one car garage live room design - please comment

hi, after recently realising that i can utillise the small bedroom as my CR i have been trying to design part of my garage as a live room. I have attached a skp file of the design based on john's inside out wall design as used on spark one container studio. i am new to skp so i have just done something basic to illustrate my plan. location: the garage is attached one one side to my house ass sown with the other side backing on to a neighbours garden. the front leads to the drive though a small section that i am reseving for my motorcycle and the rear leads to the garden. walls: all stud work walls will be isolated from the floor and walls via rubber. as above the will be of inside out design using rockwool slab loft insulation (about 100mm thick). frame for walls will be constructed from timber. the side backing on to the house will have absortion panels fixed to the walls (shown in blue). the side backing onto the neighbours house will be angled and insulated (i have yet to look how these are constructed). the wall with the door is still to be developed. the side where the garage door would be is partitioned with an inside out wall then angled. CR: the Control room is on the house side wall on the first floor - to be designed. Uses: i would love to be able to use a analoge drum kit in here with minimum distruption to my neighbours. I do have a digital drumkit and probably will use that alot anyway. apart from that the only other loud items would be vocals. obviously as i plan to record in there i need to eliminate noise from outside. ceiling: this is still being considered - i have a typical light weight frame and roof tiles. obviously this is going to be a problem but i am also having to consider the fact that it cannot support any real weight. currently i am considering shoving as much insulation up there that i can and stretching open weave material accross the beams to hold it up - any ideas would be appreciated. i think i have mentioned everything - thanks for viewing, if anyone has any questions i will try to answer as best i can.

Hi Leon. Welcome!

Uses: i would love to be able to use a analoge drum kit in here with minimum distruption to my neighbours.

Looking at your design, that's not going to happen! An acoustic drum kit can easily put out 115 dB. There is no way that a single leaf wall is going to stop that! OK, so it is brick in some places, and that helps a bit, but it is still single leaf, and you show that you are replacing the garage door with a single sheet of drywall?

ceiling: this is still being considered - i have a typical light weight frame and roof tiles. obviously this is going to be a problem but i am also having to consider the fact that it cannot support any real weight

If you cannot support any real weight, then you cannot get any real isolation. Unfortunately, the only way to stop sound is to put mass in the way. Lots of it. There just isn't any other way (unless you can figure how to surround your house with a vacuum...). Mass is number one, decoupling is number two. To isolate, you need to have two leaves in your wall, they each need lots of mass in them, and they need to be decoupled from each other. "Decoupled" meaning "not touching, not connected mechanically, not even by a single nail, and with at least a few inches of air gap between them". What you show on your diagram does not have any of that.

currently i am considering shoving as much insulation up there that i can and stretching open weave material accross the beams to hold it up

That would help the room to sound better, from an acoustical treatment point of view, but it wont do anything at all for your isolation, unfortunately.

any ideas would be appreciated.

A 2-leaf decoupled MSM wall is the only way to isolate acoustic drums at reasonable cost. Since you can't put any extra mass on the existing roof, then that will have to be your outer leaf, and you can compensate somewhat by putting more mass on your inner leaf ceiling, and using a larger air gap than you would have used otherwise. - Stuart -

Stuart, you say that you need an air gap of at least a few inches, which i understand. What I dont get, is how inside out walls/ceiling is supposed to save space? Lets say with normal construction I am leaving the recommended minimum of 4" gap between leaves, then after drywall of say 1", my acoustic treatment protrudes a further 4" totalling 9" from my outer leaf. Now if I were to construct using the inside out method, my inner leaf would be placed 4" away from the outer leaf, then 1" of drywall, then 4" of stud which i can fill with acoustic treatment. This also puts the innermost surface 9" away from the outer leaf only this time it is the whole wall/ceiling that is this close rather than just the areas that would have had treatment using the regular construction method? I may be being really stupid, and i really want to understand this as i am going to be using a room just 8' wide and could do with some extra space, but i cannot see how inside out saves any space?

thanks for the comments. After reviewing them and some information i have re-adjusted the design and have attached a pdf. the ceiling, not shown on the diagram will be constructed in the same manor and fixed to the walls creating a cap around the box isolating it from the garage walls. the small door into the garage will have a panel adding to it to try to beef up its insulation. The door into the live area will be made in a simular fashion to the walls. the side facing the large garage door (storage area side) can have an extra leaf added if required. right, please comment and below i have a few questions: 1) the gap on the left hand side of the garage, due to the shape, has a bigger air gap in some areas. after reading some information within the reference area, i understand that different air gaps have different effects. do i need to add panels or insulation against the wall in the deeper areas to standardise this depth? 2) the ceiling joists for the garage are about 1 to 1/2 inch above the ceiling of the live area and as stated before will no hold alot of weight. To incorporated the two leaf design in the ceiling, if i took my original idea of fixing some material across the beams (something closed weave and dense, take carpet as an example) and stuck some insulation on the top of it, would it act as a second leaf?? i think thats all for the mo, i'm sure i'll think of something else :D

i was looking for something more constructive to be honest :horse:

These are some pictures before pictures of the space i have to work with. As you can see from one of the pictures, i have to incorporate a small space at the front for my bike.

