Hi there-
I'm in Hamilton, New Zealand, in the country (as such loudness/quietness not really a factor, as there are no neighbours to complain about it - so sound isolation per se not an issue).
I have a plan sorted for the control room,
just need a few questions answered for the recording room, which I am in the planning phase of, if you would be so inclined:
5m x 6.5m
2nd floor of square concrete building
concrete floor
concrete rear and right walls (will be building a second wood/foam wall over the concrete walls (a) for heat and (b) greater absorption)
left and front walls wooden/glass
roof corrugated iron on a 45 degree angle going from approx 5.5m to 9m height (will build a ceiling from wood, plasterboard and rockwool, probably at a height of 3.5m sloping upwards to 3.9m)
sound isolation not an issue due to it being in the middle of country, acoustic treatment is however.
Roughly fits 1:1.4:1.9 ratio.
Anyway, the questions:
1. With a recording room as opposed to a control room, is symmetry important?
2. Is altering the angle of the walls good for acoustics?
3. Carpet on floor vs no carpet on floor? I'd rather have carpet, for the purposes of comfort (don't care about spills).
4. What materials can I put up behind the wooden walls (left, front) to give symmetry with the opposite (right and rear, concrete + secondary wooden wall) - or does it (symmetry) not matter in this case?
5. Is a concrete floor problematic in any other sense (other than sound isolation which doesn't matter in this context)?
6. Have heard talk that an "infinite ceiling" (like what I've got essentially) can be beneficial for recording, then other talk that keeping everything in line with the correct ratios is best for acoustics. Which is wrong?
Thanks,
M
A few questions re: recording room
Originally posted at johnlsayers.com, topic 14585.
There is an announcement at the top of the forum about what to do to assure getting as many responses as possible.
The announcement leads to this post (click here). Actually, several people, who are experts on this forum, will most likely not reply if you don't do what is written in that post. Many others who are very helpful, will most likely not reply out of respect for the moderators' wishes.
Having said that, here are some comments on your post:
I can understand wanting to put thermal isolation there, but I don't see how building another wall would reduce "reflectivity". What do you mean be "reflectivity"?concrete rear and right walls (will be building a second wall over the concrete walls (a) for heat and (b) less reflectivity)
Neither. Both. It depends on what you are trying to accomplish. Since you seem to be talking about a live room, not a control room, I'd go for as much height as you can get, and make the room as large as you can in all directions. And if the ceiling is still too low for good recordings, then consider how you are going to treat it to improve that. But first get your ceiling as high as you possibly can. - Stuart -so there are no sounds around that you will need to stop? No wind, rain, thunder? No planes or helicopters flying overhead? No cars, trucks, tractors or other vehicles ever come close? No animals around (dogs, birds, cows, chickens, etc)? No other people around in the building? No radios, TVs etc elsewhere in the building? Etc.Control room: yes Live room: probably not, but it depends...1. With a recording room as opposed to a control room, is symmetry important?That depends what you mean by "good for acoustics". If you are talking about flutter echo, then yes, splaying walls can help with that. If you are talking about resonance and modes, then no, splaying walls wont help with that, and will just make things more complicated to calculate.2. Is altering the angle of the walls good for acoustics?Bad idea, for several reasons, and only one of them is "spills". You already have bare concrete, which is an excellent floor, acoustically, provided that you treat the rest of the room correctly.3. Carpet on floor vs no carpet on floor? I'd rather have carpet, for the purposes of comfort (don't care about spills).I don't understand the question. You don't put things "behind" walls to change room symmetry. It is the walls themselves that change the symmetry. So if you want symmetry, you will have to build inner-leaf walls t give you that symmetry. What you put "behind" the walls has no effect on symmetry (although it will certainly affect the isolation).4. What materials can I put up behind the wooden walls (left, front) to give symmetry with the opposite (right and rear, concrete + secondary wooden wall) -Nope! A concrete floor is great, provided that you don't cover it with carpet. If you don't like the look of concrete, then put ceramic tile on it, or laminate flooring. Both are good acoustically.5. Is a concrete floor problematic in any other sense (other than sound isolation which doesn't matter in this context)?6. Have heard talk that an "infinite ceiling" (like what I've got essentially) can be beneficial for recording, then other talk that keeping everything in line with the correct ratios is best for acoustics. Which is wrong?
