Soundproof Your Studio

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There are many soundproofing underlayments on the market and one of those materials is Tecsound. Now Tecsound is sold in the UK and throughout Europe, so it doesn't apply to those of us in North America. That said this type of product is similar to MLV and other visco elastic polymers that add mass to a structure and dampen sounds. 

In this article I am going to go over what Tecsound is and when and if you should use it on your soundproofing project. 

Before we dive in on what Tecsound is I wanted to go over what damping is. According to Technicon Acoustics:

"Damping removes vibration energy from a structure or system by eliminating the dynamic stresses associated with vibration." - Technicon Acoustics

The way sound and vibrations are eliminated is because the product will flex and move converting acoustic vibrations to heat. 

Now damping is a useful tool when soundproofing, but it must be used with a soundproofing system to be effective. Simply hanging Tecsound on your wall would not make it soundproof. 

According to the Tecsound Data Sheet: 

"TECSOUND® is a high density polymer-based, asphalt-free, synthetic soundproofing membrane, that offers good acoustic insulation in different building elements.."

It is used in the following ways: 

· Soundproofing against airborne noise in ceilings and lightweight roofs.

· Reduction of impact noise level in all types of floors, sandwiched between floor slabs and loose-laid flooring.

· Damping of impact noise caused by atmospheric agents on metal decks.

· Combined with sound-absorbent materials, it offers products with high acoustic performance.

· Its applications in the industrial field cover from the soundproofing of booths to the acoustic insulation of machine-rooms, gutter pipes, sound damping of metal sheets, etc.

It essentially is a mat that can be put on walls, ceilings, roofs or metal to help reduce sound energy and sound vibration. 

Tecsound is not cheap. The cost per square meter for Tecsound100 (the best for soundproofing) runs at 14.87 Euros  per square meter and that doesn't include shipping and tax. I wouldn't recommend the lower Tecsound ratings of 70, 50 or 35 because the mass is so much less than drywall. I don't think you are getting as much value for your money. 

For most soundproof rooms and home recording studios I would not recommend using Tecsound. The reason is that the cost doesn't really outweigh the benefits. Let me explain. When we soundproof we need a system. Let's look at a wall for example. If we build a double wall system with two layers of 5/8" drywall on either side of it we will get an STC rating of 63, which is plenty good for a soundproof home recording studio. 

Adding soundproofing materials like Tecsound and Mass Loaded Vinyl can increase that STC rating, but it is not really necessary and I would rather add more mass than a damping layer. 

Here is my point, if you were to add one more layer of 5/8" drywall to your wall it would cost you 5.70 euros per square meter. That is a 38% cost savings over Tecsound, plus you get more mass on your wall, which means greater soundproofing. 

Tecsound 100 weighs 10kg/sqm while 5/8" drywall weighs 10.7lb/sqm. The drywall costs 38% less and weighs more. Yes, you do not get the damping, but mass is ultimately what we are looking for to increase the transmission loss of our soundproof wall. 

Now, there are certainly times when Tecsound will be your best option. It would be great as an inner layer of an exterior wall to the outside both as a vapor barrier and added mass and damping. It would be great if you cannot lose the 5/8" of drywall in your room. It also is useful for soundproof machinery, metal decks, and things like cars or boats where traditional soundproofing methods are not practical. I am proposing that Tecsound is not necessary and an added cost when soundproofing a room or home studio. 

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

I don't know about you, but life can be pretty stressful and chaotic. When I build and design soundproof home recording studios I try to make my job as easy as possible. This means eliminating as many decisions as possible and focusing on the overall goal of creating a quiet space that is enjoyable to work in. 

What I find is many people in our community and even clients of mine tend to overcomplicate the process. I think a lot of this stems from a fear that if they don't look at every option on the market in depth then their hard earned dollars will be wasted on a studio that does not live up to the high expectations they have in their mind. 

In this article I want to focus on what matters in studio design and what is mostly a waste of time. Let's dive in! 

There are so many soundproofing products that claim to help you eliminate noise. Some you might run into are: 

And the list goes on and on. No wonder most of us spend hours, months and even years thinking about how to design a soundproof home recording studio without ever really moving forward with building it. 

The truth is, you can build a great soundproof home recording studio without any of the materials I listed above. Here is how. 

You can float a floor, but it is not as effective or easy as simply starting with a concrete slab. Concrete is excellent at stopping sound, so I always recommend building your soundproof home recording studio on top of an existing slab or pouring a new one. 

