So, in Part 1, we went over the overarching process to constructing a solid rock and roll den. (You should read that first). Now we dig into the more nitty, gritty aspects. Sooooooooo, lets start off with the NUMBER ONE MOST IMPORTANT PART OF THE WHOLE BUILD.
Isolation Basics and Planning
Lets get something out of the way right now. Nailing up egg cartons, foam, mattresses, carpet, etc. on your walls does nothing for sound isolation. It will absorb certain frequencies, and change the way the room sounds inside. However, your neighbors will still call the police on you. Got it? Good.
The most important aspects of isolation are mass, decoupling, absorption and sealing. There are other factors, but those are the biggies. I’m not going to get into the science of it. That’s been covered in great detail all over the Interwebz. If you want to get more information on that, check out the posts at Soundproofingcompany.com. I used their articles as a reference for my own build, and they do a great job of explaining how isolation works.
Number 1 Absorption:
A hollow wall is bad. This part is pretty obvious. Pretty much everyone knows that an insulated wall transmits less sound than an uninsulated one. This is because the air cavity inside will vibrate and pass sound to the other side of the wall. Standard fiberglass insulation helps by absorbing these vibrations.
Number 2 Mass:
Mass is your friend. The heavier and more dense your wall, the more difficult it is for sound to penetrate it. This because it is more difficult to vibrate a heavy wall than a light one, and sound is just that. A vibration. Every time you double the mass of a wall, you reduce the sound transmission by half.
There are many ways to build a high mass wall, ( concrete, bricks, MLV, etc.) but the most cost effective method is a wood framed wall, and layering drywall. I personally used two layers of 5/8″ drywall in my build.
Number 3 Decoupling:
Sound travels through solid structures. When wall building materials are directly mounted to one another, as they are in traditional construction, sound waves pass right through from one surface to another.
Decoupling breaks this link, and minimizes the vibration transfer from one surface to another. There are a few techniques for this, but we are focusing on the double wall/room within a room method.
Number 4 Sealing:
This part is so crucial. Your room MUST be properly sealed or all your efforts will be for naught. The heaviest, best constructed wall does nothing if there is a hole in it for sound to leak out of.
And by properly sealed, I mean every single seam must be filled with acoustic caulk. All of them. Pretend that you are attempting to make this room hold water. Acoustic caulk is critical because it stays permanently flexible, which is what you want.
This was the big downfall with my project, and I urge anybody considering undertaking this to take the time and plan everything carefully. My building was originally going to just be a man cave/hangout area. It was going to be insulated and heated, but that was the extent of it. As such, I built a wood floor to start. Huge mistake. If I would have poured a slab, the Tone Cave would easily be twice as isolated as it currently is.
Note- Some local building codes may make a slab unfeasible. My floor is significantly overbuilt and performs adequately, just not as well as a slab. I will detail it’s construction as the final part of the series for those facing such constraints.
There are many additional factors to consider when building with isolation in mind. For instance…..
- Your wall thickness will be at least twice that of a normal building. This will have a large impact on your interior square footage. Size the exterior correctly from the beginning to avoid a cramped space.
- The further your building is away from neighbors/other people who find rock and roll offensive the less money you need to put into the structure. Isolation costs $$ and the less you need, the more Strymon pedals you can put inside it when it is finished.
- If you can tolerate the look of surface mount electrical on the interior, it is by far the way to go. Normal residential wiring requires large holes to be punched in the wall, hence sound leakage. (See Number 4). There are products available to seal these holes, but its best to avoid them all together.
- “Soundproof” is a misnomer. We are shooting for an acceptable level of isolation. For reference, I can rehearse with my band at gig volumes without the neighbors complaining. But you can hear us play from about ten feet away from the practice space. To make it truly soundproof, you are looking at serious money.
- You need climate control of some sort, don’t forget about that! In this application I recommend and use a ductless mini-split heat pump. They both heat and cool, are stupid efficient, stand alone, and make the smallest possible hole in the wall. (There’s that leakage thing again).
- Reduce the amount of openings in the exterior. I recommend no windows, they aren’t worth the cost or the hassle. Unless you buy specialized windows, they will leak sound like crazy. Just install a boatload of lights.
- Unless you want to drop some serious $$ on a specialized door, plan on a double door. As in, you open the front door and you are immediately greeted by another door which you must open to enter. This will be significantly better than a single door.
- Where are you sourcing your material? I did buy quite a lot from the local Home Depot out of convenience. But I saved thousands of dollars by hunting on Craigslist, and researching other local suppliers. For example, I saved $700 on my drywall by using a local supplier over Home Depot. Not only did this save me money, but they delivered the enormous load to my house, and hand carried it to where it needed to go.
That is quite the pile for a 300 square foot building
These are just a few of the many things to consider. This why the planning stage is so crucial, There is nothing worse than doing an enormous amount of work, only to have the plan foiled by an unseen gremlin. Trust me, I know this first hand. It still hurts to think about.
So plan, plan, plan. Plan some more, and plan! It will make the project go 10,000,000,000 times smoother, cost you less money, and deliver better results in the end.
PS- As always, if you have any questions, hit me up at firstname.lastname@example.org, or use the Contact Us form.