Hello everyone! First of all, thank you for your interest and clicking this thread :)
A little overview before getting started: my name is Victor, I have been playing drums since I was quite young and since a couple of years back I've been interested in setting up my own recording and rehearsing space. I was in the process of building my own studio in my home country five years ago, however due to some political sh** hitting the fan back home, I left to start a life elsewhere. Suffice to say I'm ready to get back into drumming and revive the dream of having my own studio.
Now, five years ago I didn't know about this forum, so I feel like I am starting from scratch but with proper access to knowledge this time! Thank you all for the information that you provide here!
Anyways, now to the good stuff. My project is centered around transforming a basement space (what is now being used as a wine cellar) into a decent enough room to record drums. As of now, I don't think there is a need to separate the live room from the control room, although the space is there to do so in the future. I would rather start off with a treated room for the drums that sound nicely where I can record from within, as a personal project, and later on think about expanding that and making the control room from an existing room adjacent to the wine cellar. Another important thing is that I want to attenuate the sound as much as possible to avoid disturbing neighbors as well as anybody else inside the house. Good thing is that since the space is in the basement, we have a couple of thick, cement walls that will help.
Currently I am still in the researching phase for the whole project. I am going over a bunch of threads in the forum and taking heed of all the advice (beeros05 story was particularly enlightening), however I must confess that I am pretty much a newbie in all of this.
I have taken the liberty of designing the space in Sketchup, hopefully you guys can take a look at it so you can see what I am working with, and then I will move on to the questions.
In the previous image, we can see the layout of the room. This is the outermost structure, which gives us a total length of approximately 7.43m, a width of 2.88m, and a height of 1.95m. This results in 21.39m^2 and 41.72m^3. In the next image, I have taken into consideration some limitations of the room such as some drainage pipes and the strangely shaped wall used to house the wines.
As we can see, we have two sections where we have a couple of water pipes running across both the length and the width of the room. I have yellowed out the space that completely walls off the pipes, so if we were to take the yellow areas as the limits of the room, the pipes would not affect the internal structure. Fortunately, the pipes aren't either too big or too many, so hopefully we can make use of that yellow space and just insulate around the pipes.
On the opposite end of the room, in red, there is a 32cm thick wall (not too sure of the material, could be brick or clay, unfortunately I have no idea. All I know is that it is pretty sturdy). This wall is rather interesting because it is full of holes used to store the bottles of wine. I am not sure if this will be useful for the build, although I guess not. I do not think we can count this wall a leaf in the mass-air-mass design. Behind this wine wall however, we have a very good cement wall that is part of the foundation of the house, so it is just cement engulfed by ground. The next image aims to take a look at the structure of the outer walls.
Hopefully this image gives a better look at the context of the room. Thankfully, we have a couple of really good walls due to being in a basement. Relative to the image orientation, the left and rightmost (labeled water pipes and wine wall) walls are very sturdy. These are cement foundation walls and there is nothing but earth after them (this is probably very wrong as I know nothing about construction, but we are underground and I imagine the cement of the walls runs out somewhere :P)
On the wall closest to the bottom we might have some issues. It is still cement, but it is in contact with my neighbor's basement wall as well, so this might be a relatively weak point in the overall structure. Unfortunately I have no way of knowing how thick this wall is.
In the top walls (next to the Door label) is where I believe I will have the most trouble. The wall with the door gives way to a room and it is only 7cm of concrete thick. Banging on the wall with my hand obviously does not feel as sturdy as the foundation walls, and the vibrations can be felt from the other room. Then, we have a green section that is adjacent to the stairwell. This concrete wall is also very sturdy, and is a minimum of 30cm thick. Following that wall, we have another thin, 8cm thick concrete wall which gives way to another room, which additionally, has a small hole in the wall near the ceiling (66cm long, 33cm wide). This hole might be trouble, but I've been thinking could be good for the HVAC (still need some more research around this area).
It is worth noting that the floor is also concrete.
The wall layout of this space makes me bring up the following question:
Can/should the concrete foundations be used as the outer leaf for a two leaf wall? Between the two leafs we would have the water pipes and the idea would be to place insulation in this gap.
I am attaching two more images with a 3d perspective just to give a better feel for the room. I will also attach actual pictures as a comment to this thread.
Now that we have some context...
I would like to take a well though-out approach to completing this project. I would rather take my time, take acoustic measurements (REW or whichever other tool), get an understanding of modes and frequencies, and adapt, than to rush it and botch the project. Of course, since I don't have much knowledge, this could take some time, but I think it is a good opportunity to do a full step-by-step guide for anybody in a similar situation and back every design and construction decision with facts and data. Of course, this is where I come to this forum and to you guys because I am kind of at a loss with the amount of information here. I am not quite sure where to start! I have a couple of hunches, like measure the dB level in the room when I play, however I will not have a drumkit with me until 2-3 weeks. Currently I only have a snare and some cymbals on me.
Some other information: the drainage pipes occasionally make a sound from the water rushing through them, but it is not a big deal. What worries me the most is the humidity. I would like to measure the humidity of the room given that it is a basement, and well obviously, because of the water pipes. I would not want any mold issues or damages to the gear, however I suspect that this won't be an issue due to this house being built like this for over 25 years and not having any humidity issues in the past.
I guess the first tangible objective would be to come up with a design that would minimize the sound escaping from the room. Hopefully the thick concrete walls already in place will help with that. To achieve this goal, I guess my first question would be what I asked previously, whether I can use the thick concrete walls on the left and bottom as the outer leafs of the structure and the airgap where the water pipes are, and prop up another wall as the second, inner leaf? What about the rightmost wall with the holes for wine? This one is also backed by a concrete wall, but how will this "wine wall" affect that mass-air-mass model? Finally, regarding the weakest 7cm and 8cm thick concrete walls, what can we do here? This area needs the most attention also because the door is there, and most of the sound will likely escape through here.
I am looking at a budget of 5k euros (hopefully, but can be adjusted over time if necessary) to get the space in good conditions. This includes sound proofing and treatment. Hoping this is within reason!
Quick summary of the situation:
Goal is to transform a space in the basement into a recording/rehearsing drum room
There are water pipes in the room. Humidity might be an issue, will look into measuring this.
One of the walls was used as a place to stash different bottles, so it is full of holes. Cannot make any changes to this wall.
The ceiling is a bit low at 1.95m.
Most of the walls are strong concrete, but there are some thin ones that will be problematic.
Sorry if my thoughts are all over the place, hopefully someone can help to steer me in the right direction. As of now, besides research a lot more, is there any data I can start gathering to help with the design of the room? If I am missing any information, let me know and I will be happy to provide it! I am looking forward to keeping this thread as detailed as possible for anyone that bumps into this!
Drum rehearsal/recording basement studio in Madrid
Originally posted at johnlsayers.com, topic 21999.
Follow-up pictures!
Hi Victor!
You said you need isolation. What that means is that you cannot have any voids in your leaves in terms of surface density. If any of your walls have too little surface density you have to beef them up by adding mass. Also, you cannot have any spots for potential leakage. That means you need to seal every crack/gap.