My control room will be in my spare bedroom........well bedroom said loosely, its more of a shoe box than a bedroom but its the only space i have available. i will be bringing a multicore cable through the wall to drop to the box for my connections. I will ofcourse be treating this room as best i can at some point. :shock:

Start of wall panels, to be of an inside out design decoupled as much as possible from the exterior walls e.t.c

leon.payne wrote:

thanks for the comments. After reviewing them and some information i have re-adjusted the design and have attached a pdf. the ceiling, not shown on the diagram will be constructed in the same manor and fixed to the walls creating a cap around the box isolating it from the garage walls. the small door into the garage will have a panel adding to it to try to beef up its insulation. The door into the live area will be made in a simular fashion to the walls. the side facing the large garage door (storage area side) can have an extra leaf added if required. right, please comment and below i have a few questions: 1) the gap on the left hand side of the garage, due to the shape, has a bigger air gap in some areas. after reading some information within the reference area, i understand that different air gaps have different effects. do i need to add panels or insulation against the wall in the deeper areas to standardise this depth? 2) the ceiling joists for the garage are about 1 to 1/2 inch above the ceiling of the live area and as stated before will no hold alot of weight. To incorporated the two leaf design in the ceiling, if i took my original idea of fixing some material across the beams (something closed weave and dense, take carpet as an example) and stuck some insulation on the top of it, would it act as a second leaf?? i think thats all for the mo, i'm sure i'll think of something else :D

here are some pic's showing what i have to work with for question number 2.

I have been pondering about my wall design and something that was said by Stuart (soundman 2010) on a topic about a practice room here in the uk. if you have a look at the attached, you will see both my current and new wall design's based on 2 leaf's. The old design is of inside out design, incorporating comments made on this thread. The new design has more mass in it, between the leaves but does not have an air gap. In Johns Recording html file it states that this is ok as long as the insulation in the gap between the frame and the brick wall is open cell type. question: 1) is the new design a better option as it has more mass? (the internal frame of the box is self supporting and therefore does not touch the wall or ceiling at any point). 2) if no. 1 is yes, then is say your typical rockwool insulation (rwa45 or simular) of open cell format or is this something different? Any help to clarify will be appreciated :D

The new design has more mass in it, between the leaves but does not have an air gap.

Ummm.... Yes it DOES have an air gap! You show the air gap on your diagram as being 75 mm and filled with insulation. That is the air gap, and that is fine. In fact, your air gap in this design is much bigger than it was in the previous design. In physics terms, you are building an MSM wall, meaning "Mass-Spring-Mass". The spring is actually damped, to reduce resonance. Your "damped spring" consists of the air and the insulation. Together they form a damped spring. They act together. Take out the insulation (which is what you had in your original design: no insulation) and you lose your damping, which greatly reduces isolation.

In Johns Recording html file it states that this is ok as long as the insulation in the gap between the frame and the brick wall is open cell type.

Yep. Mineral wool and fluffy pink fiberglass are great for this.

The new design has more mass in it, between the leaves but does not have an air gap.

No it does not have more mass in it. The mass of the insulation is practically negligible, for the purposes of calculating your MSM resonance and your isolation. Drywall is many, many times more dense than insulation. The purpose of the insulation is NOT to add mass, but to damp resonance in the air gap.

question: 1) is the new design a better option as it has more mass?

It is better because it has a much large air gap! You have not changed the mass at all, since you show the inner leaf in both cases as being exactly the same: a single sheet of 12.5mm drywall. the new design is better for one reason only: It has a much bigger air gap. However, it still won't give you good isolation, since you still don't have enough mass on the inner leaf. 12.5 mm drywall is too thin to be useful. It suffers from many drawbacks: lack of mass, too flexible, high resonant frequency, etc. I'd suggest that you replace it with 16mm drywall, and if you need really good isolation, then make it two layers of 16mm drywall. And if you need incredibly good isolation for low frequencies, then put Green Glue in between those two layers. So, to summarize, your original design was really bad for three reasons: very small air gap, no insulation, and low mass on the inner leaf. With your new design you have fixed two of those problems by increasing your air gap and adding insulation. Now all you need to do is to fix the mass issue. - Stuart -

Thanks Stuart, really appreciate you taking the time to clarify things for me. I think im understanding things a lot better now :yahoo: