Multi-purpose Music/Home Theater/Recording Studio

#1

Hello all!

First of all I would like to wish everyone a great 2025 and that everything goes well in your part of the world, despite the bad things that happen, intentionally or not. A special thought for those in California affected by the fires. Very sad.

Stephan here, french canadian...not bad in English but often need help by Google Translate. I could have used the title « I've been planning this (garage) studio for 15 years » but I don't want to compete with GraGra... :lol:

...however like him : after « more than » a decade of dreaming and researching I am finally ready to build my dream home studio! :yahoo:

I've read a lot on Recording.org, John's forum and in this one. I really appreciate the work that you all do to share very technical knowledge and help others, and I hope you can find the time to help me with my project. I also read many books and documentation (Rod's book, Audio Expert-E. Winner, Recording Studio Design-Newell, Acoustics 101-Auralex, and others). As I read, I accumulated several pages of reading notes, classified by category (Isolation, Acoustic, Electric, HVAC, …).

Here's the outline of what follows:

1. Overview
2. Background
3. Goals and priorities
4. Existing construction
5. Neighborhood / Pre-Construction Sound Transmission Test Results
6. Budget and Schedule
7. Questions

1. Overview

The goal is to finish an existing 24x40 feet (exterior measurements) building (next to the house) that I build in 2012 to become a two room building: a gym (around 25% of the total space) and a music studio. The wall separating the two rooms is not built. Initially, I wanted a two rooms studio like the pro studios (recording and control room) but after an initial drawing and placed my many instruments, I find that the best solution might be one big room, also considering that I am the only user.

Here is the exterior plan I succeed to make with SketchUp in 2012 (in the end, I only put one window on the right wall (the first one) :

The studio room will operate as a rehearsal, composing, recording, mix, listening to music and home theater (HT) space for me and my wife, friends and maybe my own bands. It possibly could be a LEDE room, so a dead zone in the front (mix/listening area) and a live zone in the back (drums). I realize that my needs are many and that I will probably have to make concessions. The gym can also be used to record vocals, electric guitar, djembe, etc...and the bathroom could also serve has vocal booth!

I mainly play acoustic drums so I need a good isolation. The HT sub need it too, I think. I don't have (and don't want to invest in) professional studio gear that cost thousands of dollars (and more) but I have semi-pro equipment. I live in a quiet neighborhood and my neighbors are quite far away. So I don't think I need a total isolation.

2. Background

In my spare time I'm a drummer and a little bit of a pianist/keyboardist/composer. I like to practice/compose and record my own music and once in a while I'm working with other musicians on projects. In my previous house, I had a space in the basement for my keyboards, computer and drum kit but I can't call it a recording studio. In fact, my studio was an Ensoniq TS-10 workstation keyboard (24 tracks) and I was only recording the stereo output into my computer. Here is my setup at that time. My drum kit (not pictured) was in the other part of the family room, near the TV and stereo... :

I made several plans at this time to convert the basement or to extend the house to build a studio but finally (in 2011) we bought a new house with enough ground to build a studio in a separate building. Then I started to read books and Internet forums.

In 2012, when I went to get my building permit, I learned that the regulations were going to change and if I had not build in 2012 I would have been limited in the size of the building. So I started building without having a precise plan (Error #1). I did the best I could with the knowledge that I had been able to assimilate at that time. And also the pressure from parents and friends, telling me that I was not doing a professional studio and not being too much of a perfectionist...and I also believed the nice words of the hardware store salesman! Anyway, I ended up thinking that the materials used for the exterior wall weren't that important (Error #2) because I thought "I'll make another wall inside"! (The « A room in a room » technique) I could blame and flagel myself all day long (I did it a little, I confess) but it wouldn't help. I have to move forward. One thing is certain, I don't want to improvise any more for the future.

At the beginning of 2013, while I was inside the studio screwing in slats in the gym with my friend carpenter, I said: enough! I decided to stop building until I had a plan. Then I’ve had to put the studio on hold so that I could continue my studio studying and also focus on other projects around the new house, finish the basement, music bands, ect.

3. Goals & Priorities

4. Existing Construction

First I summarize :

The 2x6 walls rest on an 8-inch concrete foundation (which itself rests on a 4-foot-deep footing) and a radiant heating system was poured into the concrete floor. (I don't plan on putting any floor covering in order to reduce costs...and scratches, and block the heat, and concrete is a good reflective surface.) I installed a 100A electrical panel connected to the 200A panel in the house. I also ran an accessory pipe (Internet, Security System, etc.) and a water pipe. I didn't put any window in the studio area in order to simplify soundproofing. The front part (gym) has 3 windows and a garden door, and I plan to use one or two sliding patio doors (Thermal doubling glazing) to let in some natural light in the studio. The structure is very stable and well insulated. Nothing has moved, nothing has cracked since 2012.

The following things were given to contractors: excavation, concrete, fabrication of trusses, front brick wall, heating system (except pex installation), electricity job, gutters. Everything else was done by me with the help of a more experienced carpenter, family and friends. I'm not very experienced at construction but I am able to use a hammer, a drill or a saw! A final word: there is no question of undoing what has been done, that is to say removing construction materials already installed, unless I absolutely have to in order to achieve my soundproofing goal.