Issues I see with your room are is the obvious hole in the wall and all of the pipes. You will have to fill that hole and box in the pipes using a material that has the correct surface density to maintain your isolation.
What is your ceiling made of? Concrete? If it is sheet rock, I'd suggest removing the sheet rock so that your ceiling is taller (acoustically). You'd then just have to add mass to the underside of the subfloor. If it's concrete, that sucks in terms of acoustic height, but it's good for surface density!
In order to get great isolation, you will need a fully decoupled inner leaf. I'm afraid your ceiling will be extremely low after you build your inner leaf ceiling.
Lastly, you need to design an appropriate HVAC system for your room. You can kind of plan for acoustic treatment of the room, but your main priority here has to be designing the isolation and HVAC portion of your drum room. You have to be aware that low ceilings and instruments such as drums result in not great acoustics. But any room is better than no room!
Greg
Hey Greg, thanks for your quick reply!
You said you need isolation. What that means is that you cannot have any voids in your leaves in terms of surface density. If any of your walls have too little surface density you have to beef them up by adding mass. Also, you cannot have any spots for potential leakage. That means you need to seal every crack/gap.
Correct. First I want to deal with isolation to avoid possibly disturbing my neighbors. And yeah, obviously some major issues are the hole in the wall and the water pipes. However I do not really mind the sound that can be generated from the water pipes too much (leaking sound when it is raining, for instance). Would it be sufficient to ignore the pipes and just cover that gap with insulation? I mean if I find a reliable way to box them in in order to avoid the sound that would be great, but that is another big problem on it's own. I am not exactly sure how to find that "correct surface density" for the material to box them in. Regarding the hole in the wall, that is another big issue of course, and I am still thinking of a solution to it. Also, regarding the wall used to store the wine that is full of holes. The wall itself is sturdy, but the holes are a problem. How would this wall fit in to the MAM model, knowing that right behind it there is a very thick concrete wall that hopefully we could take advantage of? Since the wall has a lot of holes (air), could we consider it as the air portion of the MAM? Will filling the holes with insulation help at all?Issues I see with your room are is the obvious hole in the wall and all of the pipes. You will have to fill that hole and box in the pipes using a material that has the correct surface density to maintain your isolation.
The ceiling is concrete, no sheet rock here. So yes, good for isolation, not so good for acoustic height. Guess we will have to see how that impacts the drum sound later on...What is your ceiling made of? Concrete? If it is sheet rock, I'd suggest removing the sheet rock so that your ceiling is taller (acoustically). You'd then just have to add mass to the underside of the subfloor. If it's concrete, that sucks in terms of acoustic height, but it's good for surface density!
Since the ceiling is very thick concrete, do you think the decoupled ceiling will be a good tradeoff for insulation vs. height? I'm thinking sound won't be able to escape very well through that thick concrete ceiling, but I'm just speculating. Still need a lot of reading up.In order to get great isolation, you will need a fully decoupled inner leaf. I'm afraid your ceiling will be extremely low after you build your inner leaf ceiling.
Of course, I think if we start off with a good foundation regarding plans for isolation and HVAC, we can experiment with acoustic treatment later. Could you maybe give me some pointers on where to go next regarding planning the isolation? I've been thinking of reading up on Rod Gervais' home studio construction book, to get a better overall understanding of everything, but if there is another thing I should be aiming for first I would really appreciate your guidance. Should I do REW measurements now? Or should that wait until we are working on the acoustic treatment? Any advice is greatly appreciated. Thank you, Greg!Lastly, you need to design an appropriate HVAC system for your room. You can kind of plan for acoustic treatment of the room, but your main priority here has to be designing the isolation and HVAC portion of your drum room. You have to be aware that low ceilings and instruments such as drums result in not great acoustics. But any room is better than no room!
Hola. I think a viability study would be wise. Find out how much isolation is needed, and put some sort of estimated price on it.
Use a high powered speaker system, PA or DJ rig. Play Music or even an isolated drum track very loudly in the Basement. Measure the level, let's for 100-110dB Z Weighting.
Now measure the levels escaping. In your own and all your neighbours' homes. If you cannot have access, measure at likely weak spots, windows, doors, ventilation holes.
https://www.cdc.gov/niosh/topics/noise/app.html
There is a hungry elephant in the room here. The ceiling height. It is unfortunately even lower than typical the EU 2.45.
There is just not enough height to consider sound isolation AND treatment over head.
So let us find out how much sound travels up through that concrete floor.
DD
Hey Dan, thanks for taking the time to look into this.
I also agree with the viability study, that would give us a good starting point. I will try to see if I can perform the test as you state and get back with results. My drums should arrive in about 2 weeks, but maybe I can find some good speakers to produce 100-110dB.
Yeah... unfortunately the ceiling is quite low /: If it is really as bad as both you and Greg seem to be pointing out, we may have an alternative however. Next to the wine cellar (which is the room with the low ceiling we are discussing), there is an adjacent room with a more normal-sized ceiling. The measurements are as follows: Length: 3.2m Width: 2.7m Height: 2.4m Ceiling height is much better here of course, but the room is smaller overall. Also, we only have one wall that is thick cement, so isolation will likely be costlier to do here. Of course, I'm not very well versed in all of this so I don't really have a great understanding on the impact of the low ceiling on the acoustics of the room regarding the drums. Even then, I would assume the wine cellar is better suited for the drums than this adjacent room next door, because it already has some pretty thick walls built in although the acoustics might suffer in the end due to the ceiling. Maybe we can offset the damage done by the ceiling ~somewhat~ with treatment later down the road and get something decent? Suffice to say I know I won't get grade A++ recordings from the spaces I have available :P Thanks guys!There is a hungry elephant in the room here. The ceiling height. It is unfortunately even lower than typical the EU 2.45. There is just not enough height to consider sound isolation AND treatment over head.
These pipes are weak points in your isolation. Not only will they make noises in your room, they are spots where sound will leave your room. Sure you have a lot of surface density with a concrete room, but that doesn't matter if you have large holes in those walls where thin plastic is the only material between your sound and that hole! That's why you NEED to box it in. To figure out how much surface density you need, you can use the MSM calculator on the design forum or figure it out by hand using either the mass law equation or the two leaf MSM equation.However I do not really mind the sound that can be generated from the water pipes too much (leaking sound when it is raining, for instance). Would it be sufficient to ignore the pipes and just cover that gap with insulation? I mean if I find a reliable way to box them in in order to avoid the sound that would be great, but that is another big problem on it's own. I am not exactly sure how to find that "correct surface density" for the material to box them in.
Insulation by itself provides next to no isolation. Insulation does several things to improve isolation when used in conjunction with high surface density sheathing. You need mass to achieve isolation.Would it be sufficient to ignore the pipes and just cover that gap with insulation?
The smallest gap is what matters. So I would calculate the distance from the face of the wall, not the deep cavities.How would this wall fit in to the MAM model, knowing that right behind it there is a very thick concrete wall that hopefully we could take advantage of? Since the wall has a lot of holes (air), could we consider it as the air portion of the MAM? Will filling the holes with insulation help at all?
