John Sayers' Recording Studio Design Forum Archive

Hi Everyone,

I've only just discovered this wonderful forum and this is my first post. There's so much amazing information here which I'm very slowly working my way through.

I hope this isn't rude to jump straight into asking for advice but I could really use some! Thanks very much in advance for reading.

I'm a producer / composer based in London, UK and planning on building a studio in my garden. Primarily for use with Near Fields and Sub (Never very loud) and occasional drumming. Using a Garden room company that appears to have experience in sound proofing we've come up with a design that should sound proof around 50db RW (56db from walls and 48db from ceiling). I realise this basically ignores bass transmission but I'm quite limited in space (for a room within a room) and only plan on using the studio during normal working hours.

All this aside the main reason i'm here is for a little help on getting the room to sound nice internally.

I'm learning how use sketchup but for now hopefully the company's drawing will do.

It's not clear from the drawing but each wall is each 210mm thick. The shape is a bit strange as we have to build around a big tree! Hopefully this triangle cutout might actually help acoustically (breaking up potential parallel walls)? The ceiling height externally goes from 2.8m on the left hand side corners down to 2.5m on the right hand edge, internally this is 2.45m and 2.15m respectively.

As the internal dimensions can be jigged about a bit my gut feeling is to build in bass traps into the three available corners (four if the doorway is moved to the left a bit) and skewing the back wall a little so its no longer symmetrical with the front wall.

I plan on having the speakers in the middle of the right hand wall facing the triangle cutout if that makes sense.

As you can probably tell i'm a complete noob when it comes to this and would greatly appreciate some help.

Many thanks,

Clive

.. Just realised I added the wrong picture for the company's sound proofing, here is the correct one.

Hello CliveFromAccounts,
Welcome aboard the roller-coaster! The amount of reading and gaining relevant knowledge involved in simply developing a design for a studio is enormous (as I'm sure you're aware) - the learning curve is very steep. The process should start with deciding what you need the space for (as you have done) and then measuring how loud that activity is. It's only then that you'll know how much isolation you really need.

for use with Near Fields and Sub (Never very loud) and occasional drumming

OK - but exactly how loud? Buy a good quality sound level metre and measure in decibels the activities you'll be undertaking. Bear in mind that most drummers can reach 115 dB without breaking a sweat, so if your transmission loss is 48 dB that may well be too loud for a residential area.

we've come up with a design that should sound proof around 50db RW (56db from walls and 48db from ceiling)

That sounds fairly optimistic for a single leaf design or have I missed something here? As I understand it, Rw relates to the laboratory rated sound reduction index of a single element, but what you will certainly find is that even the most carefully executed builds are not perfect and will not return laboratory results. Even if this was the case, the RW 56dB rated walls and 48db rated ceiling would give you 48 dB of isolation overall at best (sound always finds the path of least resistance).

I plan on having the speakers in the middle of the right hand wall facing the triangle cutout

The more symmetrical mixing rooms are, the easier they are to treat and the better they will sound.

The shape is a bit strange as we have to build around a big tree!

Are you certain you can't remove the tree? It may make your project both easier and cheaper. Please don't think I'm trying to discourage - far from it. The best advice I can offer is to urge you not to hurry. Do lots of research into similar projects, learn as much as you possibly can about acoustics before committing to a design and if you haven't already, read 'Home Recording Studio: Build It Like the Pros' by Rod Gervais forwards & backwards. I look forward to hearing more in the coming months - good luck & best wishes, John.

maybe you can incorporate the tree into the overall floor plan? rather than remove it, maybe get rid of as much of the angled structural walls and make them as straight. perhaps even it might be an option to enclose the truck into the overall foot print?

Thanks very much to getting back to John and Glenn.

John Steel wrote:The best advice I can offer is to urge you not to hurry. Do lots of research into similar projects

On your advice, John I've just ordered Rod's book and a nice SPL meter. Look forward to delving in deeper. I'll do some measurements of my typical studio levels and outside ambience and get back to you.
My feeling with the "56db" was quite similar.. a little bit of "too good to be true"!
As you say I think the best thing to do is not rush and take the time to learn as much as possible, very solid advice!

gullfo wrote:maybe you can incorporate the tree into the overall floor plan?

Thanks for the design Glenn, it looks very promising. I think it would add a bit towards the cost but i'd obviously gain a load of space. Would you say this kind of design is preferable in terms of internal acoustics?

