Drum practise space: using an existing room

Hi, I've been recently directed to this site and have so far been overwhelmed with the amount of information available. Thanks! What an amazing resource. After reading through some information related to my situation I would now like to tell you exactly what I'm planning on doing and look forward to receiving any advice. I am located in Melbourne, Australia. My goals are to create a space where I can practise(drumkit and Balinese drum:kendang) at night(up until midnight) because I have a child that demands my attention during daylight hours. In future I would like to use the space for 1 on 1 teaching(drum lessons) and also for 2 musicians to rehearse together(jazz oriented music, not a rock band). I imagine that any rehearsals would be done during daytime. I am not a loud drummer(jazz oriented music with a slightly harder edge) but the Balinese drum is played with a stick on one side and the sound is quite bass heavy and boomy. (Sits on the lap as a double sided barrel drum) Neighbours are located quite close to the building: 1.5 meters away is the closest neighbours house. In terms of where I am in the process: The space is an already existing bungalow in the backyard, I've removed all the plasterboard from walls and ceiling and have removed the cladding from the exterior walls. From there I've just been researching: talking to musicians locally that have sound proofed their own spaces, have spoken with a professional studio designer. It seems there are so many different ways to do this and I'm fearful of of beginning and then it not being successful. Details of the room: The entire room is 5570mm in length, BUT, I will only be sound proofing half on this area. I have attached photos of my drawings of a floor plan and 3D model. -The room is on wooden stumps 350mm off the ground. -The roof is corrugated iron, easily removable. -The current flooring material is wooden floorboards. -As you will see on the 3D plan the roof/ceiling is angled(ie, not parallel with floor). -There is a window in the drum room space which will be removed but I have already sourced a double glazed window to take its place, same dimensions. -The distance between exterior and interior walls is 950mm(stud depth), the rafter(roof) depth is 1200mm,and floor studs 950mm deep. Other things to note: -My dad is a builder so the construction can be done by the two of us. Unfortunately he has no knowledge of acoustic treatment or sound proofing -I have an uncle who manages a plywood mill so am able to get sheets of ply(seconds, at any thickness up to 27mm) at no cost. -My budget is $1500 and could go to $2000 if needed.....am prepared to be told it's not possible with that....:) One of our concepts was to use 27mm plywood on all exterior walls including roof and floor, then insulating using acoustic batts in the walls, floor and ceiling, and then 12mm plywood on the interior walls. Then laying thick underlay and carpet and flooring material. That was a basic idea as it makes use of the plywood I have access to at no cost. I hope I've covered everything required and look forward to your input. Thanks, Adam

Hi Adam, and welcome! :) It would be good if you could measure the actual sound level of your drum playing. Get hold of a sound level meter, and put some real numbers to what you do. A drum kit played hard is in the region of 115 dB, and you say that you don't play that loud, but that still doesn't tell us of we are talking about 110 dB or 90 dB. That's a factor of one hundred times difference in sound power, so it's kind of important! In other words, we need to know how loud you are, in objective, real-world decibels, not subjective opinions. You also say you want to play at night, and that you have neighbors 1.5m away, so you need to answer the other question: How quiet do you have to be? Your local municipal noise ordinance will tell you that. Pay a visit to their web site, or in person, and get a copy of that. It will tell you what the maximum legal level is for noise at midnight, also in terms of decibels, and it will tell you how and where that level is to be measured. So, with those two numbers in hand, you can answer the REAL question: How much isolation do you need? Simply subtract your "How quiet" number from your "how loud" number, and you have your answer. With that number in hand, now you can look at the various possible types of construction that have been tested and are known to give you the right amount of isolation. You can look at those, and pick the one that best fits your existing structure, and your pocket.

It seems there are so many different ways to do this and I'm fearful of of beginning and then it not being successful.

Well, the approach I outlined above is the ONLY sane, logical, scientific way of doing it! Listening to how other people built thiers is not going to tell you how to build yours, since all studios and all situations .are different. For example, in your case you have three major issues: small children in your own house, neighbors breathing down your neck, and you want to play drums at midnight! So your isolation needs are very much higher than those of the guy who lives alone in the middle of an empty field, and only ever plays the harmonica at 10:00 AM! OK, so I exaggerate a little, but you get the point: doing what someone else did most likely is no good for you).

-The room is on wooden stumps 350mm off the ground.

That's the first bad news: It implies that your floor is not a concrete slab on the ground, so it's not going to be easy to isolate that. Got any photos of that part of your building? It would be good to see what you have, and see if there are any practical solutions for that.

-The roof is corrugated iron, easily removable.

