Soundproof Your Studio Wilson Harwood

FREE Soundproofing Workshop: https://www.soundproofyourstudio.com/workshop

I typically design home recording studios, but a home theater uses the exact same principles for isolation. In this article I will go over my favorite, floor, wall, ceiling and door designs for a home theater. 

 

1) Pick The Room Size
Now a home theater is not a recording studio, but room acoustics are still very important. You want to hear the dialogue in your favorite movie and you want the bass to hit crips and hard without a lot of mud. 

The best way to ensure you have a great starting place for room acoustics is to get some favorable room dimensions right off the bat. To do this I recommend starting with the Sepmeyer Ratios, but also using a tool called AMROC that is free to use online. 

I have a great video that goes in depth on room ratios and how to use the tools here: https://youtu.be/mpZsn9FcZnQ

The main thing is to not get overwhelmed by room ratios, but see if you can use them to your advantage when designing the floor plan and ceiling height of your proposed theater. 

 

2) Build On A Concrete Slab
When you build in a basement or garage or new addition with a concrete slab you don't have to do anything to soundproof the floor. This is a huge cost saver. Concrete is super heavy and concrete in the earth gives you plenty of isolation for a home theater. For this reason I would never build a home theater on a wood deck on the first or second floor of a house. It just isn't the right place for a soundproof home theater. 

 

3) Use A Double Wall System 
Next your walls should be two 2x4 walls with a 1" air gap between them. The walls should each have some owens corning pink insulation in them and should have 2-4 layers of 5/8" type X drywall on them. If the outside wall is your concrete basement wall then simply build a new wall at least 1" from the existing concrete wall. Below is a diagram of a typical double wall system. 

 

 

4) Use A Decoupled Ceiling 
The best option for your ceiling is to decouple the drywall from your existing ceiling joists. If you have the room to lose some ceiling height you could frame a new ceiling off your inside wall of the double wall system, but this is usually not the case in most homes where ceiling height is limited. For this reason, I recommend using acoustic clips like the I-B1 Clips, Whisper Clips, or Hush Frame Rafts attached to the ceiling joists and then attaching furring channel to those clips. You then will hang 2-4 layers of 5/8" drywall from those clips. 

***NOTE*** How much drywall should you use? For a home theater I would recommend 3-4 layers of drywall because of the low sub woofer bass. Low frequencies require more mass so use as much drywall as you can afford. 

 

5) Soundproof Door Design 
Ideally, your home theater would have only one door since soundproof doors are expensive. I recommend using a communicating door system where you have one door on each side of your double wall system. The key with your doors is that they are heavy and air tight. I have a great video that goes in depth into my soundproof door design here: https://youtu.be/2Rm1DC5HTfg

I recommend using solid core doors and then adding mass to them using 3/4" plywood. Then I recommend buying acoustic seals that will surround all four sides of each of your soundproof doors. This way your doors will be as soundproof as your walls and you will not have a weak point in your home theater where sound can come in or out. 

 

Conclusion:
I hope this article gave you a starting point from which to dive deeper into what it takes to properly soundproof a home theater. If you are serious about designing your theater right the first time than sign up for my soundproofing workshop below or jump on a soundproof clarity call with me on my home page. 

 

FREE Soundproofing Workshop: https://www.soundproofyourstudio.com/workshop

I get asked this question a lot: where should I put my vapor barrier in my soundproof wall? In this article I will teach you some best practices for installing vapor barriers and how they relate to your soundproof system. 

 
1) When you need a vapor barrier
Vapor barriers are a common aspect of normal construction and are still needed in soundproof buildings with walls and roofs touching the outside environment. You do not need a vapor barrier with interior walls, you only need a vapor barrier around the entire envelope of your structure. 

Let's take my studio for example, I have four walls touching the outside and a roof. My vapor barrier should be a continuous material that covers all the walls and ceiling and ideally never breaks a seal even where the walls and roof rafters meet. 

 

2) What is a vapor barrier used for and why you need one?
The vapor barrier is meant to control condensation build up in your walls and roof and floor. It is needed because the build up of warm moisture inside your building in the winter will want to move to the outside cold air and will condensate on the cooler exterior surfaces of your building like the exterior sheathing leading to moisture damage. In reverse, in the summertime, the warm moist air from the outside will want to enter your cool air conditioned building leading to condensation on the outside surfaces and inside surfaces due to tiny air leaks in your building envelope. 

You notice I say the moist air "wants to move." If you remember back to high school physics high energy states like to move to low energy states to create equilibrium. Hot moist air is high energy and cold dry air is low energy. The two will want to reach a state of equilibrium leading to moisture traveling to cooler surfaces and condensating which leads to mold and mildew growth. 

 

 

3) The problem with polyethylene or "poly" vapor barriers
According to Pretty Good House: A Guide to Creating Better Homes, polyethylene or poly, as it is commonly known, is not an ideal vapor barrier in all but the coldest climates. The reason is that the membrane was usually rendered useless after many staples, nail holes and other tears were introduced during installation (Kolbert et al., 117). 

What is the solution then? The answer depends on your type of construction and this is where things get interesting. If you have a double wall construction then the vapor variable membrane is ideal. if you are using single wall construction with acoustic clips and channels then you may want to use a different approach. I will go over all the options in the following section. 

 

4) Vapor Variable Membranes
A great solution for your soundproof building is to use vapro variable membranes. "Vapor-variable membranes are designed to resist the passage of water vapor from the interior into wall and roof cavities in winter but allow any accumulated moisture to dry to the interior when the seasons change" (Kolbert et al., 118). You can buy vapor-variable membranes from brands like Pro Clima, CertainTeed, Siga, Delta and Rothoblaas. In climates with both cold and warm seasons the membranes should be installed between the drywall and the studs of the inner wall. 

Compared to poly these membranes are more durable and will not rip or tear as easily. They still need tapes and seals at their seems and should always be installed according to the manufacturer's guidelines. 

 

 

5) Spray Foam 
Closed cell spray foam can work as a vapor control layer, however only if it is installed correctly. If any gaps or shrinkage occurs in the spray foam then water vapor can still get in and condense inside your walls. Make sure if you use spray foam that you create a continuous layer even over the studs themselves. This could mean increasing the gap in your double wall system because you don't want the spray foam to attach to your inner wall. The closed cel

FREE Soundproofing Workshop: https://www.soundproofyourstudio.com/workshop

Do you need to float your soundproof walls or can they sit on the existing floor? In this article we will go over when you need to float your walls and when you don't. I will also cover some basic techniques on how to float a wall. 

 
1) When do you need to float your walls? 
Most of the time I try not to float walls in my designs. The reason is that it adds more cost and time to the build. However, there are times when you should float your walls. When you build on any floor that is not heavy concrete you must float the floor and probably should float your walls as well. This is especially true if you are building on the second story of a house and your walls would be connected directly to the rest of the home if you did not float them. 

One of the major aspects of sound isolation is reducing or eliminating flanking paths. This is where sound travels from one material to another and eventually into your room When wood walls touch a wood floor the sound easily travels from the floor to the wall and into your studio. 

So how do you fix this problem? 

 
2) How To Float A Soundproof Wall (Overview)
There are two main options when floating walls. One is to use special acoustic isolators under the wall that decouple the wall from the floor and the other is to use common materials like neoprene rubber, or mineral wool to float the wall. 

Rod Gervais, in his book "Home Recording Studio, Build it like the Pros recommends using ND Isolators from Mason Industries. (Gervais, 276)

 

example of Mason Industries ND Isolator

To buy the correct isolator you need to know the load of your floating wall. First, you need to calculate the weight of all the lumber, drywall, doors and windows in your wall and then you can purchase the correct isolator for the wall. This is not a fun task, but can be done by diagraming out your wall design on paper or in a CAD program and adding up the weight of each material. 

If you are using mineral wool, rubber or an isolation pad you still need to know the how much weight the spring can handle. If the mineral wool for example is not dense enough then the wall may compress the mineral wool too much leading to less isolation. If the mineral wool is too dense the wall may not compress the wool enough leading to more sound transfer. Ideally, the mineral wool would compress about 50% creating an equilibrium where the force exerted down is equal to the elastic force of the wool leading to the best isolation possible. 

You might be wondering, how do I figure all this out. The answer is either through the manufacturer's manual, such is the case with the ND Isolators or by using techniques that have proven functional. In the second case you would have to find charts showing the percent compression of the product with different weights added on top of it. As you can see all of this is fairly complicated, but it is an option. My point here is to not teach how to float a wall in depth, but more so, show you what is technically possible. 

 

3) When You Don't Need To Float A Wall
When you are building on a concrete slab in a garage, basement or new building you do not need to float your walls or your floor. Concrete on earth is a great isolator and for most home studios, home theaters or offices will work perfectly as your isolation system for the floor. The only reason you may still want to float a wall on concrete is if lots of sound is traveling through the concrete floor. 

Say for example, your studio is built on a concrete slab shared with a car mechanic shop. The shop would be driving cars on the slab, dropping tools, running heavy machinery on the slab and all those vibrations could travel through the slab into your studio. In this case, I would say don't build a studio there, but if you had to you would want to float your walls and floor off the slab. 