Thanks, I did read through it, but not as thoroughly as I should have. The information I've supplied (now - have edited) is as much as I can actually provide given my limited building knowledge at present.There is an announcement at the top of the forum about what to do to assure getting as many responses as possible. The announcement leads to this post (click here). Actually, several people, who are experts on this forum, will most likely not reply if you don't do what is written in that post. Many others who are very helpful, will most likely not reply out of respect for the moderators' wishes.
Perhaps it should have read "greater absorption". Plan is to have the secondary wall, with limited reflectivity, some absorption, as opposed to concrete which is more reflective.I can understand wanting to put thermal isolation there, but I don't see how building another wall would reduce "reflectivity". What do you mean be "reflectivity"?
Overhead yes - rain and the occasional plane. The concrete sides of the building should take car of the rest. Hence the need to build a ceiling with plasterboard and rockwool (actually glasswool - pink batts - over here, but does exactly the same thing).so there are no sounds around that you will need to stop? No wind, rain, thunder? No planes or helicopters flying overhead? No cars, trucks, tractors or other vehicles ever come close? No animals around (dogs, birds, cows, chickens, etc)? No other people around in the building? No radios, TVs etc elsewhere in the building? Etc.
Depends On?1. Control room: yes Live room: probably not, but it depends...
Thank you - I've read about carpet being frequency 'hole-y', are there other reasons again?3. Bad idea, for several reasons, and only one of them is "spills". You already have bare concrete, which is an excellent floor, acoustically, provided that you treat the rest of the room correctly.
Okay - I guess I meant in the sense that (even if I put up solid wood) there's going to be a certain amount of transmission through to the concrete behind (through the wood itself) - which will give a different sound again to a solid wood wall with nothing behind it. SO I'm looking to equalize the absorption/reflectivity symmetry.4. I don't understand the question. You don't put things "behind" walls to change room symmetry. It is the walls themselves that change the symmetry. So if you want symmetry, you will have to build inner-leaf walls t give you that symmetry. What you put "behind" the walls has no effect on symmetry (although it will certainly affect the isolation).
So the best ratio's (houden's etc) don't apply for recording rooms in terms of modes? I mean, if I'm to stick with best ratios, the ceiling would be (as stated) about 3.5-3.9m. I can't make the width/length any larger, so would there any point to make the ceiling higher? And what are the advantages of an 'infinite' ceiling? Thanks for chiming in despite my lack of adequate info- Matt6. Neither. Both. It depends on what you are trying to accomplish. Since you seem to be talking about a live room, not a control room, I'd go for as much height as you can get, and make the room as large as you can in all directions. And if the ceiling is still too low for good recordings, then consider how you are going to treat it to improve that. But first get your ceiling as high as you possibly can.
Except for the most important item of all: the one that says "Nothing says "I didn't bother to read or follow these instructions" like leaving your profile location blank!"... :)The information I've supplied (now - have edited) is as much as I can actually provide
Well, that is two different things you are talking about there. Adding the wall won't change the acoustic absorption very much. There is hardly any difference at all between the absorption coefficients of concrete and drywall, for example. The only way to get great absorption for either type of surface, is to add acoustically absorptive material over it, such as fiberglass or mineral wool. You can do that to the existing concrete just as well as you can do it to an added sheetrock wall. They only two real reasons why you might justifiably want to add a wall are to improve isolation by creating a two-leaf MSM wall, or to splay the walls for RFZ or flutter echo control.Perhaps it should have read "greater absorption". Plan is to have the secondary wall, with limited reflectivity, some absorption, as opposed to concrete which is more reflective.
