leafs, bricks and my sanity.. design help needed.

^Tripper^ · Post by **^Tripper^** » Sun Mar 12, 2006 10:34 am

Hi everyone! This is my first post here, thou i've been reading the forum for some time. I'm trying to set up a 5.1 music studio, with an attached vocal booth and a 'live' area. i hope to get suggestions, inputs, critisisms, and a good knock on the head for what i have been working on so far. I've also read the "Dont even think about posting before you read this" post. Please do let me know where i'm going wrong. (i'm sure i am.)

I've been reading up on the suggestions for construction techniques, but I'm not sure quite how to apply it, as i'm on the third floor of a 3 story building, built quite solidly with brick walls and concrete floors and cellings.

i've attached a floorplan. Please excuse how crude it is (not to scale.) I am useless when it comes to graphic software..(it took me 4 hours just to get the letters in..)

All dimensions are in mm/ Length is left to right, Width is Top to bottom.

A - Machine room

B - Control room. (L) 5140 X (W) 4730 X (H) 3000

C - Vocal booth (L) 5080 X (W)(up to 'E') 2720 X (H) 3000

D - Bottom of stairs.

E - Void area. (floor of 'C' ends here)

F - Door (W) 1160

G - 'Live Room' (L) 5160 X (W) 6250 X (H) 4000 'Pitched' celing at highest point

H - Office/Admin

The broken line that seperates 'B' & 'C' is a beam that juts out from the celing, reducing height to 2650mm.

The broken line that seperates 'C' & 'D' is the bottom of a concrete staircase that serves my neighbour upstairs.

The distance between the top edge of 'F' and the bottom of 'D' is 900mm.

'E' is a void area, it has no floor! The floor of area 'C' comes up all the way to where 'E' starts.

'G' has a 'tiles on zinc with wooden support struts' pitched roof.

I'm planning a 'room within a room- floating floors' for the control room (B), and vocal booth (C) as i need pretty good isolation between both these areas and the world at large. i dont want to bug neighbours when i'm mixing loud.. I also have restrictions on removal of windows, so i have to build a wall to cover up the windows in the control room (B). Quite possibly the same treatment for the 'live' area (G).

I have no line of sight between the control room and 'live' area, but i'm fine with that. (Pretty used to it.)

I got a brick wall between Control room (B) and 'live' room (G). The wall is about 11 inches thick. Same for the control room (B) and my neighbour. On the right of the 'live' room (G) is open space. no neighbours.

My questions are;

if i build a 'room with in a room' for the control room, would i not end up with a three leaf setup between it and the 'live' room?

the same problem between the control room and the wall with the windows?

As i might be recording drums in the live room from time to time, should i float the floor?

I would have to angle the walls for the control room and booth. Do i do this with the boundry wall between them or do i build a straight wall bewteen them then angle the interior?

what kind of STC should i be aiming for? My fear is sound getting out of control room and vocal booth.

Ok, i think i'm asking too much here.. my apologies if i'm asking obvious questions. Any suggestions, help, links, comments, indecent offers are mostly glady welcomed.

Thank you for taking the time to read this and putting up with my bad spelling.

Regards;

Trip.

knightfly · Post by **knightfly** » Sun Mar 12, 2006 11:33 pm

My questions are;

if i build a 'room with in a room' for the control room, would i not end up with a three leaf setup between it and the 'live' room?

Depends entirely on your construction; check the reference section or do a search on "terms", it should bring up what a leaf is, what a layer is, etc - basically, pretend you're a sound - try to get from one place to the place you DON'T want sound to go; you should have to travel through some mass, then some air or insulation, then some mass, and that's it. More or less than that and you're in trouble.

the same problem between the control room and the wall with the windows?

Same answer. If you can't use drawing software (I sure hope you're better with MUSIC software :=)) then you'll need to accurately describe every single thing between the two rooms, starting at one side and finishing with the other, well enough so one of us could build your wall from your description.

As i might be recording drums in the live room from time to time, should i float the floor?

Probably; before you float ANY floor though, you need to contact whoever is the engineer of record for your building, and find out EXACTLY what the floors are designed to support. This will be expressed in either Pounds per Square Foot or in Kilograms per Square Meter. Either will do, as long as I know which it is.

I would have to angle the walls for the control room and booth. Do i do this with the boundry wall between them or do i build a straight wall bewteen them then angle the interior?

You can do either, if there's no wall already there. It wastes less floor space to build two parallel frames between the rooms, with those frames NOT parallel to either outer wall.

what kind of STC should i be aiming for? My fear is sound getting out of control room and vocal booth.

