Garage studio build - couple of questions!

#1

Hello!

I was brought here by the reference article on MSM/MAM, which gave me some great insight!

I am converting my triple garage into a studio and live room for my drums, trying to isolate the sound as much as possible so that I don't annoy my neighbours.

The one thing that I'm a little stuck on is the best configuration for my walls. The garage walls are Besser blocks (masonry blocks), so I'm looking to create a room within it using a wood stud frame, insulation and dual drywall.

My original design was to go with: besser block -> 10cm decoupling cavity -> studs/insulation -> dual plasterboard.
You can see a rough sketch here: https://imgur.com/a/pk0Ka6o

Now after reading the reference article, I'm questioning whether the blocks themselves are a 2 leaf system, since the blocks are hollow inside?
If so, would that now create a 3 leaf system (which isn't as good as a 2 leaf)?
Should I be getting rid of the 10cm decoupling gap and just bring the studs flush to the block wall?

Any advice or tips on how I could configure this is greatly appreciated!

Thanks,
Dave

#2

if the block are hollow, you should try to fill them - sand, concrete, worst case foam. as far as the 10cm gap - the gap measures from the block wall surface to the plasterboard surface. so if your calculations on air gap were 10cm, then the depth of the frame should be 7.5cm leaving a 2.5cm gap from the block wall. this way you can (more easily) apply isolation sway bracing etc to stabilize the frame. in general, a gap between outer wall surface and frame only needs to be far enough to account for any surface irregularities (e.g. protruding cement, uneven stacking, etc) and avoiding contact. then you need to identify the proper distancing for the sway braces to attach.

#3

Thanks for your reply gullfo. Unfortunately I won't be able to fill the existing block walls, but cheers for the info on the gap distance.

#4

Here's an update!

I'm looking to start the studio build over the next two months, and I've consulted with a builder who will be putting it all together with my specifications. I thought I'd share more details of my project to see if there were any recommendations, advice or changes that I could make before I finalise the plan and commence.

As mentioned, this will turn my triple car single storey garage space into a recording and practice studio (mainly drums) by creating a room within the room using a 2 leaf system, while leaving a small amount of the garage space adjacent to wall (B) for general storage.

I've spent the past few months to dig deeper into learning more about acoustics, reading Rod Gervais' book, and going through forums like these. I'm still quite new to it all, but I hope that this plan helps to create a great sounding room.

I've tried to convert metric to imperial for easy reading, sorry if the figures aren't correct!

Goal
• The goal is to use the larger area for predominantly recording and some mixing, while having the smaller area for teaching drum lessons.
• So that I have the freedom to make noise at any reasonable time of the day without annoying my neighbours, I am trying to do the best I can to limit the amount of sound that goes out, while staying within a budget.
• I believe that the walls will be high performing, but can only do so much with the ceiling because of cost.

Room Info
• The dimensions of the attached floor plan below were taken from the garage in its current state which are all masonry concrete block walls, except for wall (B) which is just standard drywall connected to the house. I'm assuming that the block walls are only core-filled near the expansion joints and surrounding the garage panel doors.
• Ceiling height is 2.75m (9ft).
• Floor is standard concrete slab.
• The space is estimated to be 44m² (474ft²) / 120m³ (4237ft³) once the walls are built (I hope my math is correct haha).
• If it's worth anything, Cairns has a tropical climate. The average annual max temperature is 29°C (84.2°F), with 62% humidity. This does get hotter in our summer with humidity reaching 80%.

Design
• The 3D designs I have created are a rough guide on what the studio will look like when completed with acoustic treatment, though I will need to test the room modes once the walls are up.
• I've opted to have the listening area against wall (A), so that sound travels along the greatest length of the room.
I'm still unsure where the best spot for the main recording kit would be, but if anyone has any recommendations, I'd love to hear it. The student kit's aren't a priority, so I've backed them into the corners of wall (C) to create more overall space.
• I thought that having less 90 degree corners would be a good thing, so I've created wall (E) as a small closet for drum stuff.

Existing block wall
• Remove internal block wall and replace with a support beam.
• Remove both garage panel doors and their ceiling railing.
• Fill the empty garage panel door space with core-filled block walls.

