When you think about soundproofing there are two factors to consider: exterior sound, and interior sound. First and foremost, whenever possible you want to put as much padding and distance between you and the outside world. I’m going to be covering a fair amount of materials in this post, so rather than wreck the flow, I’m going to post all the links at the end. If you’re setting up a Converted-Closet Studio, you might want to start by putting up a layer of “Airguard” or a similar underlayment. If money is a Factor, you could also consider using cork underlayment, for about half the price. And of course, the Bargain Basement option is to use heavy blankets scavenge from your local Goodwill or other charity store. As is always the case, the less money you spend, the less effective your overall outcome will be. If you’re renting rather than owning the space you’ll want to consider using industrial staples rather than drywall screws when affixing the underlayment to the wall. As they say, “Start with the end in mind.”
After putting up the initial layer of underlayment, it’s time to choose the inner layer. Ideally, this should be made entirely of plywood. Once again, the thicker the wood, the more it will insulate you against outside noises. For the most cost-effective option, you could opt for particle board which runs about 50% of the cost per square foot as that of regular plywood. Don’t forget, that everything you’re putting up on the interior walls must also be done to the inside of the door! It would be awful to do all this work only to have a bunch of noise come in through some crappy hollow-core closet door.
Finally, if you are building this in an apartment, be mindful of the ceiling and the floor. It makes no sense to put additional material down on a concrete floor, but if you are living in an upstairs apartment, additional layers may be necessary. The same for your ceiling if you have neighbors upstrairs. The ceiling may not require a full layer of external soundproofing, but would most likely benefit from a single layer of insulation and drywall. As always, use your best judgement.
If you choose to build your studio as an exterior structure, be sure when finishing the interior to use a single layer of insulation and a layer of damping compound between two layers of 1/2” thick drywall. Hang the first layer of drywall., then apply the compound, followed by the second layer of drywall.
Now that we all have a room with a finished interior, it’s time to talk about dealing with inside sounds. If you were to Simply to leave the walls bare, every noise would bounce around the walls and ceiling like a pinball in an arcade machine. There are basically two options for dealing with this problem. Composed of compressed foam, sound absorbing acoustic panels “catch” sound waves to reduce general noise, clarify speech, and limit reverberation in enclosed areas. When sound waves travel through the air and strike wall or ceiling- mounted noise reducing panels, the foam pores vibrate, increasing friction. These vibrations quickly reach a point where enough friction is created for the conversion of sound energy to kinetic energy, which is simply the energy of an object in motion. Since kinetic energy can’t be contained, it dissipates quickly, leaving no sound waves and, no sound. The only problem is that acoustic panels can be expensive depending upon how many you require, but they are truly the best solution for absorbing sound interior. I’m not going to go into all of the options here, but suffice it to say a quick Google search should give you a wealth of further information on acoustic panels.
The other option is to cover the entire interior space with a different sound absorbing material. I chose the least expensive, high traffic, shag carpet from my local carpet supply store. I then cut it (always measure twice!) and attached it to the walls using industrial strength wallpaper paste, with a few drywall screws at the top to get each piece started, then finished each piece with a staple gun. This was not only a cost effective solution, but its also very effective, as it provides one more layer of soundproofing from outside noises, and there is literally no surface left from which a sound can reverberate.
Soundproofing Underlayment: https://www.homedepot.com/p/Roberts-AirGuard-630-sq-ft-40-in-x-
Cork Underlayment: https://www.homedepot.com/p/QEP-200-sq-ft-1-4-in-Cork-Underlayment-Roll-
Damping Compound: https://www.greengluecompany.com/products/noiseproofing-compound
Acoustic Panels (cheap): https://www.walmart.com/ip/12-24-48pcs-Acoustic-Panels-Sound-Proofing-
Acoustic panels (expensive): https://acousticalsolutions.com/product/alphasorb-pro-acoustic-panel-
Carpet Example: https://www.stainmaster.com/Carpet/products/details/MCP0011205-COL0096899