If you want some rock solid soundproofing then use a double wall system. This involves two layers of 5/8" drywall on either side of your wall with a 1" airgap and regular cheap insulation in the wall cavity. Simple! Easy! 

If you are really short on space you can use a system of acoustic clips and hat channels to decouple your drywall from your wall, but it does make things a bit more complicated. 

When I design studio, I almost always use a decoupled hat channel system on my ceilings. This means using special acoustic clips and metal furring channel attached to your ceiling rafters. You then drill the two layers of 5/8" drywall to your hat channels and wallah, you are done. Easy! 

There are many ways to heat and cool a room, but my favorite design is to use a Mr. Cool mini split DIY kit. This allow you or your contractor to install the unit yourself, which saves thousands of dollars. I also love how quiet and efficient these units are. 

Yup, the mini split will not bring in fresh air into your air tight room. So, we need a seperate system to give you nice quality fresh air. I like using and ERV or HRV (depending on the climate) to bring in fresh air and pull out stale air from your studio. 

I run my ventilation lines through a baffle box which makes it so you can't hear the air noise or any noise transfer between your room and the outside. 

Don't sweat the details and don't get lost in tone of soundproofing supplies. In my designs, the only true soundproofing supplies you need are acoustic clips for your hat channels and acoustic clips to help as sway braces for your inner walls. If you need more soundproofing add more mass. That means use 3-4 layers of type x 5/8" drywall instead of two. Simple, easy and straightforward. Don't overcomplicate something that is by nature very complicated to begin with. 

FREE Acoustic Treatment Guide: https://www.soundproofyourstudio.com/acoustic

Do you have mixes that alway have too much or too little bass? Does your low end sound muddy on your speakers? Most rooms have low end problems and even acoustic panels cannot fix them. We need low frequency pressure traps to attenuate low frequencies. This article focuses on one such bass trap known as a corner slot resonator. It is fairly easy to build and give fairly broadband absorption down to the low bass frequencies in that 20-50hz range. 

The corners of the room are where most bass builds up and is therefore the best place to absorb all modal problems in your room. By putting a slot resonator in your corners you can target problem frequencies in your room. 

Now, notice how I said target frequencies. These acoustic bass traps are built custom to your room, so you need to know what frequencies are causing issues. To figure this out you need to measure your room using a measurement microphone and a software like REW. I go over this in other posts, so check that out before continuing. 

Once you have measured your room and found some offending low bass frequencies also known as room modes, then you are ready to attack them! Okay, just absorb them, but let's look at how to do that. 

A slot resonator is a form of Helmholtz resonator. These resonators use airspaces between wood slats and a depth behind that slat to attenuate bass. Here is the formula to figure out the depth of your corner trap, the width between your wood slats and the depth behind the wood slats. 

f = 2160* square root r/((d*D)*((r+w))

f = resonant frequency 

r = slot width

w = slat width

d = Effective depth of slot (1.2 times the actual slat thickness)

D = depth of box to the inside slat face

Now, the best thing to do is plug this equation into a spreadsheet to solve for the frequencies you want to attenuate. Another option is to use an online calculator like this one: https://www.acoustic.ua/forms/calculator5.en.html

For a diagonal trap in a corner your slot depth will very with each wood slat and you can vary the width between slats. 

The trap I have shown above has a center depth of 1' 7 1/4" with a 1/16" width between the 1x6" wood slats, which will attenuate at 46Hz. For my clients building home studios I like to build these traps custom so that each slot width and depth is targeting a specific problem frequency in their room. This will help get a smoother bass response at their mixing position. 

Designing these traps in 3D CAD program will allow you to accurately measure and design your traps to the 1/16." Accuracy is important with these traps since, a 1/16" difference can changer your resonant frequency by 20 or more Hz. 

Start by building a frame using 2x4 lumber for the bottom, sides and top plate. Then put in a 2" thick piece of Cornings 703 Insulation. Place fabric over the insulation and wood frame. This should be fabric you can breath through and feel air on your hand on the other side of the fabric. I recommend Guildford Of Maine's acoustic fabric. 

Last, you will attach the 1x6" wood slats to your frame on top of the fabric. The width between your wood slats and the depth behind the inside face of each slat will determine the resonant frequency your trap will absorb. Below is a diagram of how to build these traps. 

If you want to reduce low bass frequencies in your room and have a fairly broadband trap than these slot resonator corner traps are a great cost effective solution. Just take care to measure carefully and do the math to get the trap as accurate as possible so it absorbs the frequencies you want it too. 