Here are now some photos and explanations. I condensed it as best I could. Sorry if it's long. My goal is to explain well what I did because I know that the experts have to see how things are built to be able to give good answers.

BEGINNERS (like me): DON'T THINK THIS IS THE PERFECT WAY TO BUILD A RECORDING STUDIO. This is why I created this thread in the Design forum instead of the Construction one.

Photo 4-1. Foundation et footing. My contractor suggested that I do the back wall foundation higher to avoid water infiltration in the spring (because the land is sloping). In the photo there is no house in the back...but a seniors' home with 24 apartments (2 floors) was built 1 or 2 years later...

Error #3 : If I had a specific plan, I would have had to build a foundation to better support the wall separating the gym from the studio.

Photo 4-2. While compacting the sand, the contractor installed 2-inch thick, 2' deep Styrofoam insulation along the foundation (Dow SM Insulation Panel, R7.5).

Photo 4-3. Exterior part of the walls (before cladding).
Excel II Panel (wood fiber Insulation Panel ½'', mass 16 lb/ft3, R-1.5, includes an air barrier coating)
I put a Mulco Acoustik sealant (CAN/CGSB-19.21-M87 standard) at each joint.
Error #4 : Excel Panel = Not enough mass
Error #5 : Not sure if sealant was needed at this location...

Photo 4-4. Above the sand: Dow Insulation Panel + metal mesh + pex for the radiant floor (2 lines in the gym and 3 lines in the studio).
Error #6 : Since I have a heated floor, I think I should have put a vapor barrier over the sand, before the insulation.
Error #7 : Having installed the pex without thinking about the interior wall (which should normally be nailed or screwed into the floor)

Photo 4-5. The two 40' walls were built in four 20' sections.

Photo 4-6. Who can boast of having ever walked in a field with a 20' 2x6 wall? :lol:

Photo 4-7. End of the walk.

Photo 4-8. Pouring the concrete floor 5 to 6'' thick (4350 psi) taking care to lift the metal mesh so that the pex is approximately in the middle of the floor (done by the best contractor in town). After that : Polish the floor, wet the floor for a few days (so that the concrete does not harden too quickly) and application of two coats of sealant (Diamond Clear Vox).

Photo 4-9. Installation of trusses. Hipped roof (4-sided roof, like the house and the garage).

Photo 4-10. Aspenite (OSB) 5/8'' tongue and groove for roofing, asphalt shingles and a ventilation maximum.

Photo 4-11. Wood slat and James Hardie fiber ciment siding on three walls.

Photo 4-12. Brick for the front wall. Soffit and exterior lightning installed.
(I didn't put brick on all 4 walls to reduce costs. Just the front wall cost $3k.)

Photo 4-13. Ceiling Fiberglass Thermal Insulation R-35 (RSI 6.10) Owens Corning then Enermax panel (wood fiber ½'' cover by vapor barrier, mass 14.5 lb/ft3, R-3.0). Since (at this time) I was thinking of making an interior wall (and ceiling), and winter was approaching I thought I could insulate and close the walls and ceiling to be able to heat during the winter and store things.
Error #8 : Enermax Panel = Not enough mass (the beams of the trusses can support much more)
Error #9 : The vapor barrier. I cannot add a second one on the interior (new) wall. « Vapor barriers always go on the surface that will be warmest in winter, so you would not put it up against the outer wall” (Stuart) And I cannot remove it without removing the entire panels.

Photo 4-14. Fiberglass Insulation R-19 in walls (density of 12.1 kg/m³).

Photo 4-15. Enermax Panel on walls too.
Error #10 : Enermax Panel = Not enough mass (the foundation can support much more)

Photo 4-16. At the bottom of the walls, there was 2'' of uninsulated foundation concrete. So before putting the Enermax at the bottom, we insulated the foundation (and a part of the insulation panel) with urethane. Then we put the Enermax on top of the urethane. I'm not sure this was the best way to deal with it.

To be continued...

#2

Photo 4-17. The result.

To better understand:

: Exterior wall 1.JPG (32.63 KiB) Viewed 127 times

: Exterior wall 1.JPG (32.63 KiB) Viewed 127 times

Had I known what I know now, I might have built the wall this way, because the foundation can support a great deal of weight. Maybe that would have been enough for my soundproofing needs

(air barrier and vapor barrier not shown):

: Exterior wall 2b.JPG (26.97 KiB) Viewed 127 times

: Exterior wall 2b.JPG (26.97 KiB) Viewed 127 times

On the other hand, someone in the construction field told me that putting OSB on an exterior wall (here in Quebec) could cause humidity problems...???...anyway. What is done is done.

5. Neighborhood / Pre-Construction Sound Transmission Test Results

I live at the end of the neighborhood. The neighborhood is generally quiet, with the occasional sound of a motor vehicle in the roundabout (motorcycle, all-terrain vehicle or snowmobile).

