Building Home Studio - concept plan reveiled - feedback?

Hi, I recently bought a house at a recreation compound/garden association. There is also a small building present. And here I want to build a studio. I've added some pictures, so you have an idea about the surroundings. If you wan't more, I'll make them for you. It's quite small and far from ideal, I know. But this is what I have. And I also see this project as an experiment. Because in the future I would like to make a bigger studio. The dimensions: L4,73 x B3,35 x H2,23 (till wooden beams) H2,94 (till the highest point) = 15,85 square meter. What do I want to do there? Ideally jam with a small band, record songs including drums. The (basic) plan: make a room within a room. Remove the floor tiles, dig a little (it's not that high and I wan't to avoid building around the roof structure, easier to stay below) and pour concrete in it. The inside wall will begin at the end of the concrete, and there will be a gap of 1/2 cm or so to the outer wall. The walls will be structured like this (from inside to outside): 1,25 cm plasterboard + green glue + 1,25 cm plasterboard --- wooden studs filled with rockwool --- 1,25 cm plasterboard. If we build it like this, there is 13 square meter or so left. Of course, the hard parts are yet to come. Electricity, airco/heating, doors etc... But I wanted to check with you, if this basic plan is solid. The hardest thing for me was to determine the ratio mass and spring... I've searched for calculations etc. but couldn't find anything. What do you guys think of this?

Welcome!

I've added some pictures, so you have an idea about the surroundings.

Unfortunately, I see no pictures :(

What do I want to do there? Ideally jam with a small band, record songs including drums.

How far away from the building is your property line? Drums + band = very loud.

dig a little (it's not that high and I wan't to avoid building around the roof structure, easier to stay below) and pour concrete in it.

Good idea. Dig a lot, not a little. I haven't seen your pictures yet, but you are going to need a LOT of space above your inner room for HVAC.

The inside wall will begin at the end of the concrete, and there will be a gap of 1/2 cm or so to the outer wall. The walls will be structured like this (from inside to outside): 1,25 cm plasterboard + green glue + 1,25 cm plasterboard --- wooden studs filled with rockwool --- 1,25 cm plasterboard. If we build it like this, there is 13 square meter or so left. The hardest thing for me was to determine the ratio mass and spring... I've searched for calculations etc. but couldn't find anything.

At the very top of this Studio Design forum thread, there is an MSM calculator. Here is the link to make finding it easier for you: Gregwor & audiomutt’s MSM Transmission Loss Calculator Version 2.03

But I wanted to check with you, if this basic plan is solid. What do you guys think of this?

I'll put money on the fact that your isolation plan is not enough IF your property line or neighbours house is close by. First off, a 1/2 cm gap between your inner and outer leafs is not enough to even avoid potential flanking. Wood warps. I've seen a lot of wood warp a full inch over time. That's a lot more than half a cm. Also, a single sheet of 1,25 cm plasterboard typically is far from enough to provide enough isolation for drums. Once you punch some info into the MSM calculator I provided above you will see the drastic improvements of adding a few sheets of thicker drywall and even a 2.5 cm gap. Now, again, HVAC eats up a lot of space. That's where the space above your inner leaf will help. Do not commit to anything until you fully draw up your design in SketchUp. The biggest part of your design is going to be HVAC. Also, you need to decide whether you want to just track the instruments there or mix as well. That is very small room to have a mixing set up AND double as a jam space. Greg

Do you see the image now? Otherwise you can see it here: https://ibb.co/QkD69TX The first house is within 5m or so. I think there's quite a bit of space above the inner room. The highest point will be around 70cm from the inner room. I think there's place for a HVAC there? I've also added a picture were I've tried to determine the space used for a band playing + a desk. It's cozy, for sure, but I think it is possible. And most of the time I'm there by my self, of with one other musician. What do you think is the best ratio between isolation/enough space and mass/spring (plasterboard/rockwool)? Or should I use other materials?

I'm also thinking about adding a layer of thin plasterboard or something else on the inside of the outside walls and the roof. To make it airtight and add a little bit mass

The highest point will be around 70cm from the inner room. I think there's place for a HVAC there?

Should be enough, but it might take some tinkering in your silencer box design to fit them.

I've also added a picture were I've tried to determine the space used for a band playing + a desk. It's cozy, for sure, but I think it is possible. And most of the time I'm there by my self, of with one other musician.

Your desk needs to be centered and your head should be between 20% and 40% depth in the room (not at or near the 25% mark though!)

What do you think is the best ratio between isolation/enough space and mass/spring (plasterboard/rockwool)? Or should I use other materials?

Those are great materials. You need to determine how much isolation you need and then use the calculator to figure out how to build it! Greg

Your desk needs to be centered and your head should be between 20% and 40% depth in the room (not at or near the 25% mark though!)