FREE Acoustic Treatment Guide: https://www.soundproofyourstudio.com/acoustic

Low frequency issues are the biggest problem for soundproofing and acoustically treating a room. In this article I will discuss how to treat low frequency issues below 125Hz in your room using panel bass traps. 

Low frequencies below 125Hz are hard to treat with acoustic panels made from fiberglass batts. To treat these lower frequencies we need a different tool. The best tool for the job are pressure traps that use a closed air space to attenuate low frequencies. These traps are efficient at reducing low frequencies, but they have a narrow Q, meaning they only work in a narrow frequency band. For this reason I only recommend building these traps after you have extensively treated your room with velocity traps aka insulation with fabric over it. 

The bass trap I will be discussing has many names ranging from diaphragmatic absorber, low-bass panel trap, resonant absorber and so on, but the theory remains the same. These traps use an enclosed box with a calculated airspace depth to create a resonant chamber that attenuates bass at a specific frequency. 

To calculate our panel mass and depth we need to use the following formula to ensure our bass panel trap will attenuate the correct bass frequency. The formula is as follows: 

f (frequency) = 170 / square root of (mass x depth)

*For metric change 170 to 60 -

m = mass is in pounds per square foot  of resonate panel

d = depth in inches

Now the easiest way to calculate potential panel depth and materials is to create a spreadsheet for plywood thicknesses and depths and see what materials you need and depth you need to attenuate the correct frequency. 

Adding loose glass fiber to the back of your panel will increase absorption, but it also will move the peak absorption lower down the frequency spectrum. 

These panels are only effective when placed at a pressure maximum in your room for the desired frequency you are trying to treat. This means that you need to find out where a room mode is ringing out in your room and place the panels on that wall or ceiling. To do this you can use a calculator like, AMROC online to see where room modes in your room are, or you can play a sine wave through your speakers and walk around the room noting where the bass note sounds louder or completely gone. The places where the bass notes are louder is a pressure maximum and is where you should place a trap. 

Lastly, it is important to make each panel absorber at least 5 sq/ft to have an affect on the room. You will need to place one or two in your room to and re-measure your rooms response to see how many absorbers you will need. 

This is a good question. We know we have bass problems in our room, but now what? First, you need to measure your room. You must use REW or equivalent room software and a measurement mic that is properly calibrated to measure your room. This will show you what frequency problems you have in the low end. Let's use my studio as an example. 

Below is a picture of my REW results for the spectogram. I like to look at the spectogram because it shows which room modes are "ringing" out in my room at my listening position. 

Notice how most of my room is flat in the upper frequencies, but down low we get those flame like peaks. Those are my room modes ringing out where I mix. This will make my bass a bit muddy to hear since those frequencies don't decay at the same rate as ones nearby. 

The solution is to build traps that target those frequencies. It is analogous to a sniper rifle vs a shotgun approach. The panel trap can isolate those problem frequencies. 

So, the first ring out is at 106 Hz. Let's now look at where to place that panel. 

As I mentioned before, you can use AMROC or sine waves to find your pressure maxima at 106Hz in my example. For this example I will use AMROC to show you where that frequency modal issue is at a maximum. 

That 106Hz frequency is a tangential and oblique mode that is maximul at the blue and red areas on the Room 3D visualizer on AMROC. AMROC plays the tone when you hover over it so I also could hear a huge peak in the middle of my back wall. To treat this frequency I would build probably build a 2x4' trap and place it in the middle, bottom or top of my back wall. 

Let's now look at what mass and air depth I need to treat that 106 Hz frequency. 

Based on the math here we know that the thicker the plywood the thinner our box can be. I like saving floor space so I was going to use 19/32 OSB Sheathing. This is affordable and readily available at my hardware store.  

19/32 OSB weighs roughly 2 psf.  This means we have to do a little algebra to solve for the depth. 

106hz = 170/ square root (2 * d) 

square root (2*d) = 170/106

2*d = 1.6 squared

2*d = 2.56

d = 1.28"

The answer ends up being 1.28 or 1 9/32".

Yay! Okay so we have our box depth, now let's design the box.  

*it is a good idea to weigh your panel before building just to double check the math is correct. 

**You could use 2 lb MLV and absorption would be greater, since a limp mass membrane will add to absorption through damping. I might do this depending on cost and availability of 2 lb MLV. 

Okay we did our room analysis, we did some math, we got our panel material, now it is time to build this bad boy. Here is a mock up I did of how I would build a trap to have a center resonating frequency of 60hz. 