There is a fairly large distance (in my opinion) between the studio and the neighbors, as you can see on the Google map image below. The studio (the red S) is 60 feet from the house, 75 feet from the street (so my neighbors across the street are over 150 feet away), 70 feet from my back neighbor's driveway, 100 feet from my next door neighbor, and 60 feet from the senior's house (in theory, the older you are, the less you hear...lol). So, yes I need soundproofing but I also don't want to do too much for nothing.

After the building, I set up a drum kit and an MP3 player with speakers (towards the back of the building) to test the building's soundproofing with a Radio Shack sound level meter.

Table 1 – Tests with a rock song and Drum kit.

Table 2 – Tests with a rock song and a few low frequencies.

My conclusion : the wall seems to have a TL around 30db for low freq.

NOTE (1): As the building currently stands, I suspect that sound is coming out of the windows a bit more than the walls and roof. Since there will be no windows in the studio, the walls/ceiling may have a better level of soundproofing than my tests show.

NOTE (2) : Low frequencies make some fiber cement boards vibrate. Not good.

According to the municipal bylaw that I found on my city's website: "the noise measured one meter (1 m) from the boundary of the property where the disturbing device is located on the neighbor's side must not exceed 50 dB(A)". But in practice, no neighbor will come and sit down to have a beer or sunbathe right in front of the studio wall. And especially not in winter!

Moreover, I read that the “perfect decay” (transmission loss) is -6 db each time the distance is doubled. Although my tests do not perfectly reflect this rule (perhaps they are not reliable enough), if I use a conservative value (-4 db) and an SPL of 80 db at 3 feet from the wall (outside), here are my calculations:

So, in theory, since my nearest neighbors are 60 and 70 feet away, they shouldn't hear almost anything!? BUT, I suspect that these calculations do not take enough account of low frequencies. The ones that interest me the most are:

Bass guitar: 40-400 Hz
Kick drum: 50-500 Hz
Snare: 100-300 Hz
Toms : 80-500 Hz

So, if I am very conservative and drop the decay to only 1 db, here is the new calculations:

Very Conservative Decay
3' = 80 db
6' = 79 db (-1)
12' = 78 db (-1)
24' = 77 db (-1)
48' = 76 db (-1)
96' = 75 db (-1)

So I guess I should cut another 15 db (45 db total) to have 65 db outside and then 60db at my neighbors. It should be ok for me if I hear a little “boom boom” at 1 meter of the wall (outside).

6. Budget (CAN $) and Schedule

Gym: I estimate the gym to be finished at around $13k, including the air handling system (ERV, conduits, etc...) costing $7k (which will also be used for the studio). I am dealing with a qualified contractor and the plan he made and the equipment he chose for my needs will be OK. More on that later. No special soundproofing for the gym, except for the wall that separates it from the studio. However, I am planning to put acoustic ceiling tiles and maybe some acoustic treatments here and there. The room will measure approximately 11x22.

Studio: I would like to not exceed $27k, which includes: materials, sealant, electrical (circuit breakers, wires, light fixtures, outlets, switch, ...), plumbing, audio wiring, snakes (2), materials to make acoustic panels, projector and giant screen ($2k). I already bought two used patio doors in 2012 for $160. I am not sure if I will need an air conditioner but I intend to do what is necessary in anticipation (circuit breaker, electrical cable, hole in the wall to the outside, sealant, ect.). The room will measure approximately 26x22.

Total estimated budget: $40k

I'm going to do as much of it as possible myself with friends and/or hiring help here and there. My goal is to be done in September or October 2025, before next winter. I can work almost full time on this project. This is the first and last studio I will build.

7. Questions

I stop here (this post is quite long) to give you time to answer questions and make any comment/question you deem relevant. I will then continue with my preliminary plan, soundproofing ideas and further details.

Stef

#3

1. yes but maybe overthinking it a bit - your levels are already pretty good at the property line and once you get the resonances in the walls stopped and maybe window shutters (i'd think you'd want the daylight option), you should be good.

2. yes

3. the enermax doesn't seem dense enough to consider it as a "leaf". if the wood slats are open (like an inside-out wall / ceiling) then it's only partially a "leaf".

4. leave it. it's not really worth the expense to redo it.

5. definitely keep in mind a hyperinsulated sealed space need continous air exchange to remove CO2, so investing in a proper HVAC system is critical - do not wait to plan it - do it today. too many studio building projects leave it until the end and then it's really a nightmare to correct it. note that split units do not provide fresh air - get a proper ducted solution, possible with multiple zones - one for the gym and one for the studio so you can set temperature and humidity levels. a good quality ERV for the air exchange.

#4

Thanks Glenn!

Your answers are very encouraging. If I understand your answers to questions 3 and 4 correctly, I could make an interior wall while leaving the vapor barrier where it is (Enermax) and without adding a second vapor barrier on the interior wall. I will come back to this subject soon.

Regarding HVAC, yes I know this critical part and I already signed with a contractor for an ERV with 6 inches steel ducts, with 1 push/1 pull in the gym and 3 push/1 pull in the studio. More on that soon.

Stef

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