 

Conclusion
Now you know when you should and should not f

FREE Soundproofing Workshop: https://www.soundproofyourstudio.com/workshop

Books I Recommend - (Affiliate Links)

Home Recording Studio: Build It Like The Pros by Rod Gervais: https://amzn.to/48ONVF6

Home Recording Studio Design by Philip Newell - https://amzn.to/4b7zyxd

Master Handbook Of Acoustics by F. Alton Everest and Ken Pohlmann: https://amzn.to/3Olwio7

 

If you are fortunate enough to buy a home with the intent of building a home recording studio then you should look for specific characteristics in the home. This article goes over what to look for when you plan to a build a recording studio in your new house. 

 
1) Build From The Ground Up or In an Existing Structure
The first question you need to decide is if you want to build in the existing house or barn or shed or from the ground up in the back yard. Both have pros and cons. Let's take a look at what to consider here: 

A New Build
Pros:


You don't have to deal with limitations in your existing house
You can get ideal room ratios 
You can get an ideal layout 
Electrical and HVAC can be optimized for the space
You can have higher ceilings and more room volume
Everything can be customized

Cons: 


It costs more to build from the ground up
It takes longer to build 
It will eat up your backyard space 
You will most likely need to permit it and go through codes
You need to pour a concrete slab and trench electrical 
The design possibilities are endless since you have a blank canvas

 

In An Existing Structure
Pros: 


The build is cheaper
It doesn't usually take as long
Your limitations lead to easier design decisions because you don't have a blank canvas
You are close to other amenities in your house like bathrooms and the kitchen
You may not have to pull permits
You might have an easier time DIY'ing a project in your existing structure

 

Cons:


You should build on a concrete slab so basements and garages are ideal, which limits options
If you build in a garage you lose garage space
You will run into numerous constraints like space, structural beams or walls,  electrical, existing HVAC, ceiling height, floor mass, 
It is harder to isolate because you must decouple the studio from the rest of the structure. 
You may have multiple doors and windows which add thousands to the cost. 
The space may simply be too small

Hopefully this list gets you thinking of potential benefits and obstacles of each location. It might be wise to try writing down your own pros and cons list as a mental excercise in potential issues you could face down the road. 

 

2) What To Look For In A New Build
If you decide to build from scratch there are few things I would look for before purchasing a property. 


Can you build in your backyard and follow local codes? 
Can you build a bathroom in a detached dwelling? Nashville doesn't allow this. 
Will the grading in your backyard support a concrete slab with adequate drainage?
Can you trench electrical from your main house to the new studio? 
Do you have room to pour a slab - can a cement truck get in?

These are some things I ran up against when I built my studio. In some cases it might be better to add your studio on as an addition rather than detached dwelling unit or DADU for short. I would work with a realtor and contact your local codes department during the housing search to get a good feel for what is possible with detached units. 

***As a side note: I am note a fan of pre-fab sheds. They are cheaply made and tend to lead to more problems than solutions with studios. Stay away from any pre-fab buildings if you intend to soundproof it.***

 

3) What To Look For In A House or Existing Structure
The more common option for most people is to build a home recording studio in an existing space in their house or in a barn or shed in the backyard. This is a great option, but there are some serious pitfalls you want to avoid. First, I highly recommend only building a soundproof studio on a concrete sla

FREE Soundproofing Workshop: https://www.soundproofyourstudio.com/workshop

Many people have asked me how do you finish the gap between two doors or two windows in a double wall system without connecting the two walls. In this article I will explain how I finish the gap so to speak without physically connecting the two walls. 

 

1) A Quick Review of the Double Wall System
Many of you may be familiar with the hallmark soundproof wall system: two stud walls with a 1" air gap (30mm) with insulation in each wall and two layers of 5/8" drywall on the outside of each wall. This is the best wall system you can achieve short of two masonry walls with an 8" air gap between them. 

 
2) Communicating Doors 
With two soundproof doors you want each door frame to only connect to one wall. So, in our double wall system we would build one door and door frame for the outside wall and one for the inside wall. This leaves a gap between the two walls. So there inlies the problem, what do we do with the gap? 

First, before even building the frame I put 1/16" thick layer of rubber from the edge of one stud wall to the edge of the other stud wall. See the diagram below for a visual idea of this. 

 

You can buy the rubber on amazon or find a local retailer. Rubber is a natural sound barrier and does not conduct vibration easily. It has the added benefit of closing the air gap, which will stop odors that could develop in the wall from entering your studio. 