With a 106 Hz panel like in our example the box is so thin that I would forgo the insulation or use really thin insulation. With lower frequencies you can use the Corning 703 or a similar insulation to help improve absorption. 

Make sure to acoustically seal all corners with your MDF to make sure the box is truly airtight. When finished you can test the box using a sign wave at the resonant frequency you were hoping to absorb. Ideally you will feel the panel vibrate at that frequency. 

Bass trapping is much more labor intensive than velocity traps, but you can really tighten up your low end if you put them in the right spot and build them correctly. In the end you may want to buy a pre-made panel. Either way, remember to fully treat your room with normal acoustic panels before attacking your low end. 

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

There are several acoustic drywall brands on the market and one is SilentFX by Certain Teed. This is a Saint Gobain company who also make Green Glue. In this article I will go over the pros and cons of using SilentFX drywall in your soundproof studio build. 

According to Certain Teed, "SilentFX Noise-Reducing Gypsum Board is specifically designed to reduce airborne sound transmission between two adjoining spaces when used in wall or floor/ceiling assemblies." 

They go on to say that, "SilentFX features a viscoelastic polymer that dampens sound energy. Application of the viscoelastic polymer between two specially formulated dense gypsum cores results in a combination that significantly improves sound attenuation and is ideal for systems requiring high STC performance."

It is important to note that Green Glue and Mass Loaded Vinyl are both used to dampen sound energy as well. This middle layer viscoelastic polymer in SilentFX is meant to replace the need for Green Glue or Mass Loaded Vinyl. 

According to a paper from Taiyuan University of Science and Technology, "The viscoelastic damping layer, most of which is rubber or rubberlike polymers, represents hysteresis under a dynamic load. Part of the mechanical energy is absorbed and finally dissipated as heat due to the internal friction of the molecular chains." So, in plain english, these means that the material vibrates in such a way that acoustic energy is transformed to heat, thus eliminating some of the sound or noise coming through your wall. 

One of the best ways to soundproof a wall is to build a double wall system with an air gap in between the two walls. This system involves two layers of 5/8" drywall on either side of each wall. The STC rating you get from this design is 63. 

According to Certain Teed's technical data sheet their equivalent double wall system gets an STC rating of 62. Their wall uses one layer of 5/8" on one side and a layer of 5/8" SilentFX drywall with a layer of 5/8" type X drywall on the other side. The biggest difference between the two wall designs is one has two layer of 5/8" on each side while the Certain Teed wall uses three layers with one being their patented SilentFX drywall. 

SilentFX costs $73.01 per 4x8ft sheet. This is from Campbell Supply Company. (“5/8" Acoustic Drywall, Silent FX”) Type X 5/8" drywall costs $17.87 for a 4x8ft sheet. The cost of installing a the Certain Teed double wall would be a total of $126.62. The cost of a double wall without Silent FX would cost you $71.48. 

That is a difference of $55.14 and you are not getting a better STC rating. 

I wouldn't recommend SilentFX drywall for most home recording studios. It might be helpful if you are building a normal wall system and want some added acoustic benefit over regular drywall. However, the cost of acoustic drywalls like SilentFX never seems to justify the added acoustic benefits. For this reason I never recommend specialty drywalls to my clients. I always like to stick with regular Type X 5/8" drywall. You get the better results for less money. 

Works Cited:

“5/8" Acoustic Drywall, Silent FX.” Campbell Supply Company, campbellsupplycompany.com/5-8-acoustic-drywall-silent-fx/. Accessed 2 Oct. 2023.

Wang, J.; Sun, D.; Liu, S.; Zhang, X. Damping Characteristics of Viscoelastic Damping Structure under Coupled Condition. Math. Comput. Appl. 2017, 22, 27. https://doi.org/10.3390/mca22010027

Websites Referenced: 

https://www.certainteed.com/resources/CTG_2480_SilentFX_Brochure_Eng.pdf

https://www.homedepot.com/b/Building-Materials-Drywall-Drywall-Sheets/5-8-in/N-5yc1vZbb52Z1z0ppqa

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

Recently, a member of our community asked me to make a video about ICF or Insulated Concrete Forms. I had never heard of it and so I did some research. I was pleasantly surprised to see that ICF would be a great building material for soundproof home recording studios. Let me tell you why. 