Yes, you have a lot of mass since it's concrete. However, your isolation is 100% determined by mass law. If you knew the exact thickness of the concrete, you could punch the figures into the mass law equation and see how it performs.Since the ceiling is very thick concrete, do you think the decoupled ceiling will be a good tradeoff for insulation vs. height? I'm thinking sound won't be able to escape very well through that thick concrete ceiling, but I'm just speculating. Still need a lot of reading up.
Wait until you are ready for treatment.Should I do REW measurements now? Or should that wait until we are working on the acoustic treatment?
Agreed.There is just not enough height to consider sound isolation AND treatment over head.
Also agreed. Hopefully you have enough isolation with the concrete alone. You WILL need to box in the pipes with VERY heavy material in order to maintain the isolation the concrete is providing. The same goes for the hole in the wall and any doors in the room! GregSo let us find out how much sound travels up through that concrete floor.
Aaaah, Drums. The sound of a drum kit is such a peculiar thing. For a start the drummer and audient hear vastly different sounds. The tone is very very room and position in room dependent. Big is generally best, and often very little or no treatment.
But KD Lang records drums in a closet to great effect.
The low ceiling causes problems with overhead mics. Very early reflections, comb filtering etc. etc.
Also cymbals sway about which can result in odd 'phasing' effects.
If your room proves viable in terms of isolation, there are ways to deal with the microphone issues.
e.g. PZM Microphones on the wall behind the drummer or to the sides, can replace the traditional overhead placement.
A decent Cloud over the drums should stop flutter echo and those early reflections bouncing into the OH mics.
Drums love a corner, which will boost their fundamental tone. Be aware that Kick drums can sound very very different pointing in different directions.
A great drum room would have high modal density. Lots of tonal support.
DD
Hey guys!
Quick update on the situation. Haven't been able to get my hand on powerful speakers to test the sound penetration in the basement, but I've got some studio monitors that I can borrow. Probably not ideal, but it's something for a first iteration and rough estimate on what we'll be dealing with. Also going to buy a hygrometer to get a feel for the humidity levels down there too.
Hoping to have some data to share soon.
PS: Also picked up Rod Gervais' Studio Construction book. Gotta get educated too if we're going to do this right!
Cheers!
If they can put out somewhere around 115 dBC, and they have reasonably good bass extension (to about 35 Hz or so), then that should work fine.but I've got some studio monitors that I can borrow. Probably not ideal, but it's something for a first iteration
Also get "Master Handbook of Acoustics" by F. Alton Everest. Very useful. - Stuart -PS: Also picked up Rod Gervais' Studio Construction book. Gotta get educated too if we're going to do this right!
Well that's bad news then ): The monitors I have are rated for a max of 97dB and down to 80Hz I believe. Guess it would still be worth to take some figures with this, but I'll definitely retake the test a week from now with the real drumkit.If they can put out somewhere around 115 dBC, and they have reasonably good bass extension (to about 35 Hz or so), then that should work fine.
Will do, thanks for the tip! Quick update, did a humidity test and looks like we're in the clear. 1 days worth of data shows a consistent reading of about 56% humidity. Quite surprised by that actually, thought the wine cellar would be more humid. Will keep gathering data for the sake of it. Also read that the general consensus regarding humidity and wooden instruments is that as long as there's no frequent and extreme changes, the instrument shouldn't suffer. For instance, having a consistent 70% humidity level will be better than swings from 40-60%. Don't quote me on that though, I don't have actual research to back this up, just general opinion online.Also get "Master Handbook of Acoustics" by F. Alton Everest. Very useful.
Hey everyone,
I'm back with an update, and data!
So I couldn't get my hands on some decent speakers as I stated in the last post. I decided to just wait for my drums to arrive and do the test with the real thing. I did some recordings in 10 different locations of my house, including outdoors. I took baseline measurements to get a feel of the noise levels without the drumming, and then took some measurements while I was drumming. The measurements are taken with the NIOSH app recommended in this same thread, and the samples are 1 minute long.
Unfortunately, (I noticed AFTER the samples were taken), the Z-weighted frequency option only applies to instantaneous levels, so this isn't reflected in the values I have taken. I can take these values and post them here without a problem though.
The measurements that the app took are: LAeq, Max level, and LCpeak. I have ordered the different places based on their distance from the studio, from closest to farthest away. Without further ado, here are the charts.
In case the baseline values look a bit high in the basement: I had a 3D printer turned on at the moment, so this is obviously reflected. However, I consider that to be pretty normal environment noise, so no harm no foul I guess.
So, I come to you guys. Does the studio room stand a chance in terms of noise attenuation? Looking forward to some conversation on this!
Thanks!
A small PA system might deliver the SPL of a Kit. No need for stereo, but you might need two subs to get there.
Thanks for the heads up about that SLM app. I need LZeq for a lot of my work.
SoundMeter by Faber is probably worth the money. I use it all the time, including 1/3 Octave Leq
As well as F and S there is an I time constant to deal with Impulsive sounds.
Drums are loud, and solo, can be very annoying. You could get a friend to play them and you go listen in your neighbours house.
Again, Aerodrums are brilliant IMO. Don't be fooled by their unsubstantial appearance. I would record an album with them.
DD
No need for that anymore. Got the real kit in there now so we can take accurate measurements.A small PA system might deliver the SPL of a Kit. No need for stereo, but you might need two subs to get there.
I believe you're the one that recommended it to me, so thank you!Thanks for the heads up about that SLM app. I need LZeq for a lot of my work.
Although this could be a solution to producers or other music makers, it definitely is not a valid for a drummer that wants to play on a real kit :wink: Thanks for your input Dan! Anyways, I've just read through Gervais' book on studio construction, and think it's about time to backtrack to the chapters dealing with the walls, especially to deal with the pipes and hole issue. I have a quick preliminary question though. I see gypsum boards (drywall) recommended a lot. Is there any difference in regards to sound isolation between using drywall and a wood product for walls, say MDF or what have you, if we consider them to have the same density and price point?Again, Aerodrums are brilliant IMO. Don't be fooled by their unsubstantial appearance. I would record an album with them.
In the MSM equation, there are 2 variables. Mass and Spring. The sheathing we use is the mass. Surface density is what matters here. Whether you use lead or glass or wood or drywall, it doesn't matter. Drywall is recommended all the time because it is fairly easy to work with, it's cheap, and it looks great when painted. It has downsides though. It has next to no structural integrity. Often is is recommended to use a layer of OSB behind your drywall so that you can easily mount treatment devices anywhere without having to find a wall stud. OSB is substantially more expensive than drywall where I live. GregIs there any difference in regards to sound isolation between using drywall and a wood product for walls, say MDF or what have you, if we consider them to have the same density and price point?
Got it, that's good to know. This is fairly in line with the little knowledge I've obtained from researching into this topic.In the MSM equation, there are 2 variables. Mass and Spring. The sheathing we use is the mass. Surface density is what matters here. Whether you use lead or glass or wood or drywall, it doesn't matter. Drywall is recommended all the time because it is fairly easy to work with, it's cheap, and it looks great when painted.