Once you have the rubber installed you can then build your door frames and hang your two doors with seals. Below is an image of the finished frames with the rubber gap visible. 

 

So now what do we do with the rubber since it doesn't look nice? Well, the next step is to fill the gap between the frames on all three sides with insulation and acoustic fabric. I recommend a mineral wool with 1.6-3 PCF density. This will function in two ways. First it will fill the gap and make it flush with the frame and the fabric will create a nice clean finished look. Second, it will help with isolation because the insulation will absorb the sound and dampen resonances in the door cavity. This works just like the insulation in our double wall system. 

Below is a diagram of the finished door frame with the insulation and fabric installed. To install the insulation you can simply cut it to size and stick it in the gap. Then use construction staples to attach the fabric to each door frame and cover the staples and fabric with a nice finishing piece of trim. Any way works so get creative with the build, but don't attach your two walls with wood. 

 

 

3) Soundproof Windows 
The plan with the windows is the same except instead of door frames and door leafs you are dealing with window frames and glass. 

First, add your rubber all the way around the window rough opening on all four sides. See the diagram below for details. 

 

Next, once you have the window frames in place you can add the insulation and acoustic fabric to fill the gap between the two window frames. Again, below is a diagram showing this in one of my clients plans. 

 

 

Conclusion
So as you can see, it's not really hard to ensure your windows and doors are decoupled, but it does take a precise system to do it. As long as you follow this method you will guarantee your windows and doors maintain their optimum isolation. 

FREE Soundproofing Workshop: https://www.soundproofyourstudio.com/workshop

In this article I will go over proper ways to wire your home recording studio to avoid ground loops, which can cause noise in your audio signal. I highly recommend you start with another one of my videos before reading this article as they build upon one another: https://youtu.be/itY4bpd_5JQ?si=emj9uZMWqppCN14Q

 
1) Proper Home Recording Studio Grounding
Grounding is the use of a specific wire that will send excess current directly into the ground of the earth. This is a safety precaution and every electrical system to code should have a grounding system. 

In home recording studios we want each individual ground to connect to the main ground in the building structure without sharing common grounds with each other. What does this mean? 

Imagine you have an outlet where your amp is plugged into and the amp has a three prong plug with a ground. Now imagine in that same room you have a lamp with a three prong plug with a ground as well. Ideally, each of those grounds would not be connected and they would run seperate grounds to the main panel without sharing a common ground wire. Here are two diagrams showing the wrong way and the right way to ground your audio equipment. 

The Wrong Way -

 

The right way: 

 

Notice how in the right way diagram all the audio units go directly from the outlet to their dedicated spot on the electrical panel. These means ground are not shared with additional plugs in your electrical system.

Now, is this doable in all home recording studios, maybe not, but it is the best practice. With everything related to electrical I always recommend talking what you learn to your electrician and discussing options with them. The more you know the more you can teach them about how electrical power interacts with audio. 

 

2) Avoiding Ground Loops
A ground loop occurs when electricity mixes with the audio signal in a shared ground creating a circuit or loop which leads to hums and noise in the audio chain. Now, everyone has different methods for avoiding ground loops. Philip Newell states you should not have interconnected grounds at all, but the feasibility of this may be difficult in the home studio. Rod Gervais, another studio designer says there are two options. 

1) Remove one of the ground paths which would create a single point ground and close the loop. 

2) Or use an isolation transformer to "break the ground loop." Gervais talks about a unit called Tripp Lite that can be used to eliminate ground loops. (Gervais, 121) 

Gervais also recommends asking your electrician if you can install hospital grade isolated ground receptacles and a star grounding system. (Gervais, 122) The idea behind this wiring technique is to run isolated grounds from each electrical outlet that are then connected to the buildings own earth ground. The point is to know enough to ask your electrician if they are familiar with this system, but not to try and install it yourself. 

 
3) The Zero Loop Area Method
Neil A. Muncy coined the term "Zero Loop Area" as a way to stop ground loops from happening. His approach is to wire the studio in such a way that "loop areas" cannot happen. So now how do you do this. 

J.H. Brandt wrote a great paper summarizing Muncy's ideas. The best way to understand the zero loop area is to first understand the loop area. 

Imagine you have a tube mic that is plugged into a wall outlet because it needs power. That tube mic also must have an XLR cable (with a ground) that is connected to your audio interface or console. The electricity from both grounds form a loop from the console ground to the tube mic power supply ground connected by the electrical supply. Here is a diagram that will visually show this in more detail. 

 

So how do we fix the loop? The best way to prevent ground loops is to have all of your audio gear plugged into dedicated audio outlets behind your desk or if it is a live room at o