Actually, that isn't correct. All sides matter equally. Acoustically, the room does not act like four separate walls and a separate ceiling: Rather, it acts as one single unit. If you change any one part of it, then you change the whole. Sound waves bend around things that are smaller than they are, and low frequency waves are very large: much larger than your room. So you cannot hope to stop them by only treating one of the sides of the room. The entire room has to be designed to work together, or it wont work at all. I often use the analogy of an aquarium: you cannot build an aquarium with glass only three sides, cloth on the fourth side and cardboard on the bottom. It will not hold water. You have to put glass on all five sides. The same with your room. You have to treat all sides the same, or it won't "hold sound", the same way that a faulty aquarium won't "hold water". Acoustics is not intuitive.Overhead yes - rain and the occasional plane. The concrete sides of the building should take car of the rest.
That is only two parts of the three that you need. An MSM wall (the most cost-effective sound barrier possible for a studio) consists of two massive "leaves" separated by an air gap which is filled with wool. You are talking about only two of those. You also need to add mass to the other leaf: the existing roof.Hence the need to build a ceiling with plasterboard and rockwool
Depends On what you want to do with it! Symmetry might be useful for some things, but usually you don't need it in a live room. If you are only planning to record single instruments in there at a time, then probably not needed.Depends On?
Many others. For example, our brains are very used to "hearing" reflections off the floor at certain timings, because wherever you go in the entire world, the floor is always the same distance below your ears. Distance to walls and ceiling changes wherever you go, but the floor is a constant. Your brain has learned that your entire life, and is tuned to it. That "distance cue" is encoded on the sound that strikes your ear, and the sound that strikes your microphones. When your brain doesn't get that cue, it sounds strange. This is one of the reasons why it is so unpleasant to be in an anechoic chamber for very long: your brain gets no acoustic clues at all as to where the floor is, and it doesn't like that much. The data from your eyes conflicts with the data from your ears. Disconcerting. Almost as bad is if you have a soft floor and a hard ceiling above at an unusual distance: your brain isn't very good at telling "up" from "down" (even though it is really good at telling "left" from "right") so if your ceiling is at, for example, 60cm from the mics and from your ears (eg, overheads on a drum kit), but there is no acoustic "floor", then it just doesn't sound right. Your brain can tell something is wrong, and thinks that the ceiling is actually a "floor" in the wrong place. You might not be able to put your finger on what the problem is, but you'll notice that it just isn't "right". And there is no way to fix that in the mix. OK, so the effect isn't huge, and won't send you (or the people who listen to your mixes) wobbling around, looking drunk and falling over, but it is still there, subtly, and your ears can still notice that the instruments/mix/vocals just don't sound right, or don't sit exactly right together. In my philosophy, I want the best dam room I can afford, with everything as perfect as possible, to minimize all artifacts to the smallest possible expression. Ten minor sloppy things in my room design might not be much each by themselves, but add them all together and you could just end up with a problem. So I'm a perfectionist, down to every last details, for as much as my budget and room space will allow.Thank you - I've read about carpet being frequency 'hole-y', are there other reasons again?
Once again, that isn't really true. If you have two walls set up like that, then acoustically it is a two leaf system that acts as a single resonant unit, not as two separate walls. The entire system resonates at one frequency that is set (mostly) by the masses of the two leaves and the distance between them. Acoustically, everything inside the room only "sees" the surface of the inner leaf, and behaves more or less like there was only wall at that location with the combined properties of everything, and not like there is something behind that wall. In fact, all of your room ratios and dimensions should be taken ONLY from the inner leaf, not from the outer leaf. The inner leaf surface defines the room, not what might be behind it. The properties of "what is behind it" do come into play, yes, but only as far as making up part of the system which is the complete wall. (OK, so before some perfectionist climbs in and talks about perforated panels and such, I should clarify that I'm assuming a sealed, solid, rigid, massive inner leaf, not one with holes in it, nor one with very little mass, nor a flexible one, nor a limp mass, etc. :) just plain old drywall or maybe MDF, on studs, sealed.).Okay - I guess I meant in the sense that (even if I put up solid wood) there's going to be a certain amount of transmission through to the concrete behind (through the wood itself) - which will give a different sound again to a solid wood wall with nothing behind it. SO I'm looking to equalize the absorption/reflectivity symmetry.