Second bad news: corrugated iron doesn't have a lot of uses, acoustically! It's good that you can take it off, though. Replace it with something more substantial, massive and rigid.

-The current flooring material is wooden floorboards.

Good acoustically (makes the room sound nice) but probably not so good for isolation. You need to get lots of mass in your floor somehow.

-There is a window in the drum room space which will be removed but I have already sourced a double glazed window to take its place, same dimensions.

If you are talking about the typical double-glazed window that consists of two panes of glass in the same frame, separated by a thin air gap, then forget it. That's no use at all for what you need. That isolates typical house and office noises reasonably, but won't do much for drums! A thin air gap is no use for isolating low frequencies.

-The distance between exterior and interior walls is 950mm(stud depth),

950mm? As in 95 cm??? as in roughly 37 inches???? Those are SOME studs!!!! Maybe you meant 95mm? (a bit less than 4") :)

-I have an uncle who manages a plywood mill so am able to get sheets of ply(seconds, at any thickness up to 27mm) at no cost.

Oh MAN!!!! How can I get him to be my uncle too?!!! You lucky fellow! Free plywood, in any thickness you want.... Excuse me while I turn green with envy.... :) That's good news. You sure can use that in your build. First thing I'd suggest (after getting your numbers figured out) is to re-do your plans in SketchUp. It's free software, and very powerful, once you get the hang of it. First, do a model that shows the existing structure as it is right now. Then add what you plan to do, in a second copy of that model, and post them both for us to take a look at. And also post some photos of the existing structure! - Stuart -

Hi Stuart, Thanks very much for your response and suggestions. I'll get those numbers worked out and prepare my plans on SketchUp and post again soon. Oh, yes, I did mean 95mm studs....thanks :D ........you're right, 950mm is some serious studs...haha The double glazed window is the typical design(two panes of glass in same frame with an air gap).......I'm not precious about having a window but during the day, (when I can get away with projecting more sound through the neighbourhood), it might be nice to have some daylight coming in.......I've heard that you can create a window plug or cover if the window is a weak link.....would love to hear your thoughts on this..... Thanks again, Adam

The double glazed window is the typical design(two panes of glass in same frame with an air gap)...

No use for what you want! Forget that. That will work fine for speech, but NOT for drums. Let me explain: When you have two sheets of "something" separated by an air gap, you have a tuned system. Technically, it is called an "MSM" system, for "Mass-Spring-Mass". In the case of double glazing, the panes of glass are the "Mass" on each side, and the air trapped in the middle is the "Spring". That's a resonant system, and it will resonate whenever it "hears" the tone it is tuned to, or tones nearby. For those frequencies (around its own resonant frequency), it is transparent to sound: it lets the sound straight through as though it wasn't even there. At about 1.4 times the resonant frequency, it starts isolating. At twice the resonant frequency, it isolates reasonably, and at three times the resonant frequency and higher it isolates quite well. The "tuning" is set by the amount of mass on each side, and the thickness of the air gap. As the mass goes up, the frequency goes down, which is GOOD! You want the resonant frequency to be as low as possible, ideally no more than half of the lowest frequency that you want to isolate. And as the depth of the air gap increases, the frequency also goes down. So here's the problem: The type of typical double-glazing that you mention has thin glass (low mass) and a thin air gap. So guess what? It is tuned to a high frequency! Low enough that it still isolates speech and similar sounds quite well, but way too high to isolate drums. If you really want to play drums at midnight, then forget typical commercial double-glazing. You need a much larger air gap, and much more mass, to isolate drums. Studio windows for accomplishing that normally have air gaps upwards of 4 inches (10cm), and commonly 6 or even 8 inches (15 to 20 cm), while the air gap in a typical commercial double-glazed window is just a cm or two. Also, the glass used in commercial double glazing is just a few mm thick, while the glass used in studio windows for isolating drums is at least a cm think, and commonly much more. As you can see, isolating drums is not easy! It can be done, but not with commercial double glazing. You need heavier laminate glass, and you need deep air gap. How heavy and how deep are things that you'll get into as you advance with your design, and figure out how much isolation you need. There's a process here, a sequence of things to be done. There are equations you can use to calculate things, and stacks of research that you can refer to, to better understand what you can achieve and how to achieve it.

I've heard that you can create a window plug or cover if the window is a weak link.....