Also makes sense! I'll have to compare prices around here to see how I can work around the structural integrity of the drywall. I think I'm not going to be going to deep into wall construction yet though. A little update and a short-term plan for now: 1. Definitely the first thing to do will be to seal that giant, perfectly square hole in the wall (hole_in_wall_.jpg in the first post). I'm thinking of just brick and mortar to cover it up, and then maybe apply a thin layer of cement on top of that so the brick isn't visible. I'll do some tests when I have the brick and mortar set in, as the cement layer might not even be a good idea (a thin layer might not add too much mass comparatively to the rest of the wall). What do you guys think? Also, I think it will be very interesting to procedurally repeat the SLM tests I took as we add to the studio, in order to see how the changes improve one at a time. 2. After the hole in the wall, the next step is to address the water pipes. I need a little bit of guidance on this matter. Does it make sense to wall the pipes in a 2-leaf walls system, following MAM principles, knowing that later when I build the inner shell of the room these pipes will be between the two leaves of the room studio? It's kind of hard to explain, but if we take a look at the image studio_layout_top_down_constraints.png from the first post, it's easier to visualize. The water pipes are in the yellow section of the studio, and this yellow section, at least in my mind, is a good candidate for being the airspace between the external concrete walls and the internal studio shell/walls, which is it's own 2-leaf MAM system. So, we will have a MAM within a MAM, which will create, at best, a 3rd leaf if the external leaf of the water pipe is the concrete wall, and a 4th leaf if it is not. Both of these situations are undesirable as they decrease the overall absorption levels of the studio. So does anybody have any advice on how to approach the water pipe situation? I can make a Sketchup model of this to clarify if needed. 3. I'm starting to dive deeper into the HVAC matter. This topic is greatly explained in Gervais' book, and now I'm just looking into what system I should go after. Ideally, to avoid complicating the build with duct work which I have absolutely no experience in, I'd like to go for a mini-split system. Problem here is, of course, not all are designed for bringing fresh air into the room. I did run into this model (Daikin Ururu Sarara) from another post in the forum. It claims it can fill a 26m^2 room in 2h. This is a bit sketchy to me because... well, how can you claim to fill a 26m^2 room when that is a measure of area and with air and other fluids we are concerned about filling a volume? To be fair, I haven't gotten around to reading its specs. Also its pricepoint is kind of steep at 1500 euros... Anyways, the thing is there might be new mini-split or other systems nowadays that provide easy access to fresh air and I would really appreciate you guys' input on that. 4. Regarding the ceiling of the studio, I have more info. Although I haven't been able to obtain how thick the concrete is, it must be thick enough to support the weight of a car. I hadn't mentioned this before, but the roof of the studio is actually the floor of the garage right above! So this must mean it has to be at least somewhat thick. Also, I went ahead and took some more SLM measurements to see what we're dealing with. The new measurements are: Studio baseline levels (same as before, just for reference): 31.7 LAeq, 68.7 LCpeak, 47.5 Max level Garage baseline levels: 32.7 LAeq, 62.1 LCpeak, 42.4 Max level Studio levels while drumming (same as before, just for reference): 102.2 LAeq, 127 LCpeak, 108.8 Max level Garage levels while drumming: 59.8 LAeq, 84.5 LCpeak, 65.8 Max level Garage levels while drumming near the water pipes (pipes in the studio lead to garage): 61.1 LAeq, 87.6 LCpeak, 68.1 Max level The updated graphs are here: I know the measurements are not 100% accurate, especially them being taken from an iPhone app... but does it make sense to say that our concrete studio ceiling is giving us 102.2dB - 59.8dB approx 40dB of attenuation? That seems a bit high, but I'll take it if it's true! Having these values, does it make sense to put in an inner ceiling in the studio to decouple the structure from the concrete ceiling? If we manage to do that properly, how much of an increase can we expect to obtain keeping in mind our space restriction (1.95m height)? 5. Lastly, I'm a bit confused as to how to leverage the MSM equation -->Often is is recommended to use a layer of OSB behind your drywall so that you can easily mount treatment devices anywhere without having to find a wall stud.
According to the formulas that Gervais' presents, a doubling in the mass of the walls represents an increase of 6dB in STC (if I understood this, the sound will be "half as loud"). So my question is, in my current context, a doubling of the mass implies the mass present in both leaves? Or overall? Am I supposed to have an inner, drywall/wood leaf of the same mass as the concrete wall (impossible, I know) so I can get an extra 6dB reduction? What if I can't calculate the weight of the concrete walls? How can I know the STC increase? Does the weight discrepancy between inner and outer leaves matter? How does airspace fit into this? ... Sorry for all the questions. I guess I just need a kick in the right direction here on how thick / dense these walls should be. As a closing statement, I think I'm going to redo the baseline values I took in the basement. Like I said in a previous post, I had a 3d printer do some work in the background and this was affecting the readings. Will update with new charts once I get those new values. Apologies for the huge read everyone, but thank you all so much for the input!In the MSM equation, there are 2 variables. Mass and Spring. The sheathing we use is the mass. Surface density is what matters here.
Very, very few of them do that, and NONE of them do so at a rate that makes sense, or is even legal (in the sense that it meets code)... Not to mention that the very, very few mini-splits that do bring in fresh air, do NOT also ventilate the stale air! :roll: In a typical house or office, that isn't too much of a problem, since those are very "leaky" rooms, with lots of gaps, cracks, and holes for the air to escape through. But with a studio, there are zero holes, zero gaps, and zero cracks... the studio must be completely air-tight in order to isolate.... so where is the stale air supposed to go? You can't pump air into a room and not also have a path for the excess air to get out again... Short summary: there's no way of avoiding having ducts in your studio.Ideally, to avoid complicating the build with duct work which I have absolutely no experience in, I'd like to go for a mini-split system. Problem here is, of course, not all are designed for bringing fresh air into the room.
Exactly! Beware of HVAC specs that only mention floor area, without considering anything else. Not to mention that the ASHRAE specs, and therefore most building codes, specify that studios need at least six full room changes per hour, not one change every two hours! So that unit falls short by a factor of 1200%... :shock: Assume that the hypothetical 26m2 room has the height of a typical house room, at 2.4m: That implies a room volume of about 62m3. The unit in question takes two hours to change that much air, so it therefore can move air at the rate of 31m3 per hour. What you would actually need, according to ASHRAE, building code, and plain old common sense, is 372 m3 per hour (six changes per hour....). So you need 372, and this unit gives you 31... Hmmm: You are totally right... it does seem to fall a little short! :) Then there's the issue of speed... If it takes two hours to move all the air through the room, then that means that any buildup of CO2, stale air, or bad odors, will take at least 2 hours to clear.... Do you really want to be stuck with the smell of the drummer who hasn't showered in a month, or the guitarist who ate garlic bread for lunch, or the singer with a bowel problem.... even two hours after they already left, and the next band arrived? On the other hand, if you go with the correct ventilation rate, all of that nasty stuff will be gone in six minutes, not two hours.... To be fair, some fresh air is better than no fresh air, but the tiny little bit that comes in through such units is way, way short of what you need.It claims it can fill a 26m^2 room in 2h. This is a bit sketchy to me because... well, how can you claim to fill a 26m^2 room when that is a measure of area and with air and other fluids we are concerned about filling a volume?
