and leave it at that.So, having established that, would there then be any benefit in adding a layer of plasterboard over the top of the wet-plastered walls,
:shot: :lol: :!:Or would I just be burning money for no discernible benefit here?
Oh yeah! To a bricklayer, the wall cavity is synonymous with "garbage can"... :)I guess this is something that happens all too easily unless you're watching the builder like a hawk.
Welcome to the world of studio building! Take the number you first thought of for your budget, double it, add yesterdays date, divide by a very small fraction, multiply by a very large random number, add a few zeroes, and you are getting close to what it really costs... :)Again yes, I've considered this but the costs always seem to slow me down!
:shock: The "translucent roof panels" don't sound very hopeful! My bet is that they are just thin polycarbonate or some such... I very much doubt they are thick laminate glass! Hmmm....The roof is, according to the sales brochure "double skinned, insulated, with translucent roof panels" -
YEs, and yes. Once again, hermetic seals on all leaves are critical.When you say the roof needs to be sealed, I assume that's a) sideways so that no sound escapes to either neighbouring property, and b) vertically so that no sound escapes through holes/vents there?
Anything that adds useful mass at low cost: Drywall, MDF, plywood, OSB, etc. As long as you can get sufficient mass up there, and a good air-tight seal, it doesn't really matter what the specific material is.could you give me some idea of what might typically be required to beef up the roof please?
Oh yeah! And then some. The more I learn, the more I realize how little I know, and how much more I still need to learn! Each time I study some new aspect of acoustics, I realize that there's even MORE to know. So I'm actually getting dumber, not smarter as I learn! If I keep this up for a few more decades, I hope to become a total blithering idiot! :) Seriously, acoustics really is a much bigger subject that most people realize when they first get involved, and as you learn, you really do figure out that there is a lot to learn, and everything is interconnected. Realistically, it takes several months of daily study to get a good handle on it. At least it did with me. And I'm still learning, years later. And still studying. But hang in there: it does start to come together eventually... - Stuart -there is a collosal amount to learn just about studio construction. It sounds simple when you first think about it, but the deeper you dig, the less you find you know
Please see below the re-revised plan - hopefully this is pretty much in line with what you've said in previous posts, please let me know if you can see anything that's obviously amiss, as I really want to start getting quotes from the trades.
Many thanks
Jon
Yep, that's the idea!
But I would suggest a layout change here: the control room is far too small to be practical, and the shape is all wrong. I would make the control room bigger, and put it more centrally: switch places with rehearsal room #2, and adjust the sizes of the other rooms accordingly. The control room needs to be much bigger than it is now, and arranged so that the desk faces a short wall, and thus the speakers are firing down the longest axis of the room.
I would also try to vary the dimensions of the rehearsal rooms, so they are not all the same shape and size: you might get some sympathetic resonance going on between rooms, if the dimensions and volumes are identical.
Just a couple of thoughts!
FWIW.
- Stuart -
Why would you put double doors on a single concrete block wall?
Okay, I've rearranged the rooms, making the control room as suggested (which I originally wanted but couldn't figure out how to attain!). I've not been able to get the control room to be more central, I just can't see how the building shape/size will allow it as the central corridor leading to the fire escape must remain. I have, however, tried to make the control room symmetrical for mixing/mastering purposes which it wasn't before. Here it is;
The rooms are now slightly different sizes also (albeit that the 12.5' dimension still appears a lot), with the exception of 1 and 4 which are the same, but they are the furthest from each other. Not perfect, but space is tight.
Re the point about double doors on a single concrete wall, I guess the answer is that the doorway to each room will be a potential weak point. To make the door have the same mass as the walls would require some pretty impressive hinges and would be hideous to make/hang correctly etc. Two doors seemed the easier solution. Yes, this is a two leaf point, but a single, eight inch thick high-density concrete door is just not practical!
All comments gratefully received - thank you so much for your help so far!
Cheers
Jon
A two leaf is what we shoot for. But in this respect, depending on how wide that corridor/hall way is, it could be a four leaf, known to reduce the transmission loss and give a reduction in isolation.Two doors seemed the easier solution. Yes, this is a two leaf point, but a single, eight inch thick high-density concrete door is just not practical!
The corridor between studio '1' and the control room is 5'6" wide.
The corridor between studio '2' and studio '5' is 4'6" wide, but the doors are not opposite each other which should help.
The corridor between studios '3' and '4' is 7' wide.
Yes, the two sets of each double door could be classed as a 4 leaf system, but hopefully one that's worth having to give the best isolation per room!
Many thanks
Jon
With solid core doors and proper seals, I would spend my money in other places.
That's just me. And the concern that this might be a commercial environment, then you have to deal with handi-cap (ADA) regulations.
Just things to consider my friend.
I agree with Brien: With massive solid core doors, good seals, and those large air gaps, I think you will be fine. Just make the doors very heavy, and put at least two full perimeter seals all around each door.
- Stuart -