Yes, you can do that, but once again you have to design it to meet YOUR needs, to give you the level of isolation that YOU need. The plug that worked for the next guy might be totally inadequate for you, or it might be extreme overkill. In order to find out, you need to take those measurements with a sound level meter, and do the math on different options of plug, to see which one will do what you need. - Stuart -

Thanks again for the info. I'm working on getting those numbers, although the response I had from my local council was quite vague and very subjective. Apparently there's no decibel limit, it's just what your neighbour considers to be "reasonable", or "unreasonable". There are time limits though.... Once I've measured my playing with the meter I'll post the council reply with that. I'm slowly getting my head around SketchUp,....will hopefully post my design soon along with photos. In the meantime, I wanted to ask about ventilation. If the room is airtight, how do you get air in AND out without sound escaping? Thanks, Adam

Apparently there's no decibel limit, it's just what your neighbour considers to be "reasonable", or "unreasonable".

That's unusual! Most places have very well defined limits that depend on the time of day. With no actual numbers, how do they enforce the limits? That's like setting a speed limit to be "not too fast": How can the cops give you a ticket for driving 10 km/h beyond "not too fast"? Anyway, even if there's no legal limit, there's still going to be limits that you have to set. And if it isn't going out, then it will be coming in. Measure how loud things are around you (neibours, dogs, cars, trucks, lawn mowers, planes overhead, helicopters, trains, wind, rain, thunder, etc.), and decide how quiet things must be INSIDE your studio. Once again, subtract the small number from the big number, and the answer is how much isolation you need.

In the meantime, I wanted to ask about ventilation. If the room is airtight, how do you get air in AND out without sound escaping?

You build HVAC silencers, and put them in-line with your ducts. There's quiet a few examples in the forum about how to do that, but a silencer is basically a large box, lined with insulation, and with several baffles that force the air to take winding, zig-zag path through the box. Air can do that, but sound cannot.... :) - Stuart -

Yes, it is unusual.....but they don't provide any numbers.......true, I will have to set limits and decide what is "reasonable".....I'm very mindful of keeping neighbours happy so want to make sure this is done well..... Lawn mowers are very loud and everyone in my area uses them so I think if can get a reading of that, then that's probably reasonable, but at night I think would be a different story......anyway, will provide more details on that once I've got some figures. I've checked out examples on the forum of how to build HVAC silencers, but they all seem to be for using ducts....which I don't think I want to do, and don't have the space to run a ducted system.......I would like to have air coming in, and going out, that's for sure,...but I only have 95mm studs.......can I have a vent on the inside connected to a vent on the outside and use the silencing design to ensure sound is stopped, without running ducts and using the 95mm spacing I have? This raises another issue that I need to carefully consider: power points, light switches and light fittings......how do you install these without jeopardising all the work done to make the room airtight?......holes will need to be drilled to get any cabling through.........how do you deal with this? Thanks again......I think these are all things I need worked out before I proceed further with my design..... Adam

...but I only have 95mm studs......

Yes, but that's only one wall. You still need to build the other wall, if you want good isolation. A normal single-stud wall with a sheet of drywall on each side will give you made 30dB of isolation. Practically nothing. To get any kind of reasonable isolation, you need decoupled two-leaf MSM isolation, which usually means taking off the drywall from one side of that first wall, building a second stud frame a few cm away, then putting drywall on that. In any case, regardless of the wall, the silencer does not usually go inside the stud space. It CAN go there, but is much more commonly put on one side or the other.

but they all seem to be for using ducts....which I don't think I want to do,

Tehn how do yo plan to get the air from outside of the building to the inside of your room, and vice versa? I can't think of any other way to do that, then with some for of duct. You can't just open a window!

This raises another issue that I need to carefully consider: power points, light switches and light fittings......how do you install these without jeopardising all the work done to make the room airtight?.....

You surface-mount everything inside the inner leaf. In other words, on the drywall facing into the room. There is one single penetration of the isolation system to bring power into the room, and from there it is distributed entirely inside, with no further penetrations. All cables are run in surface-mount ducts, and all switches and plugs are surface-mount.

I think these are all things I need worked out before I proceed further with my design.....

Probably not! :) There are normally dozens if not hundreds of things that need to be taken into account when designing a studio. HVAC and electrical are just two of them. - Stuart -

Thanks again,..... unfortunately my room isn't big enough to build a second stud frame.... I would like to design it in a way where I don't have to do this....purely because I won't be left with much of a room afterwards... My plan was to use 25mm thick plywood on all exterior walls, roof etc......then packing with insulation...then on interior walls and ceiling, using 1 layer of 12mm thick ply followed by 1 layer of 16mm thick plasterboard.......with the floor, laying 25mm thick plywood, then neoprene mat followed by underlay and carpet.....the floor will also have 25mm ply under the joists and packed with insulation...... I know it's difficult without any numbers/figures of sound levels of my playing etc........but how effective would this design be? Re: airvents.......I assume you were joking about opening the window :D ........I guess my question was, can you install vents and silencers without having air con/heating untis as well......temperatures don't changed that radically here.....I just need to get the air in and the air out.......will vents alone with silencers do this? Thanks, Adam

I know it's difficult without any numbers/figures of sound levels of my playing etc........but how effective would this design be?