ICF is a construction technique where concrete is poured into pre-fabricated blocks, kinda like lego blocks. These blocks are made out of styrofoam and are hollow to allow for concrete to be poured in. They are essentially a 6" to 12" concrete wall that is relatively easy to build and offers insulation as well as durability. 

So for soundproofing the styrofoam is not that important. What is important is the mass of the concrete itself. According to one ICF producer, LOGIX ICF, you can get blocks in foam to foam dimensions of 4"-12." All budget aside, the 12" blocks would be the best and the 4" blocks the least best. 

Below is an image from LOGIC ICF of their block system.  

According to Jenkins Design Build, ICF has a consistent STC rating of 54. That is really good for just one wall (Solutions and Technology). Now I would still recommend framing an inside wall with a 1" air gap, but you wouldn't need MLV or Green Glue and you would be fine with the standard two layers of 5/8" drywall. I would imagine drummers, loud bands and most home studio enthusiasts would be blown away by this type of design. 

Another benefit to ICF is that the blocks fit together seamlessly and are therefore air tight. This is another benefit to soundproofing and recording studio design. 

Lastly, let's look at another source just to understand how soundproof a concrete wall really is. According to the Master Handbook of Acoustics, two 6" concrete walls with 6" air gap will give you an STC rating of 59. That is without fiberglass insulation in the middle, which would increase isolation. 

A single 12" concrete wall would give you an STC rating of 51. The air gap and insulation is still a critical part of your soundproof wall system. (Everest, Frederick A., and Ken C. Pohlmann)

As a side note, concrete and brick massive, but do have the drawback of transmitting impulse noise easily. This means if you tapped on your concrete wall with a hammer, the sound would ring clearly on the other side. This is another reason the air gap and double wall system is desirable. 

Beyond soundproofing it is important to see other benefits to ICF. First you may save 2-4 months in construction time on a new build because the blocks fit together so easily. You may also save money on heating and cooling your structure. Jenkins Design Build estimates you may save 25-50% on heating and cooling costs. 

According to Marion Saxton with Ph.D. in Environmental Design and Planning, ICF can last up to 100 years, it does not need a vapor barrier, and it can save anywhere from 4.8%-14% in energy consumption over a 70 year lifespan. Both Saxton and Jenkins Design Build mention the benefits of ICF for homes prone to natural disasters like fire, hurricanes and flooding. (“Myth Busting: How Sustainable Is ICF Construction?”)

You may wonder why all homes are not built with ICF. There are some downsides. The first is the added upfront cost of building with ICF. According to Saxton, ICF cost around $150 per square foot. She also notes you will spend around 5-10% more in total construction costs than a wood framed house (“Myth Busting: How Sustainable Is ICF Construction?”).

According to Jenkins Design Build, ICF costs have just about caught up with wood frame construction. They say ICF blocks cost around $3.50 to $4.00 per square foot plus the added cost of concrete, rebar and labor costs. They say this still can add 15-20% more than stud framing, however, the total cost over time may be better with ICF (Solutions and Technology). 

Another downside to ICF is it is not DIY friendly. Whereas the average homeowner can learn to frame walls, it is not easy to learn how to install ICF. From my own research it would be wise to hire a contractor who has experience building with ICF to save you time and money in the long run. This means you might be limited by budget and availability in your area. 

Would I recommend using ICF? Yes, 100% if you can find a contractor and a quote that fits your budget. I feel ICF is a great choice for people looking for a way to build studios in their backyards. It doesn't work as well in basements and garages and for those people I would still recommend using a double stud wall system. 

The downsides don't seem to out weight the upsides in my experience and ICF seems especially appealing for studio designers. I look forward to hopefully designing and building a home studio with ICF in the near future and will let you know what I think. 

Works Cited

Everest, Frederick A., and Ken C. Pohlmann. “Sound Isolation: Walls, Floors and Ceilings.” Master Handbook of Acoustics, McGraw-Hill, New York, 2015.

“Myth Busting: How Sustainable Is ICF Construction?” Rise, 28 Aug. 2017, www.buildwithrise.com/stories/mythbusting-icf-sustainable.

Standard | Logix ICF (Insulated Concrete Forms). logixicf.com/products/standard/. Accessed 29 Sept. 2023.

Solutions, Bethany Jenkins under Home, and Technology. “Insulated Concrete Forms: Pros and Cons.” Jenkins Custom Homes, 8 May 2020, newhousebuilder.com/insulated-concrete-forms/.

