Studio Construction and soundproofing

[LeGrizz]

Hi everyone,

This is my first post here - and this is a long one ! I hope that my profile is good and that I respect this forum’s rules.

First, I wanted to say that I've been doin' researches on studio design for months, and I just discovered this forum which is a true gold mine ! So very much thanks to every contributor and keep up the good work, this is great !
Sorry in advance for my English (I’m French !)

Okay, so now I’m gonna get to the heart of the subject.

With three friends (we're three sound engineers and one musician), we plan to build a studio in order to play, record and mix music in a professional way.
We’ll have drums, bass, electric guitars, piano, B3 organ, vocals, etc... (yeah, we’re gonna make a lot of noise !). Something like 120 dB (A) I assume, right ? So we need a good soundproofing !

I haven't done any measurement during the night but I think something like 50 Db (A) is pretty good (I guess). We're in the underground of a really big building (so normally we’ll not received complains from neighbours). No problem neither with the first floor: we’re separated by a really heavy concrete floor (our ceiling).

Our main problem is our neighbours who live in the underground. The underground is in fact a long corridor with boxes to rent on the sides. There are several people who plan to use their space for music: there's a music school, a rehearsal room and one or two other recording studios (but not really professional ones). This is why I think we don't have to be so silent. And I can't evaluate how loud they could be because everything is under construction.

Our room dimensions are: 787 x 614 x 250 cm (I hope meters will be fine for you !). I know this is a low ceiling but we can't do anything about it...

Each box is separated by a single BA13 drywall, so obviously it's not enough. For now, we don't have direct neighbours as the boxes aside us (right and left) are used for stocking but we'll probably have in the future. The back of room is made of a really heavy and thick concrete wall and there's nobody behind and the front is also a single drywall partition which gives on the corridor (maybe 3 meters of width) and after the corridor, other neighbours.
So to sum up, right now we have:

Left side, front side, right side: single drywall partition
Back side: heavy concrete wall
Floor: heavy concrete (nobody below)
Ceiling: heavy concrete

SO, for soundproofing, we plan to put: 3 layers of acoustic drywall (these are the blue ones with a density of something like 930 kg/cubic meters), 10cm metal studs (i heard it's better than wood for soundproofing) filled with 10 cm of fiberglass, then 4,5cm of naked fiberglass to fill the gap, then another 10cm metal stud filled with fiberglass and then 3 layers of acoustic drywall.

We have second thought about putting Fermacell (density: 1200 kg/cubic meters) instead of acoustic drywall but it's a lot more expensive ! Something like 1000 euros (1100 $) more than with the acoustic drywall.

So here's my question (the first of many !): Does this plan seem good enough to you for soundproofing a room with drums ? Do we have to change for the Fermacell ?
If no, what are we doin' wrong ? Is it ok that the interior and the exterior partition have the same thickness ?
Of course with everything caulked etc... But no green glue, I heard it's not necessary. I also heard it's better to put the drywall on a 1cm plywood to lower vibrations between the floor and the walls. Can you confirm that ?

Also, as we have the back wall, floor and ceiling built with heavy concrete, we plan to put a single partition of drywall, maybe MDF, or even nothing as we're gonna put some treatment after. For the floor, not decided yet but probably some laminate or linoleum. Is it ok ? What are your advices ?

As you can see with the sketchup screenshot, we want to do a control room (good ratio, dimensions meet Bonello) and a live room, separated with the exact same set up (3 layers of acoustic drywall, 25cm of fiberglass and then 3 layers of acoustic drywall). Is it also enough in this case ?

By the way, to understand my sketchup, the pink is insulation and the orange is for the treatment (not really precise but it's there to see what space it could take). And the other little room is a little storage room for mic stands and everything.

I got plenty of other questions about treatment, electricity, HVAC etc... but I keep it for later.

I know this is holidays period so I don't expect a lot of quick answers but I gotta try !