Can you explain this? I don't understand it completely... The calculator looks awesome!! Although I'm still figuring out how to use it correctly. Say I want gypsum + wooden frame with rockwool + gypsum --> where do I fill this in exactly? And it looks like you can only select mass material, no springs... And that's what I'm really curious about... Will I get better insulation if I choose for 3 cm gypsum and 5 cm rockwool, or if I choose for 5 cm gypsum and 3 cm rockwool (for example)? Of course you can fill in the air gap --> so that's a spring... And then there is also the outside wall, which consists of bricks, wood and windows... As you can see, I'm still trying to get a grasp on everything :D

Can you explain this? I don't understand it completely...

He means that having symmetry is critical to your room: your desk needs to be on the center-lined of the room, and the left half of the room needs to be an exact mirror image of the right half. If not, your stereo image and sound-stage will be "skewed", and your left ear will be hearing a different acoustic "signature" from your right ear. He also means that if you measure the distance from the front wall to the back wall, the your desk needs to be set up so that your ears will be somewhere between 30% and and 40% of that distance, so if your room is ten feet long, then the desk needs to be placed so that your chair (ears) will be between 3 feet and 4 feet away from the front wall. The "best" position is theoretically 38%, but most engineers and designers prefer a spot that is a bit closer to the front wall. 33% to 36% is usually fine.

it looks like you can only select mass material, no springs...

The air is the spring. By selecting the depth of the air gap, you are selecting your spring.

Of course you can fill in the air gap --> so that's a spring...

The air gap is not "a" spring... it is "the" spring! There's usually only one spring in an MSM wall system, and that's the air trapped between the leaves. (The exception would be if you did not fully decouple your leaves: eg, if you used resilient channel on the studs for the second leaf, then the spring is now a combination of the air AND the resilient channel, so the result is LESS effective than just the air alone, in a fully decoupled wall.) But for most studio walls, properly built as fully decoupled wo.leaf MSM systems, the only spring in the wall is the air.

Will I get better insulation if I choose for 3 cm gypsum and 5 cm rockwool, or if I choose for 5 cm gypsum and 3 cm rockwool

Tru it and see! :) In both cases, such a tiny air gap is not going to give you good results: generally you want at least 10cm air gap. On the other hand, 5cm of gypsum board is a good amount of mass, and 3cm is probably too little.

And then there is also the outside wall, which consists of bricks, wood and windows...

Calculate those separately, and use the result that gives the LOWEST isolation. So for example if your calculation for the part where you have brick says the isolation is going to be 45 dB, but the calculation for the part where you have glass says the isolation is going to be 35 dB, then assume the isolation of the entire wall will be about 35 dB. Isolation is only as good as the weakest part. - Stuart -

I am reading the book of Rod Gervais at the moment, but as you can see, I'm still a rookie on this subject.... Your input is really appreciated!!

He means that having symmetry is critical to your room: your desk needs to be on the center-lined of the room...

All right, that's clear to me now. And acoustic treatment etc. will be the next step. First the insulation. I know, of course, to keep the acoustic elements in mind.

The air gap is not "a" spring... it is "the" spring!....

Yes, all right, the air is the spring. But what about rockwool etc.? That is also a spring, right? And how does this relates to air? Which spring is better for insulation? Of course there need to be an air gap, because the rockwool is held together by wood studs, and those will resonate.

Calculate those separately, and use the result that gives the LOWEST isolation....

Noted! I will do this. I think 15 cm for each wall is the maximum I could lose, then I will have 13+ square meter left. Maybe this is a solution: put 12.5 mm gypsum on the inner side of the outside wall, to ensure there are no air gaps + to cover the windows. Then wooden studs with rockwool 40 mm. Then an air gap from 35 mm. Then wooden studs with rockwool 40mm and gypsum 9 mm - green glue - gypsum 12.5 mm.

I am reading the book of Rod Gervais at the moment, but as you can see, I'm still a rookie on this subject.... Your input is really appreciated!!

I would highly suggest reading this one as well: http://www.roletech.net/books/HandbookAcoustics.pdf

Yes, all right, the air is the spring. But what about rockwool etc.? That is also a spring, right? And how does this relates to air? Which spring is better for insulation? Of course there need to be an air gap, because the rockwool is held together by wood studs, and those will resonate.

Just fill the cavity between your sheathing with appropriate insulation. It's that simple.

Maybe this is a solution: put 12.5 mm gypsum on the inner side of the outside wall, to ensure there are no air gaps.

Beefing up your existing outer leaf allows you to have the correct amount of mass (determined by your calculations). During the beef up process, you should apply sealant around everything before and after you affix the gypsum. This will ensure there are no leaks.

Then wooden studs with rockwool 40mm and gypsum 9 mm - green glue - gypsum 12.5 mm.