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

When we start to design a soundproof home recording studio there is always a deep fear in the back of our minds. What if I spend all this money and then it is not soundproof enough? In this article I will talk about the 5 biggest soundproofing mistakes you can make and how to avoid them. 

It is so tempting to buy a pre-hung window from a window supplier when building your studio. It is cheaper and easier than building your own windows or buying expensive soundproof windows. However, this is a corner you don't want to cut! 

I have heard of many people buying casement windows, double glazed windows, tripple glazed windows and all sort of designs to try and save money thinking it will be good enough. The problem is that most windows use float glass and float glass is not a good sound insulator. 

For soundproof windows we want to use tempered glass and/or laminate glass and we need a large airgap of at least 4" and two differing, but thick pieces of glass. Below is a simplified diagram of the windows in my recording studio. 

In my studio I used a design by the studio designer, Rod Gervais. He recommends that you can build a single soundproof door rather than having two communicating doors. Having built the single door I do not agree with him. I now believe that all soundproof doors, especially to the outside must be double communicating doors. See the diagram below. 

By using two doors we can maintain the mass, air gap and decoupling needed to properly maintain the STC rating of our wall where the door is placed. 

There is so much talk on the internet arguing over should you use mass loaded vinyl, Green Glue or even carpet glue between you two layers of 5/8" drywall. I have taken the stance that MLV and Green Glue are nice to have and may increase the isolation of your wall, but they are not critical to the isolation of your wall. This is important to understand, because many people come to me and think they must use Green Glue. My response is always, well what is your budget. If they cannot afford Green Glue then I recommend not using it and simply doing two layers of 5/8" drywall on each side of their walls or even 3-4 layers if that is cheaper. 

MLV and Green Glue provide damping. Damping is a form of friction that turns sound into heat. This added physical phenomenon in your walls is a good thing, but as I said before a double wall without Green Glue or MLV will still give you an STC of 63, which is plenty good for a home recording studio. 

We all think we know a person who has a great deal on materials. Everyone has a brother-in-law who is really handy with construction and everyone underestimates how much their soundproof studio will cost. Before you begin building it is extremely wise to open a spreadsheet and input all the materials and labor costs for your studio to see if you can afford to build one. Most people look up a couple costs, try and estimate and don't really know how much their studio will cost in the end. Then half way through the project they are already over budget. At that point it is too late to find places to cut costs and they are stuck footing the bill for something they cannot afford. 

Don't be this person. Get accurate estimates and costs before you build and then add 20% on top of that estimate and that will be a healthy budget for your studio. Yes, it will be more than you expected, but it will be more accurate in the long run. Plus, wouldn't it be nice to finish under budget for once? 

The number one thing I see home studio enthusiasts do is forget to design and install a ventilation system in their studio. You can have the most soundproof studio in the world, but if it does provide fresh air and circulate out stale air then it is not going to be a good space to work in. 

Ventilation means fresh air exchange. It does not mean heating and cooling. Those are usually two seperate systems in a build. They can be combined, but they don't have to. Your air handler in your house will take the internal air and heat and cool it. It does not take outside air and condition it unless you have a system to do so. In a soundproof room the room is airtight. Unlike our houses where there are cracks and windows, and small openings where air can get in and out, our studio does not have those. We need a way to bring in fresh air and remove C02 laden stale air. 

To do this I recommend using and ERV or HRV. Both units will pull in fresh air from outside and pump into your studio, while removing stale air and pumping it back outside. The catch is we also need to silence the ducts and air flow in and out of our studio. To do that we add in a baffle box system so sound and the air flow do not create unwanted noise in our studio. 

I hope this article was helpful in addressing some of the major mistakes people make when trying to soundproof a room. Now that you are aware of them you can dive deeper into how to create solutions to avoid these soundproofing pitfalls. 

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

I have gotten so many questions about how to soundproof the outside exterior wall of a double wall system. This makes sense since all the double wall diagrams show two interior walls with sheetrock on both sides. This leads you to wonder, well how do I replace the sheet rock with an exterior wall material and still have it be soundproof? In this article I will answer exactly that question. 

First, let's take a brief look at how our walls are constructed to help us understand how we can modify this design. A typical interior double wall will have two layers of 5/8" drywall on a wood or metal framed stud wall. Then there will be at least a 1" air gap. After that there is another wood or metal frame wall. Insulation is installed in the wall cavity either filling both framing bays or having insulation in the bays of each wall. Either is fine. Lastly, the outer wall has 2 layers of 5/8" drywall. 

