Is there a magic size?

Hi all, Been reading many things on here and learning, plus the Rod Gervais book 'build it like the pros'. Basically i have about a 10m x 11m plot of land at the bottom of my garden and i plan on building my own studio (1 room, no need for mic's, live rooms or anything, i make Techno, so just drum machines and synths to record in) I plan on making the studio about 5mx3m internal size. My questions is, im worried about the interior size - can i just pick my size and get on with it? Or are there dimensions to be avoided? It's really freaking me out. Any help or advice would me gratefully appreciated. Thanks :)

My questions is, im worried about the interior size - can i just pick my size and get on with it? Or are there dimensions to be avoided?

Magic size for what? :) Are you planning to record and mix in there, or just do some jamming? For mixing, the recommended minimum size is 20m2 (about 215 ft2). That doesn't mean that anything smaller is terrible: it just means that it's harder to make it workable. The smaller you go, the more treatment you'll need, and the harder it gets. That's for mixing. For jamming / rehearsing / tracking, the room really should be bigger than that if you want to get a good sound out of acoustic instruments. Instruments "like" large rooms with high ceilings. That's where they always sound best. Small rooms sound "small", both in person and also with recorded tracks. If you only ever plan to close-mic everything and add ambiance electronically, then that's one option, but if you want natural room sound in your mixes, then small rooms are not good for that. A few years ago, Sound on Sound magazine did some tests in several major studios, taking he exact same drum kit, drummer, mics, gear, and everything from place to place, setting them up in the live room, and recording the exact same song played the exact same way. Not surprisingly, the larger rooms sounded better. And those were all high-end pro recording studios, well treated. So basically: for mixing/mastering, go with around 20m2 floor area. For tracking/rehearsing, go with "as big as you can possibly make it".

are there dimensions to be avoided?

Not specific dimensions, no, but the relationship between dimensions can be an issue. Thus, your length, width, and height should NOT be the same as each other, nor within about 5% of being the same. And the room should not be more than about 3 times longer than it is wide or high. There are other rules-of-thumb, but once again, it depends on the purpose of the room: one set of rules for control rooms (mixing/master), another set for live rooms (rehearsal/jamming/tracking). - Stuart -

Thanks! It will be a room for jamming and mixing. Note - Not jamming with mic'd instruments like guitars or drums - i'm working with drum machines and synths which will be recorded into the computer via a mixing desk, so the room sound is not important in that respect, but for mixing its still important obviously. I make electronic music, techno. I was more concerned about getting the room dimensions wrong incase i end up with these room nodes or something thats unwelcome.

but for mixing its still important obviously.

For the electronic stuff, there's no problem then. But for mixing there sure is. Use one of these Room Ratio calculators to figure out the best dimensions for your room: http://www.bobgolds.com/Mode/RoomModes.htm OR http://amroc.andymel.eu/ https://amcoustics.com/tools/amroc Both of those are very good, and will help you to decide how best to build your room. They give you tons of information that is really useful to help figure out the best dimensions. But basically, you should worry about maximizing the room volume. That's the first priority. Largest possible amount of air inside. Then if the calculators show that the ratio is terrible, adjust a little bit. But don't go crazy over ratios. If you want to understand all of the aspects that you should be considering when designing your room, then google a document called "ITU BS.1116-3", download it, and look at chapters 7 and 8 (the other chapters are not relevant to what you are doing, so you can skip them). That lays out what you need acoustically for a "critical listening room", and that's what a control room is. If you can, make your studio a little larger, so you can get about 20m2 of floor area. That's the final floor area, after the isolation walls are in place. You should also consider height: Try to get at least 2.5m, and here too, more is better: if you can 3m, that's fantastic. - Stuart -

Thanks Stuart, really appreciate this advice. Had a look at bob golds calculator but have no idea how to use the data it came back with :?: I'll see if i can get 5m x 4m interior, i forget now what the height allows here in the UK. Will report back soon to this thread with pics and info :)

Soundman2020 wrote:

Then if the calculators show that the ratio is terrible, adjust a little bit.

I like the amroc site, i put my 5mx4m x 2m height data in and got the results back, but what would terrible ratios be? Also, would 5x4m be considered too close to being square, would i be better off going for 6mx4m or 5mx3m for example so its more of a rectangle? Thanks

elastic wrote:

Soundman2020 wrote:

Then if the calculators show that the ratio is terrible, adjust a little bit.