To save space in your room, I'd suggest building your inner leaf walls and ceiling using John's inside out technique. Greg

Yes, all right, the air is the spring. But what about rockwool etc.? That is also a spring, right?

Nope! Insulation is the damper on the spring, not the spring. Air is the spring.

And how does this relates to air? Which spring is better for insulation? Of course there need to be an air gap, because the rockwool is held together by wood studs, and those will resonate.

The studs don't resonate: the air does. It's the air in the cavity that is responsible for the resonance. The studs are just there to support the leaves. In s fully decoupled wall, the only spring in the MSM equation is the air.

Then wooden studs with rockwool 40 mm. Then an air gap from 35 mm. Then wooden studs with rockwool 40mm

In that case, from the point of view of the calculations, the air gap is 40+35+40 = 105mm. The insulation is IN the air gap: it is part of it. And ideally, the insulation should completely fill the air gap. After all, insulation is mostly air anyway... - Stuart -

Beefing up your existing outer leaf allows you to have the correct amount of mass (determined by your calculations). During the beef up process, you should apply sealant around everything before and after you affix the gypsum. This will ensure there are no leaks.

Will do! And because the existing walls are of course not equal, I was thinking of drilling holes in the gypsum, so I can fill the cavities withm foam or something --> is that an idea?

To save space in your room, I'd suggest building your inner leaf walls and ceiling using John's inside out technique.

That could be a solution indeed, but wouldn't I lose too much isolation?

Nope! Insulation is the damper on the spring, not the spring. Air is the spring.

Thanks for clearing that up! Apparently I understood it completely wrong...

In that case, from the point of view of the calculations, the air gap is 40+35+40 = 105mm. The insulation is IN the air gap: it is part of it. And ideally, the insulation should completely fill the air gap. After all, insulation is mostly air anyway...

All right, and if you put it like this, the air gap will be sufficient? Most people say you need at least 10 cm, right?

Will do! And because the existing walls are of course not equal, I was thinking of drilling holes in the gypsum, so I can fill the cavities withm foam or something --> is that an idea?

Spray foam has no mass and is closed cell. Therefore it does NOTHING acoustically speaking. If one of your existing walls has very little mass compared to the others, add more mass to it specifically (two layers of drywall instead of 1 for example).

That could be a solution indeed, but wouldn't I lose too much isolation?

Not at all. Just make sure the distance between the leaves mass is correct (again, determined with your calculator experiments). The inside out method saves you money on framing material as the wall framing members can hold up your sheathing AND hold your treatment insulation!

All right, and if you put it like this, the air gap will be sufficient? Most people say you need at least 10 cm, right?

Use whatever gap the calculator says offers you your necessary transmission loss. You can estimate the amount of transmission loss you require by deciding what instruments you will be recording. Let's say you will be using acoustic drums. So say you will max out around 115 dBC. Figure out how far your property line is from your exterior wall and use the inverse-square law to see how many dB you will drop in that distance. Find out your area's noise bylaws. Then you will know how much isolation you need your wall system needs to provide. Greg

Thanks!! I will think about this some more... And come back to you guys if I have questions (which I'm sure off I will)

Ideally I want to play there with a band, but the main thing will be recording live drums, guitar, bass. If we can't do this at the same time, I can live with this. And It would be nice to play there with guitar, bass and drums. But I do not mind playing mellow (especially the drums, maybe even buy a jazz kit) --> so if you keep this in mind, any idea how much db we will produce maximum? And the lowest frequencies will be around 60 Hz for the drums and 40 Hz for the bass, I think?

Figure out how far your property line is from your exterior wall and use the inverse-square law to see how many dB you will drop in that distance. Find out your area's noise bylaws. Then you will know how much isolation you need your wall system needs to provide.

The building is at a garden association, so there are no specific noise bylaws, but it has to be quite quiet. But I won't be playing there all day and there won't be people all day, especially not in the evening and off season. I will add a picture where you can see the place from above. As you can see it's around 8m till the footpath and 20m till the nearest house. Of course my neighbours can me closer, when do work in the garden, but that's simple: I won't make loud music during the day when they are working in the garden. I was also thinking about this: it's a small building, so you wan't to lose as less space as possible. Maybe it's an idea adding mass to the outside of the existing walls. OSB (+ something moisture-proof) --> what do you think of this? I'm not sure it's allowed, you need to get permits for everything, but maybe it's worth a try...