I really hope someone will help me ! Any help will be very much appreciated ! And thank you so much for reading this long post !

Thanks,

Hugo.

[LeGrizz]

Anyone ??

After reading more posts on this forum (this is my main hobby since the last three days...), especially from Stuart, I understood that it's really difficult to get more than 70 dB of isolation and even if I haven't done some measurements yet (I'm gonna order a SPL meter pretty soon), it seems pretty obvious that if we got direct neighbours on sides of the room (i repeat that for now, it's not the case), we'll need at least transmission loss of 65-70 Db.

Of course, I know what you're gonna tell me: "Measure, measure, measure ! We can't work with guesses ! ". Yeah, I know, and I sure will do some measurements. You convinced me ! But still, I need to know if in the worst scenario, we could achieve 70 dB of isolation and how much would it cost.
I've tried hard but I haven't managed to find how to get such isolation. So anyone can help me on how much dB of isolation a 3 layers BA13 acoustic drywall + 25 cm (10 ") of fiberglass + 3 layers BA13 acoustic drywall represents ?
And if it's not enough, how to achieve 70 dB ?

More bonus questions:

- I don't understand how to determine thickness of the interior/exterior partitions. Do they always have to be the same, or can it be different ?

- If I have a direct neighbour on the right wall and a other neighbour at 5 meters from our front wall, can I put a heavy layer of drywall (so more isolation) on the right side and a less heavy partition on the front wall ? Similarly, as the control room will be less loud than the live room, can we have less isolation on the left wall ?

- Would a drum riser help in our case (heavy concrete floor) ?

- What do you advice for the ceiling ? Do we have to treat the whole ceiling or can we just put long cloud panels ? How thickness should the panels be ?

I stop here because I got too many questions !

Anyway, I'll post some photos of the room and update my sketchup so you'll see more clearly what I'm talking about.

Thank you !

[bigsister]

Hello Hugo,

Looks like a fun and exciting project. I'm no expert but I'll get the conversation started at least.

I'm sure you've seen the 2 leaf MAM system being talked about on the forum. Make sure you're consistent with this in the whole build. It's great that the walls are done this way but what about the ceiling and doors too? Even thick concrete will transfer sound waves. Putting an air gap between 2 pieces of mass is the only way to reasonable get high levels of isolation. The concrete ceiling will be a flanking path between your rooms and into the first floor above you, especially for low frequencies.

SO, for soundproofing, we plan to put: 3 layers of acoustic drywall (these are the blue ones with a density of something like 930 kg/cubic meters)

3 layers sounds like a lot, but like you said, best take some measurements. Your doors and ceiling will need to match whatever your walls are, otherwise they'll the weak link.

10cm metal studs (i heard it's better than wood for soundproofing) filled with 10 cm of fiberglass

I've heard the opposite, metal walls aren't rigid enough. Also wood is a little more forgiving if you make a mistake or need to change something. If you're doing a MAM system (and you should) I've only ever seen wood framed walls being used.

We have second thought about putting Fermacell (density: 1200 kg/cubic meters) instead of acoustic drywall but it's a lot more expensive ! Something like 1000 euros (1100 $) more than with the acoustic drywall.

As Stuart says, sound waves don't care about the price tag. It's just a matter of mass. Don't get caught up in the marketing, look at the spec sheet. Drywall is used for a reason, cheap mass. Even special acoustic rated drywall is overkill if the price is more and the mass isn't.

Of course with everything caulked etc... But no green glue, I heard it's not necessary. I also heard it's better to put the drywall on a 1cm plywood to lower vibrations between the floor and the walls. Can you confirm that ?

I've probably mis understood but I would attach drywall with acrylic stud adhesive or liquid nails, not caulk. I'd use caulk to fill in the gaps after each layer. I'd consider green glue between drywall though if I were you. You're limited in space and if you want serious isolation it sounds exactly like the product you need. Except for the price Do you mean 10mm ply on the floor and then the drywall resting on that, attached to the wall? Or is the plywood for the wall?