I like the amroc site, i put my 5mx4m x 2m height data in and got the results back, but what would terrible ratios be? Also, would 5x4m be considered too close to being square, would i be better off going for 6mx4m or 5mx3m for example so its more of a rectangle? Thanks

Hi elastic, The bob gold calculator has 3 tests that the room ratio is tested against. They're a good pointer as to whether your room dimensions will be a good starting point. (BTW 6m x 4m x 2.4m passes all 3 tests). As regards to your suggested dimensions : If you can afford 6m x 4m then go for that over 5m x 4m. The additional 9-10m3 of volume is worth it being pushed a little out of the bolt area (another guide to whether room dimensions are good). You will have a greater distance behind your head at the mix position, which will just about be enough to avoid reflections within 20ms (pretty much required for good mixing) and therefore greatly simplifying the rear wall treatment design. Dan

Ah that’s great advice thanks Dan. Much appreciated. Yes I was struggling to read the results of those sites due to my lack of knowledge. Makes sense about what you say though with regards to a more lengthier room. What would be a desired wall construction and thickness? I was thinking of using Sips panels (the acoustic type) then a stud wall inside. I think it was Rod Geiger who suggested a 2 leaf system? Once I know my wall thickness I can get to laying the concrete base down.

Ok so been doing lots of learning and reading and mocking up sizes on site. I’d be comfortable doing - Width - 5.5-6m Length 3m or 3.5 Height 2.5m I like the idea of using sepmeyers ratio to scale it to my size. I used this link to work test some sizes according to his ratio - http://www.odometer.org/misc/ht/ I presume the thing to keep in mind when using his ratio is, even though it can be scaled down to small sizes, they would not be ideal. Best to use his ratio and try and get the biggest room that fits my budget and area I have to work with.

Remember at such sizes the ratio is not the most important part. You say 5.5-6m length and 3-3.5m width, if you can fit 6m x 3.5m x 2.5m and can afford it then do that, regardless of the ratio. If you can push to 3.6m width you'll even pass the 3 bbc tests. Just think pure volume at first. What can you fit and what can you budget. If you can budget for 2.8m height then do it, if you can budget for 4m width then do it. Put your biggest volume into the Bob golds calc, and adjust that slightly to pass the tests and get near the bolt area. Dan

Thanks Dan, appreciate that. Will keep planning. Something I’m struggling with is working out what level of isolation I require in the walls, so I can then figure out how thick the walls will be so I can the work out the size I can build.

With regards to isolation you need to know what you dB you produce first, then minus what you need it to be outside. For example: If you make techno music at 80dB, you need that to be down to 34dB at the closest neighbours boundary. (It could be legally you're allowed more than 34dB, it depends where you are. Basically measure the ambient noise on a quiet evening, if it's above 24dB (it will be) then add 10dB to that for the legal limit in your area). So you would be looking at 46dB of isolation needed if you worked at 80dB. You can take 6dB off that for each doubling of distance to your room. For example: Neighbour's boundary is 1m from the closest studio wall, take away nothing. Boundary is 2m away, you can take off 6dB. Boundary is 4m away, take off 12 dB. And so on. This gives you your legal isolation requirements. You would definitely want to be have a bit more than this though just in case. Dan

Most of the work in the textbooks on Room Ratios is old and not about ours sized Rooms but Concert Halls. The Ratios do not scale. Repeat they do not scale. Check out Cox's work on more robust ratios and ones suited to small rooms. Then consider my good friend boggy's comment that there are no modes in his treated rooms...... Also plasterboard does not support the lowest modes anywhere near how concrete does, and these ratios are generally presuming a very massive hard boundary. Soundproofing is difficult to achieve, particularly at LF. I suggest playing typical trax at typical volumes, then go forth and listen with a Sound Level Meter in hand. C or Z Weighting for the SLM to hear the bass. DD

Then consider my good friend boggy's comment that there are no modes in his treated rooms......

I would beg to differ! There are ALWAYS modes. The simple fact of having walls, floor and ceiling creates the modes. The treatment might well damp them into oblivion, but they are still there, and still shape the overall frequency response. From that point of view (treating modes into oblivion), here's a couple of rooms with "no modes": viewtopic.php?f=2&t=20471 viewtopic.php?t=21539 ... and built very simply, too... :) The only way to have a room that really does have no modes, is to use a bulldozer... :) Flatten the entire building, so there's nothing around but empty air, and you do indeed have no modes... - Stuart -