Unless you decouple your inner leaf from your outer leaf, it won't be very effective. The single biggest issue with walls that are not decoupled, is that sound hitting the inner surface is transmitted directly to the outer surface via the studs. If you want isolation, you have to break that direct path somehow. If you don't have space for a proper second stud frame, then there is an alternative, called "resilient channel". It is a special type of metal channel designed to do exactly that: decouple the drywall from the studs, acoustically, so that the sound is not transmitted through that path. Take off the drywall on the inside of your room, put resilient channel across the studs, then put up your plywood and drywall on the resilient channel, taking great care to make sure that the screws do NOT touch the studs anywhere: the screws must ONLY go into the resilient channel. If you do that correctly, and also fill the entire wall cavity with good insulation, then that will help a lot to isolate your room. Do the same with the ceiling: Take of the existing ceiling, put resilient channel across the joists, and put two layers of 5/8" drywall up there, with plenty of insulation in the space above.

then on interior walls and ceiling, using 1 layer of 12mm thick ply followed by 1 layer of 16mm thick plasterboard.

That's fine, but put the plywood on FIRST, and then the second layer is the drywall. So the plywood is screwed directly to the resilient channel, then the drywall is screwed to both the plywood and into the resilient channel. Also, 12mm is too thin: use only 16mm (or 15mm) drywall.

with the floor, laying 25mm thick plywood, then neoprene mat followed by underlay and carpet.....the floor will also have 25mm ply under the joists and packed with insulation......

I'm not too sure how well that will work: it sounds like it will be sort-of decoupled, but not actually floated... I think I'd put an extra layer or two of that plywood on there, for extra mass, specially seeing that you are going to be playing drums in there. That implies impact noise, so more mass will help a bit with that. But forget the underlay and carpet! Carpet is a terrible choice for studio flooring. It has the exact opposite characteristics of what you want: It absorbs sound selectively, absorbing a lot of highs, only some mids, and no lows at all. You need to do the opposite in a small room: You need to absorb lots of lows, and not touch the highs! Think of it this way: when you see photos of world-class studios, how many of them have carpet on the floor? :) Zero. I'd suggest something like a ceramic tile floor for that room. If the structure is tough enough to take all this weight, then you could put down a layer of tile backer (the thicker the better) then lay thick ceramic tile on that. That would give you a great floor, acoustically, that would also be good for isolation. Of course, you'd have to treat the rest of the room accordingly, but you'd have to do that anyway.

I know it's difficult without any numbers/figures of sound levels of my playing etc

Yup! It sure would help if you could get a sound level meter! They are not expensive: you can pick up a decent one, new, for less than US$ 100 on e-bay, and it will be VERY useful for you, always, not just in designing your room. I have a couple of them that I use all the time. Once you have one, you wonder how you ever lived without it!

Re: airvents.......I assume you were joking about opening the window :D ........

Yup! Excuse my attempt at humor.... I guess I shouldn't go auditioning for Comedy Central, right? :shot:

I guess my question was, can you install vents and silencers without having air con/heating untis as well......

Well, you can, yes, but you still need some type of ducting, just to get through the walls, even if you make it out of plywood yourself. You have to guide the incoming airflow from the outside, through the filter, fan, silencer, wall, and register. And you have to guide the outgoing air through the register, wall, silencer, fan and filter. You can't just cut a hole in the outer leaf, another in the inner leaf, and stick to simple vents in them.

temperatures don't changed that radically here.....I just need to get the air in and the air out.......will vents alone with silencers do this?

You might be surprised how fast the temperature will rise inside your room! It is going to be double-sealed, totally airtight, and really well insulated, from both the isolation system and also the treatment. You'll be in there (human bodies generate heat), playing hard (more heat) with lights and equipment turned on. Maybe more people with you in there too. The heat has no place to go! The ventilation system will only move some of that heat out, and it can get rather warm in there, pretty fast. There's also another major issue: humidity. Instruments, microphones and some equipment is sensitive to humidity, and very sensitive to sudden changes in humidity. People emit moisture, bot from breathing and from sweating: the harder you play, the more moisture you are putting out into the air. If you don't get rid of that moisture, the humidity rises really fast, affecting the sound of your instruments, and your mics, and your equipment. Air conditioners are good at getting rid of humidity, as well as being good at cooling. A small mini-split system only costs a few hundred dollars, and will take care of both the humidity and the cooling, while your fan-and-silencer system takes care of the ventilation. - Stuart -