This is your typical double wall design and it would look something like the far right wall design in the diagram below:

 This gives you an STC of 63 and everything is great, but what about if that left or right side of that wall is an exterior wall. You can't just put drywall on the outside of a building, so what are you to do? 

So to solve this problem we just need to understand some soundproofing theory. The reason we use 5/8" drywall is twofold. First, it is relatively cheap and is a common building material. Second, it has mass. It weighs 2.2lb per square foot whereas 1/2" drywall is much lighter. 

Knowing that our inside wall will weigh 2.2lb per square foot per sheet of 5/8" drywall we can do some super simple math and know that our inside walls weights 4.4lb per square foot. 

Instead of focusing on the drywall, the key is to focus on the mass of the wall it self. Now we can build our exterior wall knowing it needs to be 4.4lb per square foot or more. 

In my studio, most of my walls are exterior outside walls, meaning they face the outside. This means my second wall has one layer of 9/16" sheathing and one layer of hardy plank siding. Let's calculate how much that weighs. 

9/16" Sheathing (nominal 5/8") = 66.37lb (4'x8' sheet) = 2.07lb per square foot

*(jonathan)

Hardy Plank Siding =  2.3lb per square foot

*(James Hardie® Siding FAQs - Homescapes of New England: 603.734.4282)

This means my total outside wall mass or weight = 4.37lb per square foot. 

This is just shy of my inside wall mass, but actually worked out perfectly. 

Now, I will be honest. I did not think about any of the math when I was building my studio. It was my first studio build and I really didn't know what I know now. So, to save you some trouble simply match your studio mass on both walls. Easy and you don't have to overthink it. 

Yup, I knew we had to go there next. So, if you use Green Glue on your inside wall you certainly could use it between your sheathing and outside exterior siding. This would guarantee you have equal walls. I did not do this in my studio and I don't really need it. 

You could also say that Green Glue is adding soundproofing to your inside wall and thus add more mass to your outside wall. How much mass, well that is up for debate. At one point Rod Gervais had said that GG is like having four layers of drywall. He has since pulled back that claim, but it is adding to transmission loss, especially at low frequencies. 

My advice, would be to not obsess over these minor details. Green Glue or no green glue, mass is still more important in my humble opinion. Focus on the mass and then add Green Glue if you want that extra boost. 

If you are building in an existing structure then your walls may not have much mass. A shed or garage may have thin low mass construction. In this case you can add mass as long as the structure can handle it. You can add drywall to the inside of the exterior wall or add more mass to the outside. How you do it is not as important as that you do it and the mass is correct. That magic 4.4lb per square foot is your mark. That is the number that matters on both walls. 

Works Cited: 

James Hardie® Siding FAQs - Homescapes of New England: 603.734.4282. 26 Mar. 2010, www.homescapesofne.com/services/information-about-james-hardie-siding/#:~:text=Hardieplank%20weighs%202.3%20lbs%20per. Accessed 12 Sept. 2023.

jonathan. “How Much Does OSB Weigh? (+ OSB Weight Calculator).” ToolCrowd, 17 Oct. 2021, www.toolcrowd.com/how-much-does-osb-weigh/#google_vignette. Accessed 12 Sept. 2023.

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

Some of you may know that I do Soundproof and Acoustics Consulting through my program The Soundproof Studio Blueprint. Recently, one of my clients Colin of Tone Lab Studios finished the program. We did a full podcast interview and video on his entire build. In this interview you will learn some of the key aspects of soundproofing an upstairs bedroom, the difficulties we faced and our solutions to those problems. 

Here is a list of minute markers in case you would like to jump around in the video:

0:00 - Intro 

1:30 - Podcast Interview Start

2:50 - Soundproofing Goals

4:07 - Soundproofing Results

7:54 - Floating Floor Design

9:44 - Wall Design

12:42 - Doors

18:46 - Ceiling

24:10 - Ventilation

31:31 - Acoustic Treatment

42:40 - Work With Tone Lab 

The goal with Colin's studio was to soundproof enough so that his roommate would not hear him mixing and recording. In the end he is very happy with the results and says that the only thing you can hear is the kick drum. This is very normal for a second story soundproof studio. Without having a concrete slab it is very hard to stop those 40 Hz frequencies from the kick. However, we knew going into the design that we were working within the constraints we had which included having to float a floor and a tight budget. 

Because we were building on a second story of his home we had to float the floor. Below is a diagram of the type of floating floor method we used with some modifications. 