Simple answer: Nope! No such thing exists. If it DID exist, it would need normal large diameter air ducts, many inches in diameter, in order to provide the right amount of fresh air. Sorry. There's no short-cuts here...Anyways, the thing is there might be new mini-split or other systems nowadays that provide easy access to fresh air and I would really appreciate you guys' input on that.
Yup! Considering that a typical drum kit played normally produces around 115 dBC, and you are only showing around 100, I'd say that it is WAY off! :) You also show a peak of 127 dBC, which is equally unlikely.... Unless maybe you took the measurement INSIDE the kick drum!.... To be honest, I doubt that the tiny little voice-oriented mic on an iPhone would be able to measure 127 dB... It is design to capture typical spoken word frequencies, at typical speaking SPL levels, from a distance of a few inches, not massively deep pounding very low frequencies, at very high SPL levels, such as kicks and toms... way lower and way louder than any human voice can go. So I'd take those numbers with a pinch of salt. When you can, beg, borrow or buy a real hand-held sound level meter, and use that to repeat your measurements. Maybe your meter really is accurate.... but maybe it isn't, and the only way to find out is to check it against one that IS accurate, measuring the exact same thing at the exact same time. [quote...]approx 40dB of attenuation? That seems a bit high, but I'll take it if it's true! [/quote]It's possible for a thick reinforced concrete slab, capable of carrying the weight of cars..... However! You have CARS driving over your studio? :shock: Ummm.... I would expect some rather deep low-frequency rumbling from that ceiling, from engines idling and heavy weights rolling across it... not to mention doors slamming, radios playing, and just plain old footsteps. Lots of impact noise going on there.I know the measurements are not 100% accurate, especially them being taken from an iPhone app...
Yes, definitely. Given that you have cars driving over your studio... see above.Having these values, does it make sense to put in an inner ceiling in the studio to decouple the structure from the concrete ceiling?
195??? :shock: Wow! You are going to loose at least 10cm of acoustic height (assuming that you do your ceiling inside-out, which is basically the only option here) plus whatever is needed for the framing, which will set your visual ceiling height. Assuming that you can get by with only 2x6 joists, that implies losing another 15cm (If you need 2x8 joists, then it would be 20cm). So allow for losing 25 to 30 cm, meaning your final visual ceiling height will be around 170 or as low as 165. This does not seem viable to me, unless you and your musicians are not very tall. Even if you skimp on isolation, and use very high density materials for your mass, your final visible ceiling height is never going to be more than about 175cm. Even if you don't install any isolation at all, and simply treat the existing concrete roof with suitable acoustic treatment, your visual ceiling height is still not going to be more than 180cm...If we manage to do that properly, how much of an increase can we expect to obtain keeping in mind our space restriction (1.95m height)?
Forget STC. It's not a valid method for measuring studio isolation. Here's why: STC was never meant to measure such things. Here's an excerpt from the actual ASTM test procedure (E413) that explains the use of STC. “These single-number ratings correlate in a general way with subjective impressions of sound transmission for speech, radio, television and similar sources of noise in offices and buildings. This classification method is not appropriate for sound sources with spectra significantly different from those sources listed above. Such sources include machinery, industrial processes, bowling alleys, power transformers, musical instruments, many music systems and transportation noises such as motor vehicles, aircraft and trains. For these sources, accurate assessment of sound transmission requires a detailed analysis in frequency bands.” It's a common misconception that you can use STC ratings to decide if a particular ceiling, wall, window, door, or building material will be of any use in a studio. As you can see above, in the statement from the people who designed the STC rating system and the method for calculating it, STC is simply not applicable. Here's how it works: To determine the STC rating for a ceiling, wall, door, window, or whatever, you start by measuring the actual transmission loss at 16 specific frequency bands between 125 Hz and 4kHz. You do not measure anything above or below that range, and you do not measure anything in between those 16 points. Just those 16 small bands, and nothing else. Then you plot those 16 points on a graph, and do some fudging and nudging with the numbers and the curve, until it fits in below one of the standard STC curves. Then you read off the number of that specific curve, and that number is your STC rating. That's it. There is no true relationship to real-world decibels: it is just the index number of the reference curve that is closest to your curve. To clarify: the STC number is NOT how much isolation you will get in a studio: it is just the number that somebody once assigned to a curve on a graph. So for the STC-70 curve, they could have called it "STC-GGFQRT" or "STC-Delta-RED" or "STC-Elephant-seven" or anything else, and it would tell you just as much about isolation as "STC-70" does: ie, nothing. It's a REFERENCE number, not an actual isolation number. For speech conditions, yes, STC-70 might actually be close to 70 dB of isolation, but not for music. When you measure the isolation of a studio ceiling, wall, door, etc., you want to be sure that it is isolating ALL frequencies, across the entire spectrum from 20 Hz up to 20,000 Hz, not just 16 specific points that somebody chose 50 years ago, because he thought they were a good representation of human speech. STC does not take into account the bottom two and a half octaves of the musical spectrum (nothing below 125Hz), nor does it take into account the top two and a quarter octaves (nothing above 4k). Of the ten octaves that our hearing range covers, STC ignores five of them (or nearly five). So STC tells you nothing useful about how well a wall, door or window will work in a studio. The ONLY way to determine that, is by look at the Transmission Loss curve for it, or by estimating with a sound level meter set to "C" weighting (or even "Z"), and slow response, then measuring the levels on each side. That will give you a true indication of the number of decibels that the wall/door/window is blocking, across the full audible range. Consider this: It is quite possible to have a door rated at STC-30 that does not provide even 20 decibels of actual isolation, and I can build you a wall rated at STC-20 that provides much better than 30 dB of isolation. There simply is no direct relationship between STC rating and the ability of a barrier to stop full-spectrum sound, such as music. STC was never designed for that, and cannot be used for that. It was meant for describing isolation of speech, not music. It's reasonably useful for what it was designed for, but not very useful for music. Then there's the issue of installation. You can buy a door that really does provide 40 dB of isolation, but unless you install it correctly, it will not provide that level! If you install it in a wall that provides only 20 dB, then the total isolation of that "wall+door" combination is about 20 dB: isolation is only as good as the worst part. Even if you put a door rated at 90 dB in that wall, it would STILL only give you 20 dB. The total is only as good as the weakest part of the system. So forget STC as a useful indicator, and just use the actual TL graphs to judge if a wall, door, window, floor, roof, or whatever will meet your needs.a doubling in the mass of the walls represents an increase of 6dB in STC
Not really, no. You need a change of 10 dB to judge that a sound is half as loud (or twice as loud). 6 dB is not a big change.(if I understood this, the sound will be "half as loud").
Great! But it would be best to do those with a proper meter, not an app on an iPhone. Apps are fine for getting a rough idea of typical situations, but they can't handle extremes. And to start with, the mic on an iPhone is not omnidirectional... real acoustic measurement mics are: they have to be. But phone mics are specifically designed to be very directional, and even to cancel out noise coming from other directions.... Food for thought... - Stuart -As a closing statement, I think I'm going to redo the baseline values I took in the basement.
