Improving soundproofing for a brickwall

[memocn59]

Hi, I´m building my recording studio and have two rooms (live and control rooms) that are divided by a single brick wall. This brickwall is 15 cm thick and I´m planning to get a 1m*1.5m acoustic window on it so I wan´t two things... I´m considering building a extra layer wall in order to improve soundroofing a little bit more and also in order to have a bigger surface in which the acoustic window will have a better chance to stop sound.

However.. What would you say is the best way to improve the soundproofing of this brickwall. I´m planning to record drums, even bass.

I would like to know your general suggestions but as a background.. Im planing on biulding a wood stud decouple from the brickwall ... Brickwall would be leaf 1 and planning to have durock as my second leaf (which is a concrete board 23.3 kg/m density) with a 5 to 10 cm of air space filled with mineral wool.

[Gregwor]

Welcome to the forum memocn59 (whatever your real name is)!

First off, it's very important to forum members that you completely fill out your profile. So right now, please go and do that.

I´m building my recording studio and have two rooms (live and control rooms) that are divided by a single brick wall. This brickwall is 15 cm thick and I´m planning to get a 1m*1.5m acoustic window

The brickwall is great. But, brick is porous, so you will have to seal it.

For your window, make sure it matches the surface density that your isolation requires. Also, make sure it's single pane laminated.

I´m considering building a extra layer wall in order to improve soundroofing a little bit more and also in order to have a bigger surface in which the acoustic window will have a better chance to stop sound.

One of your presumptions is correct, the other is incorrect.

Adding a second leaf (de-coupled) will drastically improve your isolation. Having more surface area of window won't improve your isolation. As long as your window is properly installed and has the correct surface density, it will not change anything.

Are you implying that the window in your second leaf will be larger than the window in your first leaf? That's a great idea to improve viewing angle.

However.. What would you say is the best way to improve the soundproofing of this brickwall. I´m planning to record drums, even bass.

Well, presuming the brick wall is structural and is the separating wall between your CR and LR, then it has to count as an outer leaf. That means that unless you sacrifice lower frequency isolation and go with a three leaf system, your best bet is to seal the brick and then build another de-coupled room (that means ceiling too) in your live room.

If you want to go the three leaf route, you would just have to build another de-coupled room in your control room as well.

I would like to know your general suggestions but as a background.. Im planing on biulding a wood stud decouple from the brickwall ... Brickwall would be leaf 1 and planning to have durock as my second leaf (which is a concrete board 23.3 kg/m density) with a 5 to 10 cm of air space filled with mineral wool.

Have you done the calculations to determine exactly how much surface density you need on your leaves to achieve the necessary transmission loss? Have you taken SPL measurements to figure out how much isolation you require to meet bylaws and/or your personal needs (to keep outside noise from ruining your recordings)?

Hi, I´m building my recording studio

We strongly suggest that you DESIGN your studio 100% before you build anything. Download and draw it all up in as much detail as possible using SketchUp Make (just google "old sketchup download" to find the download links). Post your .skp files for us to review and help answer any questions you may have. As you probably have already seen, the forum is full of contributing members willing to help you out for free! Also, the search feature on the forum is a great resource.

Greg

[memocn59]

Welcome to the forum memocn59 (whatever your real name is)!

Haha, the name is Memo. Thanks for taking the time for that useful answer

First off, it's very important to forum members that you completely fill out your profile. So right now, please go and do that.

Done =)

Adding a second leaf (de-coupled) will drastically improve your isolation. Having more surface area of window won't improve your isolation. As long as your window is properly installed and has the correct surface density, it will not change anything.

I actually have someone to build and install the window... I was thinking about decoupling the second leaf in order to improve soundproofing of the brickwall a little bit just in case (yes, I didn´t take measurements before building =( just discovered your forum today) but I do wonder:
Is there any case in decoupling this two leafs when the window will sit on top of both leafs somehow coupling them again?

Are you implying that the window in your second leaf will be larger than the window in your first leaf? That's a great idea to improve viewing angle.

Are you talking about an acoustic window that is decoupled? Can you point to some video or text I can read or watch in order to learn more? And yes... my brickwall is like 15 cms thick and the second leaf im planing to be like 5 cm thick and air space between the two, 10 cms

That's a great idea to improve viewing angle.

What do you mean?

Have you done the calculations to determine exactly how much surface density you need on your leaves to achieve the necessary transmission loss? Have you taken SPL measurements to figure out how much isolation you require to meet bylaws and/or your personal needs (to keep outside noise from ruining your recordings)?