You don't intend radiating sound (noise when unwanted, or practice exercises) during the day, but you hope to at night? Virtual instruments are getting better and better. Real instruments will cause hearing damage, especially in small spaces. The performance can often be recorded and revamped later. It is not commonly done, but putting real drums on last or very late in the recording has many many benefits. This is a no brainer. DD

I want to record real instruments, that's the whole intention! But when drums are not realistic, I can live with this. And, as you say, recording drums elsewhere isn't that bad. Can be quite interesting. The outside walls are part brick part wood. So the plan is: 5/8 MDF on outside outer wall + 5/8 on inside of outer wall -- 1x2 wooden studs with rockwool -- 5 cm air gap -- 1x2 wooden studs with rockwool -- 5/8 gypsum + green glue + 1/2 gypsum HVAC above the roof of the inner room --> pointed roof. Is it all right to put MDF on the outside of the outer wall and gypsym on the inside of the outer wall? As regards to possible resonance or so... What I'm going to do now: simulate a few realities and check how much dB they produce --> 1. drum + guitar + bass loud; 2. drum + guitar + mellow; 3. Guitar amp and bass amp + listening to a mix (in turn, not together). Then I'll have to check how much the sounds degrades, from the studio till the point where people can be, with the inverse-square law. Then I can me a few scenario's, with help from the calculator, and see what is possible and realistic.

We want to measure the db output we produce with drums + bass + guitar. What's the best way to do this? I guess if you're in another room, it will be a bit different. And do we need to use a certain microphone setting + a special program? Or is an app on a phone also enough?

Is it all right to put MDF on the outside of the outer wall and gypsym on the inside of the outer wall?

MDF soaks up moisture and basically becomes soggy cardboard. You'll want to use 3/4" OSB for sheathing the outside of your building. Depending on how close it is to neighboring buildings, you might need to use fire treated OSB.

We want to measure the db output we produce with drums + bass + guitar. What's the best way to do this? I guess if you're in another room, it will be a bit different. And do we need to use a certain microphone setting + a special program? Or is an app on a phone also enough?

Buy an SPL meter. I'm sure a cheap (like $80) one from your local music store would be fine. Just don't get a $20 one. And we have yet to find a phone app that is accurate without needing to be calibrated, so don't use a phone app. If you can find a link to one you're considering, please post it here so that we can check if it's decent or not. You'll want to set your SPL meter to SLOW and C WEIGHTING. Greg

You'll want to use 3/4" OSB for sheathing the outside of your building....

Noted!!

Buy an SPL meter. I'm sure a cheap (like $80) one from your local music store would be fine. Just don't get a $20 one. And we have yet to find a phone app that is accurate without needing to be calibrated, so don't use a phone app. If you can find a link to one you're considering, please post it here so that we can check if it's decent or not. You'll want to set your SPL meter to SLOW and C WEIGHTING.

I'm going to search one and I will post the link here. Thanks again!!

Here a few options --> which one is best price/quality? https://www.thomann.de/gb/digital_sound ... ImVuIn0%3D https://www.keymusic.com/item/monacor-s ... vel-meter/ The second one is available at the local music store. Also there is a second hand option --> the ST8850 --> https://www.marktplaats.nl/a/doe-het-ze ... ousPage=lr

The first or third option would work fine. The middle one only has A weighting so do NOT buy that one! Greg

Thanks Greg!! You're very helpful. I will try to buy the second hand one, and otherwise I will purchase the first one. I will post the results here (could take a while)

I've received the decibel meter in fine shape and it seems to work:) What the plan is: set up drums + bass + guitar in a room with similar same dimensions as the future studio (only the testroom will be a bit higher). And put the decibel meter on a few different spots --> in between + near the walls. The highest dB output will be the maintained number. Any tips or remarks?

I've found that a good spot to measure with your meter, is more or less where the drummer's head is... of course, he might object if you remove his head, so try placing the meter a bit higher and a bit forward. If you have drums, bass and electric guitar all going at once, then another good spot is in the middle of an imaginary triangle that joins them. Of course, in a small room, there won't be a lot of difference between measuring that at any point in the room: it's going to be pretty loud everywhere. Just make sure that you have the meter at least three feet away from anything that is loud, and greater distance for bigger things. Also, do make sure your meter is set to "C" weighting and "Slow" response. - Stuart -

Soundman2020 wrote:

I've found that a good spot to measure with your meter, is more or less where the drummer's head is... of course, he might object if you remove his head, so try placing the meter a bit higher and a bit forward. If you have drums, bass and electric guitar all going at once, then another good spot is in the middle of an imaginary triangle that joins them. Of course, in a small room, there won't be a lot of difference between measuring that at any point in the room: it's going to be pretty loud everywhere. Just make sure that you have the meter at least three feet away from anything that is loud, and greater distance for bigger things. Also, do make sure your meter is set to "C" weighting and "Slow" response. - Stuart -

Thanks Stuart!! The drummers head is also exceptionally big, so I'm not sure if I can carry something like that... We will put the meter in the middle of an imaginary triangle. And the meter to "C" + "Slow" And the range on High I guess? 65-130dB?