This actually makes a lot of sense the way you put it. Of course, we can't NOT have ducts and expect stale air to go out and fresh air to go in. I need to do some more thinking regarding this area then, because I cannot seal the hole in the wall knowing that it might actually come in handy for the duct work. Regarding this, I saw some posts where people have had luck using another room adjacent to the studio as a "fresh air chamber". They'll pull the air in through ducts and ventilators from that room which already has AC installed. This seems like it would be the simplest solution in my case, since I have two adjacent rooms to my studio, and both with windows, and also one of those rooms I can reach via the gaping hole in my wall! I guess I could go for something like this mentioned in Gervais' book: I'll have to do some calculations to see how much air I'll actually need in order to get equipment that best fits the job, but I'm open to any pointers anybody has regarding this.Very, very few of them do that, and NONE of them do so at a rate that makes sense, or is even legal (in the sense that it meets code)... Not to mention that the very, very few mini-splits that do bring in fresh air, do NOT also ventilate the stale air! :roll: In a typical house or office, that isn't too much of a problem, since those are very "leaky" rooms, with lots of gaps, cracks, and holes for the air to escape through. But with a studio, there are zero holes, zero gaps, and zero cracks... the studio must be completely air-tight in order to isolate.... so where is the stale air supposed to go? You can't pump air into a room and not also have a path for the excess air to get out again... Short summary: there's no way of avoiding having ducts in your studio.
The good thing is, for the time being I'll be the only drummer who hasn't showered playing in my room! :lol:If it takes two hours to move all the air through the room, then that means that any buildup of CO2, stale air, or bad odors, will take at least 2 hours to clear.... Do you really want to be stuck with the smell of the drummer who hasn't showered in a month, or the guitarist who ate garlic bread for lunch, or the singer with a bowel problem.... even two hours after they already left, and the next band arrived? On the other hand, if you go with the correct ventilation rate, all of that nasty stuff will be gone in six minutes, not two hours....
Yeah, I totally agree. It would definitely be a good idea to shell out some money on a proper mic for testing, but at least we have some very rough values we can use as guidance for now.So I'd take those numbers with a pinch of salt. When you can, beg, borrow or buy a real hand-held sound level meter, and use that to repeat your measurements. Maybe your meter really is accurate.... but maybe it isn't, and the only way to find out is to check it against one that IS accurate, measuring the exact same thing at the exact same time.
I think I might not have fully explained myself! The garage is my own, 1-car garage that's sitting on top of the studio area. There will be absolutely no issue of noise from cars driving above as it will only ever be my car parked there :D With this in mind, taking height limitations into account, and knowing there will be no noise from cars coming from the ceiling, does it still make sense to have the decoupled inner ceiling?You have CARS driving over your studio? :shock: Ummm.... I would expect some rather deep low-frequency rumbling from that ceiling, from engines idling and heavy weights rolling across it... not to mention doors slamming, radios playing, and just plain old footsteps. Lots of impact noise going on there.
Unfortunately, we are working with a very small ceiling height... Which is why I'd like to minimize losing headspace in the studio and leverage the powers of our concrete slab ceiling! Ok but on a more serious note, I have no issue at all putting in place an interior ceiling, I just want to make sure it's absolutely worth it and we can make something that truly works with the ceiling already in place. As long as I can get 175cm height in the room after treatment is in place, I'll be fine. In this case, how much airspace should there be between external concrete ceiling and the internal ceiling we are to build?195??? :shock: Wow! You are going to loose at least 10cm of acoustic height (assuming that you do your ceiling inside-out, which is basically the only option here) plus whatever is needed for the framing, which will set your visual ceiling height. Assuming that you can get by with only 2x6 joists, that implies losing another 15cm (If you need 2x8 joists, then it would be 20cm). So allow for losing 25 to 30 cm, meaning your final visual ceiling height will be around 170 or as low as 165. This does not seem viable to me, unless you and your musicians are not very tall. Even if you skimp on isolation, and use very high density materials for your mass, your final visible ceiling height is never going to be more than about 175cm. Even if you don't install any isolation at all, and simply treat the existing concrete roof with suitable acoustic treatment, your visual ceiling height is still not going to be more than 180cm...
Explained beautifully, Stuart. Thank you :) Stuart, do you think my plan of action going forward makes sense? 1. Design HVAC system with priority on getting fresh air in and stale air out 2. Fill gaping hole in the wall 3. Start diving into the specifics of the inner assembly: wall thickness, material, airspace and distance away from exterior walls, insulation 4. Electrics shouldn't be a problem here, I've got good access in the studio. Would love some more pointers! Thank you all!Forget STC. It's not a valid method for measuring studio isolation. Here's why: STC was never meant to measure such things. Here's an excerpt from the actual ASTM test procedure (E413) that explains the use of STC.
Right! so first figure out what your needs are in terms of how much air volume you need to move, and what the velocity of that air will be inside the ducts: that allows you to calculate the size of ducts that you will need, and the size of the of the silencer boxes. The "silencer boxes" are the "thingies" (very technical term that! :) ) which you need to use to allow the air to go through the wall but block the sound. Think of it this way: the duct is basically just a huge, enormous, gaping hole in your wall. If you just put in a typical flex duct, or thin sheet metal duct, the sound will go right through that hole and out the other side, practically attenuated. And vice-versa: sound outside will get in through that hole. In other words, the simple act of installing HVAC ducts totally trashes your isolation. The solution is "silencer boxes". Sometimes also called "baffle boxes". Each one is just a large wooden box with a few baffles inside, and lined on the inside with "duct liner". The air can flow around the baffles easily, but the sound cannot. Here's a few examples that forum members have built: viewtopic.php?f=2&t=15430&start=45 viewtopic.php?f=2&t=1929&start=74 viewtopic.php?f=1&t=11542&start=5 viewtopic.php?f=2&t=9761&start=0 viewtopic.php?f=2&t=11485&start=98 viewtopic.php?f=2&t=11508&start=157 viewtopic.php?f=2&t=13821 viewtopic.php?f=1&t=15378&start=44 viewtopic.php?f=2&t=18202&start=16 Not all of those are good designs, but you get the idea. You need one such box at ever pint where a duct goes through a wall "leaf".I need to do some more thinking regarding this area then, because I cannot seal the hole in the wall knowing that it might actually come in handy for the duct work.