Of course modes are usually detectable in inadequately treated rooms. But how significant relatively? Everything Acoustic is relative and spectrum dependent. Boggy's have typically four feet of absorption on opposing walls. Newell much more. I wouldn't hazard a guess as to what level of mode is 'significant' but IMO a holistic view is preferable to focussing on just one aspect, which may well not be at all the most powerful one at play. http://forums.musicplayer.com/ubbthread ... ven_matter As Cox and others have pointed out the old optimal ratios do not scale to small listening rooms. http://www.acoustics.salford.ac.uk/acou ... nt=methods I would always add that sound travels slower in fibre so the visible dimensions of the boundary room are quite different from the finished treated acoustic dimensions. Very different in a deeply treated room. I reckon most of us will agree that bigger is generally better, particularly as it can include treatment. IMO the Back Wall is typically the biggest factor at play, and most often inadequately treated. The second biggest factor is see is the almost absurd practice of placing the listener Mid Width AND Mid Height. DD

Of course modes are usually detectable in inadequately treated rooms. But how significant relatively?

I think maybe I didn't explain the point very clearly... It's not an issue of weather or not modes are detectable, but rather the simple fact that the modes themselves (not the ringing! Just the mode...) are what shape the frequency response of the entire room, and the entire spectrum. Absorption is largely irrelevant here, since it doesn't change the modal response: it just damps the ringing. I'm not sure if you have Kleiner and Tichy's book on small room acoustics, but they explain the issue quite clearly: The overall steady-state frequency response is determined by the modal response. And damping doesn't do a lot to change that: Even with high damping (lower graph) the frequency response is not getting flat: In other words, the modes are still there still making their effect "present", even though the might be highly damped, and not ringing at all. The modes are "detectable", regardless of weather the treatment was "adequate" or not. Hence, there's no such thing as "no modes in a room". It's certainly possible to have a room where the modes don't ring: that can be done in any carefully designed room of reasonable size). But the modes are still there: the modal response still has a large effect on the overall frequency response of the room, even if the time-domain response is smooth, with no modal ringing.

I wouldn't hazard a guess as to what level of mode is 'significant'

In the second graph above, I'd say that the remaining modal "ghosts" (to coin a term" are very much significant, despite the damping: there's still wild swings on SPL, over a range of 30, 40, and even 50 dB.

...bigger is generally better, particularly as it can include treatment.

Yup! For sure! You can get more of the spectrum above the Schroeder frequency, and into statistical territory. That's always a good thing.

the Back Wall is typically the biggest factor at play, and most often inadequately treated.

Yup. Many first-time studio builders greatly underestimate the effect of the rear wall, and can't understand why you need a meter or so of treatment back there, wanting to put up one inch of foam instead... :roll:

the almost absurd practice of placing the listener Mid Width AND Mid Height.

Yup! If only architects would be back to building ten foot ceilings in houses, or at least 9 foot ceilings! It would make things a lot easier. Or maybe persuade engineer to start mixing while crouching down low, sitting on a 6" kiddie chair... or sitting way up high on a bar stool! :) Not much we can do about side-to-side, but vertically it would be nice to have more options. - Stuart -

Waka wrote:

With regards to isolation you need to know what you dB you produce first, then minus what you need it to be outside. For example: If you make techno music at 80dB, you need that to be down to 34dB at the closest neighbours boundary. (It could be legally you're allowed more than 34dB, it depends where you are. Basically measure the ambient noise on a quiet evening, if it's above 24dB (it will be) then add 10dB to that for the legal limit in your area). So you would be looking at 46dB of isolation needed if you worked at 80dB. You can take 6dB off that for each doubling of distance to your room. For example: Neighbour's boundary is 1m from the closest studio wall, take away nothing. Boundary is 2m away, you can take off 6dB. Boundary is 4m away, take off 12 dB. And so on. This gives you your legal isolation requirements. You would definitely want to be have a bit more than this though just in case. Dan

So i took a reading on the plot of land where the new studio will be. I went out when it was generally a quiet time, 9pm - At my neighbours fence it read 45dbc (i used an spl meter app on my phone with it set to slow and 'c' rating) I measured what i work at in my studio and its generally around 80dbc I am not concerned with sound coming into the studio as i am not mic'ing/recording anything inside and its generally quite quiet outside. My main thing now is i'm looking at building about 0.5m from the fence - so we can save space down there, but i think to do that i am going to need to get planning permission. As i understand it if you come in 2m from your borders then you don't need planning permission up to a certain degree.

elastic wrote:

So i took a reading on the plot of land where the new studio will be. I went out when it was generally a quiet time, 9pm - At my neighbours fence it read 45dbc (i used an spl meter app on my phone with it set to slow and 'c' rating) I measured what i work at in my studio and its generally around 80dbc I am not concerned with sound coming into the studio as i am not mic'ing/recording anything inside and its generally quite quiet outside. My main thing now is i'm looking at building about 0.5m from the fence - so we can save space down there, but i think to do that i am going to need to get planning permission. As i understand it if you come in 2m from your borders then you don't need planning permission up to a certain degree.