I think you mean Louden, not Houden. :) Anyway, ratios still apply to live rooms, of course, but only if the room is a rectangle. If you splay some of the walls (as you often do for live rooms) then simple ratios no longer apply. You cannot figure out the room modes for a diamond-shaped room using ratios. Ratios only apply to six-sided rectangular rooms with roughly parallel walls. Even then, all that a ratio tells you is where the modes are in the room, and how they are spread out. That helps greatly in a control room, since your mix position is located at a know point within that "sea" of modes, and you want that point to be as neutral as possible. A live room is different: you might set up instruments, and mics anywhere at all in that room and you might even have several at once, each at a different location, in a different set of modes. And you will be tweaking all of that (mic positions and instrument locations) to get the best possible sound for each, which might well involve moving it into or out of certain room modes. You really don't care about modes when you do that: you only care about finding the position for the instrument and the mic that sound best, for that specific instrument with that specific musician and that specific mic. So modes aren't much of an issue in live rooms, IMHO (others might disagree!).So the best ratio's (houden's etc) don't apply for recording rooms in terms of modes?
Which "best ratios" are you referring to? Contrary to popular belief, there is no "perfect" ratio, nor even a handful of "excellent" ratios. Rather, there are actually a large number of really good ratios, that fall into several groups along a roughly diagonal line in X:Y space, with a couple of outlying islands around them. Each of those "really good" groups is surrounded by a larger area of "quite good" and "not so bad" ratios, and only when you get a long way outside of those neighborhoods do you get to the "Beware! dragons be here" ratios, that you really do want to stay away from. So, you can probably find a workable ratio that is reasonably close to your existing dimensions, and them maybe change one or two of your dimensions to get even closer to a good one. Provided that you are talking about a rectangular room, of course. If the room isn't rectangular, the ratios are out the window. For example, what ratio would you use to calculate the modes for a pentagonal room, or an octagon? Or even worse, a circular room? Anything outside of a rectangle simply cannot be figured out using ratios. In any event, 3.9 meters of height is pretty good. You should be able to do well with that.I mean, if I'm to stick with best ratios, the ceiling would be (as stated) about 3.5-3.9m.
An "infinite ceiling" is really just an ordinary ceiling treated with a very large thick layer of absorption, to try to disguise it acoustically, so that it seems to not be there, in the sense that reflections from it are minimized. But the concept is more applicable to very low ceilings, and at 3.9 m you should be fine. Probably normal treatment is going to be fine for that.And what are the advantages of an 'infinite' ceiling?
If you already have 3.9m, then probably not. Many folks here would happily commit murder to get such a height in their rooms! You'll find some people looking decidedly green as they read about your 3.9m room height.... :) I'm one of them! - Stuart -I can't make the width/length any larger, so would there any point to make the ceiling higher?
Firstly, thanks man, some super-informative stuff in here...!
Oh right - I put that in the top of my first post in the edit I did, but yeah-Except for the most important item of all: the one that says "Nothing says "I didn't bother to read or follow these instructions" like leaving your profile location blank!"... :)
I just meant that in terms of noise coming in, only the roof is a problem at the moment. Points taken however.Actually, that isn't correct. All sides matter equally. Acoustically, the room does not act like four separate walls and a separate ceiling: Rather, it acts as one single unit. If you change any one part of it, then you change the whole.Overhead yes - rain and the occasional plane. The concrete sides of the building should take car of the rest.
Gotcha. Yes that makes sense. Not necessary though, I think. In my current cottage I have the same sort of set up (corrugated iron roof, air gap, glasswool and plasterboard) and I don't hear the rain/planes in here, from above at least - I'm thinking an extra layer of plasterboard is overkill in this case- we don't get overly heavy rain here.That is only two parts of the three that you need. An MSM wall (the most cost-effective sound barrier possible for a studio) consists of two massive "leaves" separated by an air gap which is filled with wool. You are talking about only two of those. You also need to add mass to the other leaf: the existing roof.Hence the need to build a ceiling with plasterboard and rockwool
Right = probably needing to be able to record full bands at present, at once, when necessary (though that's going to be the lower end of the quality/payment schedule, obviously, so not too worried).Symmetry might be useful for some things, but usually you don't need it in a live room. If you are only planning to record single instruments in there at a time, then probably not needed.