That's the "exchange chamber" concept, and you can do that if you want.... but the "other room" cannot be a habitable space: most building codes do not allow you to dump stale air from one habitable space into another. You can only do that if the "other room" will not be used by people (or pets). Also, the "exchange chamber" does not negate the need for silencer boxes, ducts, or the mini-split itself. You still need all of those. It's only really useful if you have a very noise mini-split and don't want it in the studio with you. In which case, you bought the wrong mini-split! :) You can accomplish the same result by using a ducted mini-split located outside of your studio, instead of a non-ducted ("unducted" or "ductless") unit inside the room. Here's what the two different types look like: The one on the left is the typical non-ducted unit that you see in homes, shops and offices all over the place. The one on the right is a similar "ducted" model. It's basically the same thing as the one on the left, without the pretty plastic casing around it, and with duct flanges attached on each side. That's it. They both do the same job. So, instead of having a ductless unit inside your room plus separate ducts for supplying the fresh air circulation, you can combine both systems into one by installing a ducted unit in one of your "extra" rooms. You simply run the supply and return ducts through the wall and hook them up to the ducted unit, which then circulates the air through the room while also treating it (cooling / heating / dehumidifying ). You then add a much smaller extension duct to dump a small percentage of the return air to the outside world, and another similar small duct to bring in fresh air from the outside world. Done! In other words, the unit itself circulates the required "six room changes per hour" through the room, while also adding in some amount of fresh air to that, and dumping the same amount of stale air. Usually, you want to have about 20-40% of your recirculating air replaced by fresh air, to keep things happy and healthy. Figure roughly 30% initially, then refine that if need by. And that's it! It's not a complicated solution, and it works very well. That's the way I do most studios these days.Regarding this, I saw some posts where people have had luck using another room adjacent to the studio as a "fresh air chamber".
Calculate the total volume of air in your room (length times width times height). Multiply that by 6 (because you want six room changes per hour). That tells you how much air you need to move per hour. Must fans and HVAC systems specify the air flow rate in cubic feet (or cubic meters) per minute, not per hour, so you need to divide by 60 to get that. Some metric systems specify in "liters per minute" or "liter per hour", so you'd need to do the relevant conversion there. But the basic concept is that you need to replace the entire air volume of your room, six times per hour at least. Better is eight times per hour, or more, but at least six.I'll have to do some calculations to see how much air I'll actually need in order to get equipment that best fits the job, but I'm open to any pointers anybody has regarding this.
Don't get confused here! An acoustic measurement mic is one thing, but a sound level meter is another! You might need both.... The sound level meter is a calibrated device that should give you an accurate reading of how loud things are. The acoustic measurement mic is for testing the actual acoustic response of the room, using something like REW to do that.Yeah, I totally agree. It would definitely be a good idea to shell out some money on a proper mic for testing,
There are no other similar garages on either side of yours? Yours is the one and only parking spot in the building?I think I might not have fully explained myself! The garage is my own, 1-car garage that's sitting on top of the studio area. There will be absolutely no issue of noise from cars driving above as it will only ever be my car parked there
If you are certain that there won't be any structure-borne impact or flanking noise in that slab above you, then you might be OK. But if that slab extends beyond just your parking garage to other places where there might be noisy things happening, then it would be wise to isolate. However, if you have structure-borne noise in your ceiling, then it is also in your walls... You might need to isolate your walls too.With this in mind, taking height limitations into account, and knowing there will be no noise from cars coming from the ceiling, does it still make sense to have the decoupled inner ceiling?
This all a "juggling game", where there are many parameters to take into account, but basically you have to tune the resonant frequency of that ceiling to be at least one octave below the lowest tone that you need to isolate. That's what the MSM equation is all about: it teaches you how to juggle. The resonant frequency depends on basically two factors: the mass of each leaf, and the distance between them. If you have very high mass on both, then you can get away with less distance and still get the same result. Conversely, if you have plenty of space, then you can get way with less mass. In your case, you do have good mass on one leaf (the existing concrete slab), so you might be able to get away with less gap. The normal recommendation is a minimum gap of 4" (10cm). That's the distance across the cavity from the surface of the outer leaf mass to the surface of the inner leaf mass. The location of the supporting framing for your inner-leaf mass is irrelevant here: the joists could go inside the cavity (above the drywall), or they could go inside the room (below the drywall). If you need a thinner cavity, then you probably do need to get the joists out of it, as they take up a lot of space, so building your ceiling "inside out" would be the best option. If you use something that has a much higher density than drywall (eg, fiber-cement board), then you can save another few mm of height. In other words, you need to do some math here, to figure this out. But count on a gap of at least 2" (5cm): I can't see it being possible go with less than that. And fill that cavity with suitable insulation, of course! So, assuming 7cm of air gap, and 3cm of sheathing (drywall/fiber-cement/MDF/etc), you have 10cm for the actual isolation part. Then below that you need some type of framing to support it. The dimensions of that framing lumber depends on the total weight that you need to support (the isolation stuff, plus the framing itself, plus the insulation, plus any treatment that will be hung from the ceiling, plus lights, wiring, etc.), and the distance that they have to span. That is likely to be at least 2x6 joists, which measure 14cm deep. Thus, the total lost height is 14cm + 10 cm = 24 cm. If the distance to be spanned is short enough, and / or the weight is low enough, you MIGHT be able to get away with 2x4 joists spaced closer together (eg, 12" OC, instead of 16" OC), which would be great because those are only 9cm deep. So you would lose just 9cm + 10cm = 19cm in that case. I can't see it being possible to get less than that, though. - Stuart -In this case, how much airspace should there be between external concrete ceiling and the internal ceiling we are to build?
That should be straight forward enough. So I decided to do the math taking into account the external walls of the studio and not the inner shell itself. The difference isn't that big anyways, but when talking about air I guess it's better to overestimate than underestimate. This puts us at 40.04m^3. Taking into account we want 6 room changes per hour, we're looking to move 240.24m^3 of air per hour. Now, from what I've gathered, lower velocity air in the ducts should be quieter, correct? In fact this is why we can compensate the slower speeds with larger ducts because we can move the same amount of air at a lower velocity and thus less noise. Anyways, putting that as an aside, I still have to take a look at HVAC systems specs because I'm not exactly where the "speed" comes from in this system. Does the speed of the air depend on the ventilator unit placed outdoors? Do I have to put fans inside the vents? I'd appreciate some pointers here and if you know of any good brands of system, I'd be more than glad to hear it.Right! so first figure out what your needs are in terms of how much air volume you need to move, and what the velocity of that air will be inside the ducts: that allows you to calculate the size of ducts that you will need, and the size of the of the silencer boxes.
Got it. I have a feeling we'll be making a couple of these baffle boxes then. Not a problem!You need one such box at ever pint where a duct goes through a wall "leaf".
I'm hoping the specs regarding DB's on these units are easily provided by manufacturers! I think it's about time to go HVAC hunting....if you have a very noise mini-split and don't want it in the studio with you. In which case, you bought the wrong mini-split!
Thank you for that. I love working with concrete numbers, makes everything much less of a guessing game! Given your explanation, I think I will take a look at ducted mini-split systems and see if I can find something that suits my room requirements.Usually, you want to have about 20-40% of your recirculating air replaced by fresh air, to keep things happy and healthy. Figure roughly 30% initially, then refine that if need by.
Aah got it. Didn't know that. I think for sure the acoustic measurement mic will come in handy. Even though we know it's a small room and we will have modal issues with lower frequencies, it will be best if we can have some accurate REW values to optimize the treatment.Don't get confused here! An acoustic measurement mic is one thing, but a sound level meter is another! You might need both.... The sound level meter is a calibrated device that should give you an accurate reading of how loud things are. The acoustic measurement mic is for testing the actual acoustic response of the room, using something like REW to do that.
