How to Build a Soundproof Room Within a Room

If you’ve had external noise ruin your recordings, you know how frustrating it can be. Sound isolation is probably the number one reason people start to wonder how to build a soundproof room within a room.

Your options when building a soundproof room within a room are traditional construction or a portable booth. For the former, you frame in walls, leave room for insulation, and use drywall to finish. You also have to isolate the ceiling and floor. A booth can use different materials to achieve sound dampening in less space.

As you can imagine from just the basic description, both of these are pretty major undertakings. Let’s look at why you’d want to build a soundproof room within a room, why you might not want to — or, indeed, be able to — as well as some alternatives and then dive into how you can build your soundproof room within a room.

Why Build A Soundproof Room Within A Room?

We’ve already covered the first reason: sound isolation. That works in both directions.

A soundproof room within a room will block out external noise to anyone in the room and keep the noise made in the room from getting out, as well.

That’s useful for recording any kind of audio and video, and makes a good practice space, as well.

Why Isolate Sound

Sound isolation is the process of blocking sound from traveling to unwanted places.

A sound-isolated room will prevent noise from coming in or out, to an extent. Please keep in mind that with sound isolation, you can only make improvements, you can never fully achieve it.

The room within a room concept is even used by recording studios to create their recording spaces, so it’s clearly among the most effective ways to isolate sound.

There is no such thing as true sound isolation, but different approaches can help enormously. Sound isolation involves processes like filling air gaps, and building second walls or floors, to minimize sound bleed.

Another aspect of sound isolation is the use of sound absorbing materials, from special kinds of wall insulation to particular kinds of glue and the use of rubber and foam to isolate walls, floors, and ceilings from transmitting sound through contact.

Sound, after all, is vibrations in the air. The way to isolate sound is to slow down and eventually stop the vibrations.

It takes more material to stop lower frequencies than higher ones, which makes building a soundproof room within a room a balancing act between how much sound you can dampen in the space available.

What Is Acoustic Treatment?

Acoustic treatment is the process of controlling how things sound within a room. This is important for recording or for mixing music.

Recording in an untreated room will add an unnatural sound to the recording. You can hear as sound waves bounce off of random surfaces and give a strange reverb effect.

For mixing music, it is crucial to hear music as it truly sounds. When listening back to mixes on monitor speakers, an untreated room once again reflects the sound in unnatural ways.

Acoustic treatment will control the unwanted reflections, so all you hear is the sound coming through your monitors.

It’s important to untangle these terms, because building a soundproof room within a room is a sound-isolating move.

To ensure you can record or mix in that space, you also need to consider acoustic treatment, which is a little beyond our scope today.

We’ve covered making your own bass traps before, which is a good place to start with acoustic treatment.

If you’re considering doing your own acoustic treatment, this video gives a comparison of the sound absorbing qualities of various common DIY solutions.

Why Shouldn’t You Build A Soundproof Room Within A Room?

There are a lot of reasons someone might shy away from building their very own soundproof room within a room.

One obvious reason is cost. Even a “budget” DIY-style build will cost hundreds and possibly thousands of dollars in materials alone, plus the time it will take.

And if you live in an apartment or rent instead of own, you want to proceed very cautiously if you think you want to build a soundproof room within a room. The traditional methods could involve changes to the building where the room within a room is being built, including holes in the floor or ceiling.

Even a less traditional design, like a booth large enough to stand up in, might not work in an apartment, depending on whether you can get it in and out, how much weight it will add to the floors and other considerations.

In short, if you’re renting, you want to ask before doing anything, and don’t be surprised if every request you make is met with a “No.”

Another reason someone might not want to build a soundproof room within a room is they’ve decided they can use something like a truly portable vocal booth instead. This video reviews one such booth and gives examples of how effective it is at producing a “studio quality” recording.

They could also have tried any of a variety of stopgap solutions that gave them good enough sound.

Simpler Alternatives To Building A Soundproof Room Within A Room

If you notice just a little bit of outside noise bleeding into your recordings, you might well be tempted to try something short of a full soundproof room within a room or even a vocal booth.