Thanks - and interestingly I got told yesterday that with the local anechoic chamber, 1 in 5 people gets spontaneously uncontrollably nauseous for that same reason.For example, our brains are very used to "hearing" reflections off the floor at certain timings, because wherever you go in the entire world, the floor is always the same distance below your ears. Distance to walls and ceiling changes wherever you go, but the floor is a constant. Your brain has learned that your entire life, and is tuned to it. That "distance cue" is encoded on the sound that strikes your ear, and the sound that strikes your microphones. When your brain doesn't get that cue, it sounds strange. This is one of the reasons why it is so unpleasant to be in an anechoic chamber for very long: your brain gets no acoustic clues at all as to where the floor is, and it doesn't like that much. The data from your eyes conflicts with the data from your ears. Disconcerting.
Right - so better to have a soft(er) ceiling and a hard floor?Almost as bad is if you have a soft floor and a hard ceiling above at an unusual distance: your brain isn't very good at telling "up" from "down" (even though it is really good at telling "left" from "right") so if your ceiling is at, for example, 60cm from the mics and from your ears (eg, overheads on a drum kit), but there is no acoustic "floor", then it just doesn't sound right. Your brain can tell something is wrong, and thinks that the ceiling is actually a "floor" in the wrong place. You might not be able to put your finger on what the problem is, but you'll notice that it just isn't "right". And there is no way to fix that in the mix.
Well thank god someone is, I don't have the time/energy to be, so someone else doing it is good :)So I'm a perfectionist, down to every last details, for as much as my budget and room space will allow.
But louden's such a silly name for an audio designer! ;)I think you mean Louden, not Houden. :) Anyway, ratios still apply to live rooms, of course, but only if the room is a rectangle. If you splay some of the walls (as you often do for live rooms) then simple ratios no longer apply. You cannot figure out the room modes for a diamond-shaped room using ratios. Ratios only apply to six-sided rectangular rooms with roughly parallel walls.
Cool, good info.Even then, all that a ratio tells you is where the modes are in the room, and how they are spread out. That helps greatly in a control room, since your mix position is located at a know point within that "sea" of modes, and you want that point to be as neutral as possible. A live room is different: you might set up instruments, and mics anywhere at all in that room and you might even have several at once, each at a different location, in a different set of modes. And you will be tweaking all of that (mic positions and instrument locations) to get the best possible sound for each, which might well involve moving it into or out of certain room modes. You really don't care about modes when you do that: you only care about finding the position for the instrument and the mic that sound best, for that specific instrument with that specific musician and that specific mic. So modes aren't much of an issue in live rooms, IMHO (others might disagree!).
Oh cripes, don't start murdering me, or I'll never get the studio done! Thanks - it's an old cheese room (appropriate) in the crumbling remains of a dairy factory - all of the other buildings have been taken over by various businesses, except this one- gonna take a lot of work. Cheers man- keep it coming m@If you already have 3.9m, then probably not. Many folks here would happily commit murder to get such a height in their rooms! You'll find some people looking decidedly green as they read about your 3.9m room height.... :) I'm one of them!
Then you'll probably be OK with one layer. What you can do is to build the structure to take two layers, then put up one initially and test, to see if it is enough, before deciding if you need the second layer or not. But as long as you seal up both leaves tight and have enough mass on the outer leaf, then you should probably be fine with one, if isolation isn't a big deal for you. (On the other hand, you'd only be saving the a few bucks by not putting the second layer on... :) )I'm thinking an extra layer of plasterboard is overkill in this case- we don't get overly heavy rain here.
Yup! That's part of the secret mantra that all studio builders must chant at least fifty times per day... "Soft ceiling, hard floor, no three leaf, seal everything, more mass, treat then test... soft ceiling, hard floor, no three ..." )Right - so better to have a soft(er) ceiling and a hard floor?
No problem! How about if you post some basic layouts (in SketchUp format) of what you have and what you are thinking of, so that folks here can take a look and make more suggestions. Photos are also useful. As they say around here: "No photo means it didn't happen". - Stuart -keep it coming