Nope. The studio is in a house / townhouse kind of situation. My parking spot is situated in the only garage in my house, only fits my car, and will have virtually no movement while I am in the studio, not from myself or neighbors, so we are kind of lucky that this is the ceiling we have above the studio. The only inconvenience with the studio walls is that I share one wall (however, it is concrete) with my neighbor's basement. I think he has a gym in there, so I don't think he'll mind much :cop:There are no other similar garages on either side of yours? Yours is the one and only parking spot in the building?
I am not exactly sure if the concrete slab itself which supports the roof of my studio (and the floor of my garage) extends to my neighbor's house. To me, it doesn't make much sense for it to be a shared concrete slab, although I have no idea how these houses are built. Technically, the houses are side by side and touching each other, but other than the shared wall mentioned in the paragraph above, we shouldn't have too much of a problem with them. The neighbors aren't too noisy, and if anything the slab will support their living room floor and wouldn't even be directly on top of my studio. I don't have a problem at all isolating and decoupling the walls. In fact I was expecting to do so, more so to prevent noise in my studio from going to other places in my house and disturbing the people living here than anything else. Regarding the ceiling. I read your explanation and I appreciate the time you have taken to go into detail. It definitely looks like height will be an issue. However, I have a question that will probably have people call me lazy/crazy. Here goes: I get a slight feeling that doing all that work on the ceiling will be a lot of effort for slight reward. If we take a look at the measurements I have taken (I know, an iPhone app isn't very reliable but it's something!) We can see that from ~100dB in the studio while playing, directly above in the garage we observe around ~60dB. In my noob opinion, this isolation doesn't look that bad for having absolutely no treatment; it seems that the cement structure is pretty sturdy. Given this, does it make sense to leave the ceiling treatment as a last resort? So what I propose is, let's focus on the very weak points first, which there are plenty (hole in the wall and very thin doors) and then move on to making the decoupled walls. I'll do another sound test, and if everything is within acceptable levels, we can call it and maintain that precious ceiling space. Now, I know this has risks. If it turns out that after that treatment our weakest point is the ceiling and the sound attenuation is not enough, I know I will have to backtrack, modify the walls and possibly other things, and put the ceiling in place. What I want to avoid is losing ~15-20cm of ceiling space when we might end up with another weak point that will make all that lost space and effort basically useless. If we can make that concrete ceiling the weakest point in our assembly, I think that is some really good news! However, if this is a stupid idea as it may very well be, I will trash this and revisit the ceiling treatment. So, does this approach make any sense at all? Hope it's not asking for too much! Thank you all for your help!If you are certain that there won't be any structure-borne impact or flanking noise in that slab above you, then you might be OK. But if that slab extends beyond just your parking garage to other places where there might be noisy things happening, then it would be wise to isolate. However, if you have structure-borne noise in your ceiling, then it is also in your walls... You might need to isolate your walls too.
Acoustic treatment has next to no affect on isolation. Treatment and isolation are two completely different things.In my noob opinion, this isolation doesn't look that bad for having absolutely no treatment
Totally. You would have to build your inner leaf room after the outer leaf is completely sealed anyway. So yeah, complete your outer leaf and hopefully it is good enough isolation for your needs. GregSo what I propose is, let's focus on the very weak points first, which there are plenty (hole in the wall and very thin doors) and then move on to making the decoupled walls. I'll do another sound test, and if everything is within acceptable levels, we can call it and maintain that precious ceiling space.
I am aware of this. That was poor wording on my part, what I meant was that the isolation provided by the concrete slab ceiling by itself, without any further work on seems to do a pretty good job (approx 40dB reduction... disclaimer, measurements taken with iPhone app).Acoustic treatment has next to no affect on isolation. Treatment and isolation are two completely different things.
Sounds like a plan. Looks like I'll be doing the inner leaf without the decoupled ceiling then to save that space. That should be enough for my needs hopefully. Going to post a follow-up question in a couple of minutes. Drawing up the diagrams in the meanwhile.Totally. You would have to build your inner leaf room after the outer leaf is completely sealed anyway. So yeah, complete your outer leaf and hopefully it is good enough isolation for your needs.
Hello again!
Another question regarding the wall assembly, especially regarding the MAM model. Greg already mentioned something regarding this issue in the first couple of posts, but I'd like to dive a bit deeper.
The issue surrounds the existing wall used to hold wines that is present in the studio. I can't take this wall down. It is made of what seems to be some kind of red ceramic and full of holes (pictures in the first and second posts). I've taken more measurements. It measures 23.5cm deep and it's outer face is 7cm from the exterior concrete foundation wall. Diagram to clarify:
So, going over the basics. 3 Leaf systems are bad. 2 Leaf systems are much better. So the question is *what* to do with that wine wall. Should we treat that as our inner leaf? It's surface density can't be too good given that it is full of holes, and unfortunately I don't see any possible way of getting the insulation into the 7cm cavity behind it. Maybe we can reinforce this wine wall by putting another wall directly on its inner face, thus achieving the 2 leaf system and covering up the holes. However this still leaves us without a way of putting the insulation in the 7cm cavity.
Another way would be to go for the 3 leaf system. Put up an inner leaf parallel to the wine wall, enough airspace between the two to fill with insulation, and have that there, but of course this will probably not be as good as a well-designed 2 leaf system.
In this case, what's better, the 2 leaf system with no insulation? Or a 3 leaf system with proper insulation? Is there any other option I may be missing?
Thanks everyone for the help!
Update for those following this thread: just found a good deal on moisture resistant MDF. It's a 3cm thick board, with a density of about 730kg/m^3 which translates to roughly 21.9kg/m^2. This is based off values found on the internet for moisture resistant MDF; I'm still waiting on the supplier for the datasheet to get the actual numbers.
Pros of going moisture resistant MDF:
1. Well, it's moisture resistant and I'm in a basement surrounded by water pipes. Could prove useful.
2. It's very sturdy material at 3cm thickness. Walls will not be as easy to break and I can hang acoustic treatment on it without necessarily having to find a joist for support.
3. Since it's already 3cm thick, I will not have to stack sheets of drywall to achieve the same thickness
Cons:
1. More expensive than gypsum board
2. Could possibly be a bit more difficult to install than gypsum board
The price I'm getting on the MDF is 55 Euros per 244cmx122cmx3cm board, which comes to about 18 Euros per m^2. Having around 36 m^2 of walls to put up, the price of the inner layer comes out to be around 650 Euros. That's not too shabby at all!!
This seems like a great deal for the density and benefits I am getting over the drywall, even taking into account drywall might come out to around 300-500 for the room. If we put price aside, are there any blatant reasons why I should not put up the inner studio shell with this type of material?
Thanks!
That sounds like a pretty good deal!
Nope! No problem. It's high density, thick, strong, has a good nailing surface, reasonably priced, etc. Depending on what your isolation needs are, you could probably get by with just that as the base layer on your framing, then a single layer of 16mm drywall on top. Likely, that will be enough. By the way, I did answer your PM: Not sure if you saw that? - Stuart -If we put price aside, are there any blatant reasons why I should not put up the inner studio shell with this type of material?