A phone app isn't going to be accurate in any way really. So I would take that with a pinch of salt. 45dBC seems quite loud. You might want to try in the night to see what it's like without traffic. If the measurement is accurate then you could legally produce 50dBC at your boundary. You can easily get 40dBC of isolation in your studio. Just having seals on your (back to back) doors, sealing all the gaps in your wall leaves and adding a silencer box on the HVAC inlet and outlet can achieve that. So that would put you 10dBC below the legal limit, which seems a good target. In the UK you don't need planning permission for an outbuilding in your garden, as long as you follow the "permitted development" rules. Check the planning portal website. You may find (like me) that it's better just to get planning permission anyway (about £200) and then you can have a lot more freedom to go bigger etc. Within 2m of the boundary limits you to a max height of 2.4m external height when building under permitted development rules. That includes eaves and roofing materials etc. You would have to dig down and have steps into the studio if you want a higher ceiling (aka. be silly). Just pay the £200 and then, providing the location for the studio doesn't block your neighbours light or view more than other surrounding trees/buildings it will be fine. The biggest expense on the council side of things is building regs. You may not need the inspecitions though if it's just you using it and it's not having member of the public in it, check with the council. For planning permission you need some basic drawings of the elevations and a location plan (you can draw these yourself), with dimensions, and the details about the facing material you'll be using. Dan

Thanks for that Dan appreciate the help. I will check at night with my app, there is no traffic where we live really, but will check again. I would prefer to go closer to my neighbours fence, i was thinking about 0.5-1m away from the left and back fence. If we come in 2m - great its permitted development but we then lose a lot of wasted land around the sides of the studio as its kind of dead space then. Great to know about the approx price. £200 is ok. I was skeptical about drawings though, i figured i would have to get drawings done by a structural engineer type person. I read on another website that planning permission had been rejected for someone because the drawings weren't good enough. Yes it will just be me using it, no member of the public. Should i tell the council it will be a music studio, or just say it will be a man cave type of thing. The studio will be far down the garden (about 35m from the houses) and my neighbour knows what im planning so putting it a bit closer to the fence should be ok, i will ask him first of course. Here's a pic of the land - The plot ive got to work with is 10m wide 11m deep I'm thinking of building with SIP panels, i wonder if i will need a room within a room type of thing or if a single skim wall will be enough for my needs? Also thinking the floor and roof to use SIP panels. Ever used or know anything about them?

elastic wrote:

Thanks for that Dan appreciate the help. I will check at night with my app, there is no traffic where we live really, but will check again. I would prefer to go closer to my neighbours fence, i was thinking about 0.5-1m away from the left and back fence. If we come in 2m - great its permitted development but we then lose a lot of wasted land around the sides of the studio as its kind of dead space then. Great to know about the approx price. £200 is ok. I was skeptical about drawings though, i figured i would have to get drawings done by a structural engineer type person. I read on another website that planning permission had been rejected for someone because the drawings weren't good enough. Yes it will just be me using it, no member of the public. Should i tell the council it will be a music studio, or just say it will be a man cave type of thing. The studio will be far down the garden (about 35m from the houses) and my neighbour knows what im planning so putting it a bit closer to the fence should be ok, i will ask him first of course. Here's a pic of the land - The plot ive got to work with is 10m wide 11m deep I'm thinking of building with SIP panels, i wonder if i will need a room within a room type of thing or if a single skim wall will be enough for my needs? Also thinking the floor and roof to use SIP panels. Ever used or know anything about them?

Not preserved: Screen Shot 2019-05-22 at 21.42.56.png

You can definitely go within 2m of the boundary (even within permitted development), but without planning permission you're limited in height to 2.4m. I wouldn't worry about the drawings being too simple, it really doesn't matter for planning permission (it's more involved for building regs). Mine were really simple, you can view them here: https://planning.sholland.gov.uk/OcellaWeb/showDocuments?reference=H17-0553-17&module=pl I put music studio on my application, they just stipulated I shouldn't have opening windows. I definitely wouldn't go with SIP panels. They're just OSB either side of polystyrene insulation. That will give bad isolation. If you go single skin you would want to go for brick, it may be difficult to deal with condensation, in this case though. If you only want 40dB of isolation, you might be able to get away with a single timber frame with resilient channel for the inner leaf. Or you can go with a semi decoupled timber frame by using a 150mm sole plate and head plate and then using 100mm studs staggered. The best is room within a room as you know though. In the end, if I was doing 40dB isolation, I wound go with resilient bars, and do it all DIY to guarantee there aren't mistakes by builders screwing through to the framing instead of just the bars. That would be cheaper and save floor space over room within a room. But would be possibly 10x (10dB) less isolation with the same sheathing materials. Dan