New wall construction
• 90mm (3.54") steel stud frames built around the entire room that are decoupled 2cm (0.78") from the existing block walls.
430mm (17") is usually the standard OC stud width here in Aus, is there any benefit to using 580mm (22.8")?
• R2.7 insulation batts (Pink Soundbreak, Earthwool Soundshield or Bradford Soundscreen) fitted to all stud frames.
• Double 16mm (0.62") drywall (Gyprock Fyrechek or Boral Firestop) on all stud frames.
Green Glue is stupid expensive to get over here, and to be completely honest I'm not sold that it will do as much as it says. I've read a lot of both good and bad reviews and I can't justify the cost. I also couldn't find a local brand substitute to use between the sheets, so I think the best I can do is make sure that the drywall joints are staggered to minimise any board vibration. If anyone has any other advice, I'm all ears!
• Another stud frame added to wall (B) on the external side storage area. Staggered double wall configuration for this wall, fitted with R2.7 insulation batts and double 16mm drywall like the rest.
• Standard cornice, skirting and architraves around the room.

Ceiling construction
• 1x layer of 16mm drywall mounted to entirety of existing ceiling.
• R4.1 insulation batts fitted to the ceiling joists.

Doors
• All doors will be solid core, have no glass, and hung in separate frames if possible. I have been advised to get 43mm (2.5") thickness or above, but it will depend on cost.
• Double door on walls (B) and (D).
• Single door on wall (E).
• Lorient LAS7005si, batwing and drop seals applied to all doors.

Electrical
• 6x powerpoints spanned across the room.
• 1x 4-6kW air conditioning unit and 1x ceiling fan.
• 5x dimmable downlights.
Has anyone had any experience with dimmable lights causing buzzing or humming noise?
• Electrical boxes/outlets wrapped with putty pads.
• There is a manhole in the garage, so I'm thinking to use this opening to create an active ventilation system. The manhole will be cut to fit the grill, which will feed air from inside of the house through a flex duct pipe. The top-side of the manhole will have 16mm drywall and thick insulation batt to help reduce sound leakage.

Flooring
• Vinyl plank flooring fitted across the studio, with underlay if required.
• 40mm (1.6") thick EVA "jigsaw" martial arts mats underneath the recording kit.
• Standard carpet rug underneath the student kits.

Other
• All drywall, cornice, skirting, architraves and electrical gaps are to be filled with fire/acoustic caulking sealant.

Acoustic Treatment
All of the stuff in this section is just a guess, based on common treating practices for rooms this size. I have never used REW before, but I plan to let that guide me in the right direction. Do people generally test the room modes while the room is bare (new walls, no treatment) or once a bit of general treatment is in place?
• VocalBoothToGoacoustic VB73-G acoustic blankets. I already own these, and I've found them to be great for high frequencies with the bonus of being able to close/open them if I wish to dry out the sound a little more/less. They also serve as a way to separate the student area from the recording area if needed.
• Verbox (Australian company) 120cm x 60cm x 20cm (48" x 24" x 7.9") fabric wrapped polyester acoustic panels, placed on walls and ceiling in areas that are likely to have broadband frequency reflections. These are proposed to be multiband that can absorb down to 100Hz, with a 20kg/m3 mass. I'm looking to order 25-30 total for the walls and ceiling.
Moving on to traps and diffusers - I still get confused a little bit with these. I understand what they are both separately used for, but I get a bit lost with what type to go with (skyline, QRD, binary), how many are generally needed, exact positioning etc. They're also so expensive that I wouldn't want to get the wrong option if I misinterpreted my REW data. I'm looking to get one of the corner bass trap options below as a safe measure, since I commonly read that most rooms of this size have some sort of low freq issue in the corners.
• Corner trap option #1 (refer to 3D design): Polyester filled super-chunk that is wood framed 60cm (24") x 60cm (24") x 80cm (32") front face, and 120cm (47") high. I would probably have 2 stacked to a total of 240cm height in each of the 4 corners.
• Corner trap option #2: 120cm x 60cm x 20cm polyester panel (same as the wall/ceiling panels), but with a wood frame and perforated plywood face. This would be facing out of the corner at 45 degrees with the wall corner being an air gap. I would assume to stack 2 of these for a total of 240cm height in each corner.
• For further diffusion, I'm juggling with the idea of adding stacked stone cladding to all of wall (C) to create a complete diffuser wall for some scattering/livening effect, but also as a nice looking feature. I don't know if this would be overkill and cause too bright of a room sound?

Would love to hear your thoughts, and thanks in advance for any advice.

#5

looks good and you're planning seems well defined. wasn't sure on the manhole for venting - but the important thing is drumming is a physical sport, and two drummers will consume oxygen and generate more CO2 pretty rapidly, so make sure you have capacity for at least 6 complete changes per hours and prefer 8x per hour as likely a better choice.

Soundman2020 - Studio Design Forum