Also, as we have the back wall, floor and ceiling built with heavy concrete, we plan to put a single partition of drywall, maybe MDF, or even nothing as we're gonna put some treatment after. For the floor, not decided yet but probably some laminate or linoleum. Is it ok ? What are your advices ?

I'd say concrete wouldn't be great for reflections but I guess with enough treatment it could be ok. But more importantly, I'd be building another wall regardless of the concrete wall to get an air gap. You might be under estimating just how hard it is to stop low frequencies. I'd put laminate wood flooring at a minimum, preferably solid wood. That's more for aesthetics and acoustics though, not sound proofing. But there's no one below you so you should be ok there, right?

By the way, to understand my sketchup, the pink is insulation and the orange is for the treatment (not really precise but it's there to see what space it could take). And the other little room is a little storage room for mic stands and everything.

Where is the door to get into the room? Also to get into the store room? I think you'd need a layer of insulation across the back of the wall behind your speakers, even just to help stop that room becoming a resonating chamber.

I got plenty of other questions about treatment, electricity, HVAC etc... but I keep it for later.

HVAC will be the big one and you need to think of it early, not something you try to add at the end.

- I don't understand how to determine thickness of the interior/exterior partitions. Do they always have to be the same, or can it be different ?
- If I have a direct neighbour on the right wall and a other neighbour at 5 meters from our front wall, can I put a heavy layer of drywall (so more isolation) on the right side and a less heavy partition on the front wall ? Similarly, as the control room will be less loud than the live room, can we have less isolation on the left wall ?

If I understand your question right, it's not so much the thickness but the mass. Or are you asking about changing the mass from wall to wall to allow different levels of isolation depending on what is on the other side of the wall? For the price of drywall I'd say keep it consistent although if you have varying masses on the other side (the concrete wall) it might change things. Hard to calculate though.

- Would a drum riser help in our case (heavy concrete floor) ?

Do you mean help with sound below? If there's nobody below then it's not an issue. There would be some flanking into rooms to the side though. I got around this by having separated slabs, not physically connected.

- What do you advice for the ceiling ? Do we have to treat the whole ceiling or can we just put long cloud panels ? How thickness should the panels be ?

I think considering your limited height, you should do an inside out ceiling. Search it on this site. Acoustic cloud panels will only help treat the room acoustically, it won't help stop the sound getting out of the room much.

I know you pos there to get feedback but I hope that's not too negative! You're off to a good start with some good room dimensions and sounds like you're ready to take on advice. I've seen people trying to get a studio going in a much smaller space.

Mark

[LeGrizz]

Hi Mark !

Thank you so much for starting the conversation ! I was feeling lonely on this forum ! And sorry for my late reply, I've been busy these days.

It's great that the walls are done this way but what about the ceiling and doors too?

I really think this is ok for the ceiling. They're quiet upstairs, it's just a space to recharge scooters. And the concrete is really thick. I don't plan to put anything on ceiling except treatment.

About the doors, I'm still not sure what material should I use but I was thinking using an existing door (I hope I could find some for free) and gluing with green glue some MDF on it to put more weight and fit the walls. Then an air space of 2 cm filled with backer rod like I've seen it in a thread of this forum, and then an other door with MDF like the first one. You can see it in the Sketchup screenshot.

I've heard the opposite, metal walls aren't rigid enough. Also wood is a little more forgiving if you make a mistake or need to change something. If you're doing a MAM system (and you should) I've only ever seen wood framed walls being used.

I attached a screenshot of an article written by the studio designer John Brandt where he talks about steel studs (full article here: https://www.jhbrandt.net/wp-content/upl ... eed.pdf%20 ). But I agree with you that wood is a more forgiving material, I'll maybe consider using woods instead of steel studs for that reason.

As Stuart says, sound waves don't care about the price tag. It's just a matter of mass. Don't get caught up in the marketing, look at the spec sheet. Drywall is used for a reason, cheap mass. Even special acoustic rated drywall is overkill if the price is more and the mass isn't.

Yeah, I was already aware of that, this is why I specified the density. The density of Fermacell is about 1200 kg/cubic meters and the price per square meter is proportional to the density of acoustic drywall (density 929 kg/cubic meter). So it's not a marketing product, it's actually used in many studios but I wonder if I need such mass.

Where is the door to get into the room? Also to get into the store room? I think you'd need a layer of insulation across the back of the wall behind your speakers, even just to help stop that room becoming a resonating chamber.

I've re-updated the sketchup, I forgot the store room door in the last one. The doors are represented in brown with an arc representing the opening of the door.
We talked a few days ago with the owner of the room and he wants at least one door of 140cm (in two pieces) so we had to review our plans. Can a door in two pieces work (like I've done it in the sketchup screenshot) ? The main door is 90cm of width and the other part is 50cm. It will stay closed most part of the time but in case we need to bring large stuff, we can open it.

The big question I have now is: do I really need insulation behind the wall of the control room ? Because I don't care if the storing room is a resonating chamber since it's only used to stock. I just want good isolation between the live room and the control room. If I put some insulation on this wall, the storing room will be too small and impossible to make since I wont have enough width to put a door (I hope it's understandable...). So I would like to keep it like this if possible. Can somebody confirm me if this way of doing it is correct ?

I'd say concrete wouldn't be great for reflections but I guess with enough treatment it could be ok. But more importantly, I'd be building another wall regardless of the concrete wall to get an air gap. You might be under estimating just how hard it is to stop low frequencies. I'd put laminate wood flooring at a minimum, preferably solid wood. That's more for aesthetics and acoustics though, not sound proofing. But there's no one below you so you should be ok there, right?

No, I think it's really ok to leave the concrete wall like this. It is a really thick one and there's no one behind it.
Concerning the floor, we chose to put the cheapest solid wood, it will be more aesthetic as you say. And right, there's no one below so it's also ok.

HVAC will be the big one and you need to think of it early, not something you try to add at the end.

The owner wants to put ventilation for every room, he's now searching for someone to install it. So I will talk with the person he'll choose to see what we can do. But this is only for ventilation so I dont know what to do with the AC for now. Do we really need it ?
And do we need ventilation for the storing room ?

I think considering your limited height, you should do an inside out ceiling. Search it on this site. Acoustic cloud panels will only help treat the room acoustically, it won't help stop the sound getting out of the room much.

As I've already said, I think the ceiling is enough for isolation and I only plan to put treatment directly on the whole surface (like an inside out ceiling but without the mass).

Last time we went to the room, there was a metal drummer who was playing in his room and this was really loud in the corridor ! I asked him to see what he did in his room to soundproof it and it was nearly nothing. So fortunately, he's a little away from us and I think we can achieve enough isolation to not hear him once the room finished. I also talked with the owner and he promised me we'll have only storage aside us, so we won't have direct neighbours. That's a good point for us in terms of isolation !

I ordered a SPL meter. Once I'll receive it, I will do some tests and let you know.

If I understand your question right, it's not so much the thickness but the mass. Or are you asking about changing the mass from wall to wall to allow different levels of isolation depending on what is on the other side of the wall? For the price of drywall I'd say keep it consistent although if you have varying masses on the other side (the concrete wall) it might change things. Hard to calculate though.

Yes, you understood my second question. But I think I will keep every wall the same mass as you've said.

Concerning the first question, let me explain myself:

I've heard that having different materials of different density and different thickness within the same leaf is better for isolation rather than 3 layers of the same material and same thickness.

Example: Considering two walls having the same mass (I know they don't have in reality but imagine they have). One has 3 layers of drywall and the other is made of one layer of drywall + one layer of MDF + one layer of Fermacell. Is there one better than the other (I repeat: imagine they have the same mass) ?

Thank you for your answers !