STC isn't the number you want; it's a generic, one-number rating that was designed for SPEECH not MUSIC. For MUSIC, you want to compare Transmission Loss values (TL) at each 1/3 octave band from 50 hZ up to at least 4 kHz. For drums, you want all you can get; if you get at least 50 dB TL @ 50 hZ, you're home free more or less - the human ear's threshold of hearing at that frequency is around 55 dB, so that would mean your drums would barely be audible outside when they're 105 dB inside. (This is NOT easy to achieve, BTW)

HTH... Steve

^Tripper^ · Post by **^Tripper^** » Tue Mar 14, 2006 1:08 am

Hi Steve. Thank you for the suggestions and help. I've re-read the 'Terms' post and funny how it seems much clearer to me now.. if i understand it correctly;

The wall between the control room and 'live' room is a 11", cement finished brick wall. Hence, it is one leaf. if i built a frame in the control room side and added wallboards on the control room side only, that would be the second leaf. (Leaving air space between brick wall and new wall.) am i correct to assume this?

If i am, would i need to do the same thing for the 'live' room? Again the brick wall is one leaf and i would get the second leaf from building a frame in the 'live' room and adding wallboards to the 'live' room side only.

on the floor plan, all the vertical lines you see are my current brick walls. these are all the same 11" cemented finished brick design. The top of 'E' and 'live' room 'G', are again the same 11" brick wall. i cannot significantly alter these walls. (no new openings, hence no line of sight...)

the control room 'B', and the vocal booth 'C', are right now one big room, which goes all the way up to 'E'. The top left of the 'live' room 'G', has a 3 step staircase that comes up to a recessed door to the washrooms.

The DB Box you see in the control room is an eletrical distribution box. The size is not to scale (as is the whole image.) the box is 30" long (from the wall with the windows) and 8" deep. i cannot move its location.

i need to create 3 seperate space for Control room 'B', Booth 'C', & 'live' room 'G'. the wall between the control room and booth seems to be pretty strightforward, i need a new wall. it was the walls between the live room and control room that had me stumped.

I hope i wont have a problem building new walls and floating floors. The floors are designed to sustain a superimposed load of 2.5KN/M2. (is this the figure you were asking?) Also, all work will be approved by the authorities before commencing. (Structural, eletrical and urban planning engineers.. Thankfully, they are pretty strict about that around here.) As i'm in a commerical district, the noise codes are pretty lax, but i'm concerned about being the noisy upstairs neighbour that no one likes. More specificly, i'd like to be able to attentuate my levels as much as construction and budget will allow.

I understand i'm asking alot, and many thanks for taking the time to read this post and help out this confused state of mind. Also, my apologies once again for not having better graphics... i promise i'm much better with a DAW!!

Regards;
Trip

knightfly · Post by **knightfly** » Tue Mar 14, 2006 9:48 pm

If you put another leaf on the CR side of that brick wall, you do NOT want to put a THIRD leaf on the LIVE room side or you will have a 3-leaf wall. YOu can add acoustic treatments, but NOT another airtight mass. The way to figure this is: in ANY direction sound wants to travel, you want Mass-Air-Mass. Period. not more, not less. The "air" should be actually fiberglass or rockwool insulation, 48 kG/m^3 OR LESS for inside the walls.

Floor loading - I deal with metric stuff quite a bit, but this 2.5KN/M2 has me stumped; what is the "N" in that expression?

I'm glad you're better with a DAW than with a "DRAW"...

^Tripper^ · Post by **^Tripper^** » Wed Mar 15, 2006 4:41 am

knightfly wrote:If you put another leaf on the CR side of that brick wall, you do NOT want to put a THIRD leaf on the LIVE room side or you will have a 3-leaf wall. YOu can add acoustic treatments, but NOT another airtight mass. The way to figure this is: in ANY direction sound wants to travel, you want Mass-Air-Mass. Period. not more, not less. The "air" should be actually fiberglass or rockwool insulation, 48 kG/m^3 OR LESS for inside the walls.:

i hear you.

knightfly wrote:Floor loading - I deal with metric stuff quite a bit, but this 2.5KN/M2 has me stumped; what is the "N" in that expression? .:

N= newtons. i suppose its kilonewtons?

knightfly wrote:I'm glad you're better with a DAW than with a "DRAW"... :wink.:

i've been using paper, a pencil and sometimes a ruler. i also keep an old 1/4" tape deck .

Thank you!

knightfly · Post by **knightfly** » Wed Mar 15, 2006 7:50 am

According to this calculator

http://www.rightonscales.com/web/converter/

2500 newtons would equal 277 kG; man, that's one mean mother of a floor

and if you take the "K" away, it's not even minimum for WALKING on it. Must be something else...

^Tripper^ · Post by **^Tripper^** » Wed Mar 15, 2006 11:19 am

knightfly wrote:According to this calculator

http://www.rightonscales.com/web/converter/

2500 newtons would equal 277 kG; man, that's one mean mother of a floor and if you take the "K" away, it's not even minimum for WALKING on it. Must be something else...

sounds massive dont it? i'll confirm this with the structural guy, but thats what i've been told, kilonewtons.. i suppose it could be right, its a reinforced concrete floor...and it looks mean.