Dan you're a gent, seeing your application was great. Thanks for that. My size is similar to yours. I'm looking at about (internal) 5.5m x 3.5m with 2.5m height minimum I've started my application online, completed a load of it already, just need to finalise my design and get the drawings done (finance is going to do them). Its the walls im struggling with lol SIPs not looking good, i like those resilient bars idea but i don't like the lack of isolation. I don't want brick. I think i like the idea of a 2 leaf system. Would i be right in thinking with a 2 leaf system, you basically build 2 stud walls, stuff them with rock wool, then for best practice put acoustic plasterboard on the room side stud and on the outer stud. Still not 100% sure on it all but eagerly learning as i go! This picture is the wall i am aiming for. 2 layers of plasterboard on each outside face of both walls. (i don't pay much attention to STC ratings as they are calculated based on the frequency range of human speech not music) - but you get the idea. Edit - just reading about these RC1 and RC2 bars. Interesting stuff. Imagine if you did a 2 leaf wall system then added the resilient bars as well. less space but big isolation surely? I won't do that but just intriguing.

elastic wrote:

Dan you're a gent, seeing your application was great. Thanks for that. My size is similar to yours. I'm looking at about (internal) 5.5m x 3.5m with 2.5m height minimum I've started my application online, completed a load of it already, just need to finalise my design and get the drawings done (finance is going to do them). Its the walls im struggling with lol SIPs not looking good, i like those resilient bars idea but i don't like the lack of isolation. I don't want brick. I think i like the idea of a 2 leaf system. Would i be right in thinking with a 2 leaf system, you basically build 2 stud walls, stuff them with rock wool, then for best practice put acoustic plasterboard on the room side stud and on the outer stud. Still not 100% sure on it all but eagerly learning as i go! This picture is the wall i am aiming for. 2 layers of plasterboard on each outside face of both walls. (i don't pay much attention to STC ratings as they are calculated based on the frequency range of human speech not music) - but you get the idea.

Not preserved: Screen Shot 2019-05-24 at 23.05.21.png

No problem 8). For decoupled room within a room you build two free standing rooms. The outer frame has 4 walls and roof trusses/joists sitting on it. The inner frame has 4 walls and ceiling joists sitting on it, and doesn't touch the outer framing at all, at any point. You would want 2 layers on each leaf yes, but the first layer wants to be structural, eg. OSB3 or ply wood, to prevent horizontal movement. I used 18mm OSB3 and 15mm standard plasterboard (not acoustic) as it's similar mass to 12.5mm acoustic plasterboard but cheaper. Inner leaf needs polythene vapour barrier behind the OSB3 and outer leaf needs a breather membrane on the surface of the OSB3 (I put the outer leaf plasterboard between the studs tight against the OSB3 as it's not for exterior installation). I decided to go with a timber cladding for my outer facing material (yes it's technically a third leaf) as it was the simplest option that controlled moisture by allowing the OSB3 to dump the moisture in the ventilation air gap behind the cladding. There are other possibilities for facing material, but this one seemed simplest to me. Dan

Interesting stuff. Imagine if you did a 2 leaf wall system then added the resilient bars as well. less space but big isolation surely?

If you have a decoupled two leaf wall, then there's no benefit from decoupling again with resilient channel. Well, there IS a benefit: but it's for the pocket of they guy who sells you that stuff! :) There's no acoustic benefit for you. That would be sort of like swimming down to the bottom of a swimming pool to get very wet, but taking a hosepipe down with you to get you even wetter.... :) - Stuart -

Haha brilliant Stuart!! Well explained :) Great advice Dan, thanks for that. Some things to think about for me. I will try and work out just how thick the walls will be by doing a two leaf system compared to doing a single leaf and resilient bars. Floor space saved Vs Isolation Did you put the door on the back/front of your studio for any reason? I'm looking at putting the door (single or double doors not sure yet) on the side. I hear the back wall is sacred and i will be working towards the front wall.

elastic wrote:

Did you put the door on the back/front of your studio for any reason? I'm looking at putting the door (single or double doors not sure yet) on the side. I hear the back wall is sacred and i will be working towards the front wall.

I didn't :lol: that was an old design before I had researched properly. My door is in the side and I didn't install windows, I'm putting a window in the door though. Dan