No, I didn´t the only thing I did was a speech test from one side of the wall to the other (we didn´t hear a thing) when the brickwall dind´t have the whole for the acoustic window... and also I ran the monitors loud (I think louder than drums) and I heard the music lightly... But no, =( no numbers

I have two adyacent rooms, like a big rectangle divided by the 15 cm brickwall... I want to isolate both rooms... So I can hear through the speakers in the CR while recording drums at the other side of the window. Since I heard a little of the music when I ran my non cientifically test haha I decided that an extra layer for that wall would be a good idea.

By now and to the extent that I undestand... Is not so good idea to have three leafs, so, I believe the brickwall would be leaf 1. Then I´m planning to have another leaf (may plywood, mdf, drywall, durock, I don´t know, which will you suggest for better soundproof?) separated by 10 cm of air, some of it with insulation. This new leaf would be attached to the floor and ceiling but decoupled from the brickwall...

Honestly, I can´t say how much TLC I need =( but could you advice something in order to improve soundproof of brickwall with acoustic w indow? The hole for the acoustic window is done... it´s 1*1.5m

Thanks for your kind help

[Gregwor]

Hi Memo! Cool name! Thanks for filling out your profile.

Is there any case in decoupling this two leafs when the window will sit on top of both leafs somehow coupling them again?

Each leaf will need it's own window in it. You cannot let the inner and outer leaves touch one another. No flanking anywhere except the concrete floor!

Are you talking about an acoustic window that is decoupled?

I'm talking about normal windows (laminated glass) that you use in any studio or acoustic situation.

Can you point to some video or text I can read or watch in order to learn more?

Try using the search function on the forum here and look up:
BRAUS window

That will point you to some great information!

What do you mean?

If your control room inner leaf wall window is smaller than your live room inner leaf window, it will allow you to see more of your live room.

No, I didn´t the only thing I did was a speech test from one side of the wall to the other (we didn´t hear a thing) when the brickwall dind´t have the whole for the acoustic window... and also I ran the monitors loud (I think louder than drums) and I heard the music lightly... But no, =( no numbers

Set up a real acoustic drum kit and hit the hell out of it. That and if you can, have a full band playing in there full volume. That's the way you should test.

By now and to the extent that I undestand... Is not so good idea to have three leafs, so, I believe the brickwall would be leaf 1. Then I´m planning to have another leaf (may plywood, mdf, drywall, durock, I don´t know, which will you suggest for better soundproof?) separated by 10 cm of air, some of it with insulation. This new leaf would be attached to the floor and ceiling but decoupled from the brickwall...

Since you already have the brick separation wall, you need to decide which room (or maybe both rooms) need isolation. If your control room is quiet enough for your needs, then I'd suggest building a FULLY de-coupled inner leaf in your live room. That means a ceiling sitting on walls. Touching no where except the floor where you walls sit. If it touches anywhere else, you've compromised the entire system and it is basically as good now as it will be in the end. So, you've expressed that your isolation is not good enough. Your next step is the fully de-coupled room in a room construction.

Honestly, I can´t say how much TLC I need =( but could you advice something in order to improve soundproof of brickwall with acoustic window? The hole for the acoustic window is done... it´s 1*1.5m

Do you not have any neighbors nearby? Is your property line so far away that your sound level will naturally be quiet enough to meet bylaw restrictions?
Basically, you need to figure out at what distance you legally need to be a certain volume. From there, play your drums and/or have a band jam full volume in the room and use a decent quality (not a phone app!) SPL meter set to SLOW and C WEIGHTED. Write down that number. Go to your property line and measure it with the band playing the same volume.. maybe get them to loop a chorus over and over. If the measured SPL at your property line is below the bylaw number, you're good to go (legally). If not, subract your bylaw SPL from the SPL measured inside your room with the band playing. That the the amount of isolation you need your room to provide.

The other number that matters is how well you want your rooms to keep out sounds like traffic, rain, lawnmowers, etc. Ideally, you don't want any of that to get into your microphones or to distract your mixing.

Regarding disturbing sounds, HVAC is something you really need to consider and design properly. You need your rooms to be comfortable and safe. Also, you need your system to move air at a slow enough rate with minimal turbulence so that delicate recordings like finger picked acoustic guitars or vocals aren't ruined with wind noise! Have you designed any HVAC for your rooms yet?

Greg