I've actually booked a tree surgeon in to have a look this week. It's an Ash tree so is susceptible to Die Back and if this is the case then the decision to remove it will have been made for me.

I've just ordered Rod's book and a nice SPL meter

yes, more room volume would be better acoustically, and of course if the tree can be removed then that will give you a nice rectangular space to work out the design in rather than working around something that is not helpful.

Ok so a lot has changed since the first post!

The tree in the garden has a very high chance of disease so we're going to remove it. That leaves a nice rectangular space with a width of 4.2m, length isn't so set in stone but I'd say max 5.5m.

The design I currently have is a 100mm breeze block outer shell (unsure what to do with the roof) followed by 75mm air gap, 100mm wooden studs plus 2x gypsum boards 25mm. The air gap is a little small I know but I don't have much space to work with. My typical SPL was 60-75dbc anyway so not huge (ignoring occasional drums).

I have been trying to plan the best internal dimensions ratio I can using Rod's book and Trevor Cox's / Amroc calculators. So with dimensions of H 2.3 x W 3 x L 4.38 I can get bang on to Louden's second best of 1: 1.30: 1.90.

The trouble is this appears to be in a bad zone on the Cox Calculator?! By changing the length to 4.65 I gain Volume and also get into a good area on the Cox calculator but slip out of the Bolt zone slightly.

It'd be great to hear what people recommend!

I reckon you probably have a limit on the size allowed before requiring planning permission.
Here, I think it is 25 sq metres, with a 4M max roof height (to accommodate A roofs)
I would go for the max here. Ratios are iffy in many ways. You will find the Cox states that Bolt and all those historic ones are based on Concert Hall sized spaces and THEY DO NOT SCALE.

Be sure to include insulation in your void between bricks and inner skin. You might need to use a layer of PUR Kingspan etc. for thermal reasons plus a Fibre layer for acoustic reasons.

Paulus87 is in the UK and an experienced builder, hopefully he will join us.

Thanks Dandan,

For us, with the structure being near the boundary, the max height is 2.5m without planning permission. We’re toying with the idea of digging down 400mm and then building the concrete slab up and around the sides. Door opening becomes a bit of an issue but if I can find a solid enough glazed (really want natural light) single door, it could open inwards. Alternatively I could make the internal door frame a bit wider so they can both open inwards.

Good to know about the ratios, very much leaning towards a 4.65 length in that case.

Was definitely planning on insulating the cavity for acoustic reasons, would be good to hear about thermal suggestions too though.

I’m having a bit of trouble planning the roof.. if we were to use wooden studs + gypsum for both internal and external ceilings the TL wouldn’t match that of the walls. Would it be ok and safe to then put a layer of the same 100mm concrete slabs on top to increase the mass?
We have also allocated 200mm on top of that to add a 6degree slope (A shape from the width middle) for drainage. So 2.9m minus 0.4m making 2.5m

I’m having a bit of trouble planning the roof..

In order to match the density of your block walls, I think a concrete beam and block roof is probably the best solution. I'm sure you're aware of this but I'll mention the necessity of hiring a structural engineer for technical input on this - it's not something to be guessed at!
I think DanDan is spot on regarding ratios. If you have a limited amount of space for your studio, it's more important to utilise the available space than conforming to a theoretically ideal ratio.
Apols if I'm preaching to the choir again here, but have you seen Gregwor's transmission loss calculator? It's an immensely useful tool for modelling the effects of mass and air gap in studio construction.
https://johnlsayers.com/phpBB2/viewtopi ... =1&t=21770

ATB JS.

Thanks John, yes I’ve been using the TL calculator.. very handy indeed!

A concrete beam and block sounds ideal although I’m a little concerned about the logistics. There isn’t much access at all for machinery. Could the beams be poured in situ?

An alternative could be thick wooden joists with a ‘living’ soil roof on top. We would, like you said, have to consult a structural engineer but this could potentially solve the drainage and mass problems.

Could the beams be poured in situ?

Without research, I couldn't say for sure - something tells me this ought to be possible.

An alternative could be thick wooden joists with a ‘living’ soil roof on top.

Again I don't see why it couldn't work. You'll probably need pretty hefty joists reinforced with flitch plates or steel i-beams to support it. I don't know anything about the ongoing maintainance of living roofs and I'm guessing they're much heavier in the wetter months of the year, so the insulation may vary over time. Interesting idea tho'.

A lot to think about. Cheers John!