This design uses a layer of 2" thick Corning 703 across the whole floor while leaving a 1" piece upturned around the edges. The key is to try and decouple your inside drywall and floor from the existing floor. To do this, I recommend using backer rod and acoustic caulk under your two layers of drywall and under the 1x6" baseboard. Remember this system is not perfect, but it was a solution given our budget and location of the studio. 

Colin did not want to lose too much space in his studio so we opted for using a hat channel system with acoustic clips. This made it so all of his walls were decoupled from the existing studs. We used two layers of 5/8" thick drywall on all the walls and ceiling. The hat channel and clips were also used to decouple our ceiling from the existing ceiling rafters.  

We did not use Green Glue to save cost, but if you have the budget I would put Green Glue on all the walls, ceiling and in between the two layers of plywood on the floor. 

Colin had 2 doorways. The first door way already had a place to frame in another wall in the bedroom making it a perfect rectangle. This allowed us to create a communicating door system with a sizable airspace in between. 

We used two solid core doors with Zero International seals all the way around each door. He also had a door directly in the middle of the back wall to a bathroom. We decided to use only one solid core door with the same seals on this door because the bathroom did not need as much soundproofing from his roommates. 

Every soundproof room needs a ventilation system. For Colin's studio we used a Fantech AEV 80 to supply fresh air from the outside to his new room and remove stale air. We ran the supply ducts through two baffle boxes in the attic that vented down into the ceiling. Because Colin's studio is in Colorado we did not need to worry about humidity issues with the ventilation system. 

To heat and cool the room we opted for a Mr. Cool Mini Split, which Colin could install himself. The Mr. Cool runs extremely quiet and is my number one recommendation for soundproof studios, especially budget conscious builds. 

We finished Colin's consulting program by designing and installing his acoustic treatment. I told him to build to giant bass traps in his front corners to help absorb frequencies down to 125 Hz. We added a ceiling cloud and panels on his side walls to create a reflection free zone for mixing and mastering. We added panels along the back side walls and back wall to help reduce reflections. 

In the future Colin can extend a cloud into the back half of his room, add bass traps along his back wall and build or buy pressure traps to help attenuate a room mode he had at 40Hz. 

We used Room EQ Wizard and a measurement mic to make sure his room was dialed in and we used Sonarworks to correct his speakers for any final issues he has in his room. 

In the end Colin says his mixes translate to the car and beyond and he can mix songs with greater accuracy and speed than he ever could before! 

If you want to see if the Soundproof Studio Blueprint is the right fit for you then please feel free to fill out an application here:  Soundproof Studio Blueprint Application. 

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

In my studio I have cathedral ceilings, these may also go under the name vaulted ceilings. When you vault a ceiling you have to worry about moisture issues developing under your roof sheathing. In this article I will describe to of the best ways to design and build a soundproof cathedral ceiling. 

The traditional way to build a cathedral ceiling is to leave a space for an air vent between the underside of your roof sheathing and the insulation in the ceiling cavity. This allows air to pass under the wood sheathing and up through your roof cap vent, which prevents the build up of condensation under your roof. 

The best way to do this is to build soffits under both eaves that allow air to enter under the roof cavity up the vent air space and out through your roof cap vent. This is one of the best methods for venting cathedral ceilings, however, it is not the best method for soundproofing your cathedral ceiling. The reason is that that air circulation means the space above your drywall is open to the outside and sound will easily enter in. 

I will say that I did this system in my studio and the soundproofing is still adequate, however, if I were to build my studio again I would use on of the following other systems to prevent moisture build up under my roof sheathing. 

Another option to prevent moisture buildup under your roof is to use spray foam on the underside of your roof sheathing. This means you no longer need to have an air space and you can close up your roof so that it is airtight. With soundproofing we always want our systems to be airtight. Using spray foam allows us to seal the entire roof cavity so sound will not enter. 

It is important to use closed cell spray foam. I also highly recommend you hire a professional who does this daily so that the job is done quickly and correctly. You want to make sure that the spray foam never touches your hat channels, acoustic clips or drywall. 

The third option to prevent moisture buildup under your roof sheathing is to add rigid insulation on top of your roof sheathing before you apply your shingles. This method will prevent the buildup of moisture under your roof. 

As with spray foam I highly recommend you find an experienced professional to install the insulation. Any small gaps in the insulation could lead to water damage over time. 

If you want vaulted ceilings in your soundproof room make sure to use one of the methods I recommended above. Remember option 2 and 3 will give you superior soundproofing while option one may arguably give you better water vapor protection.