^Tripper^ · Post by **^Tripper^** » Thu Mar 23, 2006 1:22 am

Hi steve. sorry about the delay, but i finally got my structrual engineer to confirm it. its is kilonewtons. so your figure is about right.

quite a floor.

knightfly · Post by **knightfly** » Thu Mar 23, 2006 7:40 am

Actually, I'd read the calculator page wrong; that works out to about 56 PSF, which isn't all that hefty. Can you confirm that your existing brick walls are supported by other similar walls in each floor under yours? I need to know that your floor's support capability isn't already being used.

Also, if your engineer can tell you what your existing floor weighs ALREADY, that will help figure out how much MORE weight that floor can take and still be safe... Steve

^Tripper^ · Post by **^Tripper^** » Thu Mar 23, 2006 8:31 pm

Hi steve.

i can confirm that there are similar walls under. As for the weight, the figure of 2.5 KN is the maximum allowed weight, ie, the floors are designed to hold a maximium superimposed weight of 2.5 KN. This is stated clearly on a 'load bearing' chart thats displayed prominantly at the entrance.

I dont have the current weight of the floor, but i guess it means that i cant exceed the 2.5KN regardless.

According to this; http://www.convert-me.com/en/convert/weight , this works out to about 562 pounds? (1 KN=1000N). Quite different from your figure. i must be missing something..

Trip.

knightfly · Post by **knightfly** » Thu Mar 23, 2006 10:06 pm

Yeah, you're missing the fact that those #'s are for square METERS; divide by 3.28 SQUARED to get pounds per square FOOT and your calculations should come out like mine... Steve

(or, if you're more used to metric you can just keep it at kH/m^2) - the main thing is you don't put more weight on the floor than it is rated for...

^Tripper^ · Post by **^Tripper^** » Fri Mar 24, 2006 12:50 am

I knew i missed something..

it works out to

2.5 kilonewton/meter^2 = 254.93 kilogram-force/meter^2

Not even mean enuff to date my aunt. just gotta make sure i dont over exceed it, like you said.

What do you think? is floating still an option with these numbers?
.

SonicClang · Post by **SonicClang** » Fri Mar 24, 2006 1:14 am

This is actually quite an interesting topic. I've recently started to think about (yeah, a little late after 4 years) how much weight the ceiling I designed is adding to the floor joists. They are engineered joists, which helps, and I have added walls to split up the spans, and after 4 years of having part of the ceiling complete I haven't seen any sagging or cracks in the upstairs walls. I actually left a gap above the walls I did build in my studio because I didn't want sound to transfer through the structure to the upstairs, and after 4 years that gap is still there. And by "gap", I mean about 1/8"... that gap hasn't closed in 4 years of having part of the ceiling up. I am adding a little more weight than two layers of drywall, so it's just something I've been thinking about, even though I'm sure I'm safe.

knightfly · Post by **knightfly** » Fri Mar 24, 2006 11:13 am

Why do you want to mix "loud", and how loud are you talking about?

Since you already have brick walls that undoubtedly connect solidly to the rest of the building, that needs to be considered when deciding how to build your inner structure; questions like "which room will be the loudest", "how much isolation do I need between rooms", etc, will need answers before you decide which parts of your building can be primary walls and which ones need to be decoupled the most.

4" of concrete floated on your floor will come within 6 pounds of maximum allowable loading, with no walls or ceiling figured into that; less thickness can work, but will need a wider air space between original and floated floor to help MSM stay as low as possible -

It's starting to look like you need to consider inner frames NOT floated on you floor, and a suspended ceiling NOT supported by your floated floor, in order to make this work; this will entail using resilient mounting methods for all your inner walls, and this includes whichever room you decide is your "loud" room - you may have to end up with a couple of 3-leaf walls in order to isolate yourself from the neighbors, due to flanking paths along those brick walls;

This can work, the brick walls are pretty massive - but it will likely reduce the LF TL somewhat, possibly making it necessary to "cut and try" to get the drum sounds you want. Life is a compromise... Steve

whatalob · Post by **whatalob** » Tue Mar 28, 2006 10:48 pm

knightfly wrote: The way to figure this is: in ANY direction sound wants to travel, you want Mass-Air-Mass. Period. not more, not less. The "air" should be actually fiberglass or rockwool insulation, 48 kG/m^3 OR LESS for inside the walls.

Sorry to jump in and go off topic, but reading this quote by Steve made me question my understanding of the most basic concepts regarding walls (having read the ref section multiple times). I thought that a single leaf includes the actual insulation layer, so a typical inner leaf would be: gypsum+ gypsum+ rockwool all attached to each other which is the separated by an actual air gap from the outer wall which typically is concrete and bricks and acts as the second layer.

Can someone enlighten me?

Also, according to the ‘more mass is better’ principle why is the 48kg/m^3 the maximum when you can get for e.g. the 150kg one?

thx