Here are a few places to start.

Air Gaps

A lot of sound travels through air gaps, particularly higher-frequency sounds.

The perimeters of doors and windows, electrical outlets, the room’s corners, spaces between drywall panels — all of these could have gaps.

Green Glue is the name to know in acoustic caulk, and their sealant is designed for just this purpose. (Be aware that Green Glue Noiseproofing Compound is different. It’s used for sealing the spaces between double drywall construction.) Use Green Glue’s sealant to fill in any potential air gaps, and you should notice the difference.

Doors And Windows

You should try sound isolating weather stripping to create airtight seals at window and door openings.

There’s also a good chance your door is hollow, especially if it is an interior door. Denser materials block far more sound, so consider replacing it with a solid core door exterior door.

Exterior doors are also thicker, so be aware that if you are replacing a door with a thicker one, you may need to move the hinges and/or striker, which is where the latch closes into the frame.

Also consider a fabric or plastic door sweep to seal the air gap below the door.

You can further sound-isolate your room with a few more steps that are far simpler than building a room within a room.

Using wood, sound-isolating material, sound isolating insulation, and handles, you can create “plugs” for your windows that can be placed in the window frames whenever you want to block sound, but removed whenever you miss the sun and the outside world.

Many blackout curtains also advertise sound isolation on top of light and temperature isolation. Try hanging these over your windows!

Finally, covering one side of your door with sound-dampening material can help block sound from entering from the outside world.

Off The Rack Solutions

We already mentioned the IsoVox portable vocal booth earlier as a solution some people might choose. While that uses a box you essentially wear to mimic the isolation of a studio, other companies offer what amount to larger versions.

There are multiple companies that sell what amount to tiny, mobile soundproof rooms. Companies like Room pitch their smallest model, called the phone booth — which should give you a good idea of its size — as a way to give 28 dB of sound isolation in an office. It would obviously do the same for a recording, but, just like with a sound isolating room, that wouldn’t including acoustic treatment to make the space right for recording and mixing, though options like that are available.

Another company, WhisperRoom, offers similar products. Lined with acoustic foam and coming in as small as 3.5 feet by 2.5 feet, they’re pitched as portable sound isolation booths and can also be outfitted with various kinds of acoustic treatment.

You can definitely build something like this, and we’ll look at how shortly, but if you don’t have the time or know how, the off the rack solutions start around $5,000.

Building A Soundproof Room Within A Room

It’s difficult to write a one-size-fits-all guide because there are as many potential room-within-room designs as there are musicians.

Each musician has different musical needs, different sound isolation needs, and different rooms they are building in, after all.

But there are some basics that will guide you on how to build your room within a room to meet your specific needs.

No matter how you’re choosing to tackle this project, a few concepts and materials are probably going to come in handy no matter what.

A room within a room blocks sound in a couple of ways.

For one, you are creating more space and material for sound to travel through — an extra layer of floor, ceiling, and wall, as well as insulation.

A room within room built to isolate sound is also usually “floating,” meaning they are not attached to their surroundings in typical ways.

The floors or walls often employ some kind of rubber or foam layer between the outer and inner room, such as Auralex U-Boat Floor Floaters, Platfoam foam strips, or Platsheet foam panels.

The room within a room is also likely to use acoustic-dampening insulation such as Roxul Rockboard. Double layers of ⅝-inch drywall are common for the inner room’s walls, and Green Glue Noiseproof Compound is used to seal the drywall.

A booth usually uses rubber, foam, cloth, and other sound absorbing material over some kind of frame. Isolating the booth from the floor of the room it’s on is key to good sound isolation.

Traditional Construction

One way to build a soundproof room within a room is a very traditional construction method: Frame walls with studs. To make the room as isolated as possible, build an inner and outer frame from 2×4″ construction lumber. Space the frames as far apart as you want, keeping in mind that a larger gap will absorb more sound, and connect the top and bottom.

You need to build a platform for the floor of the room. That can be as simple as a foam or rubber sound-absorbing underlayment layer covered by some kind of flooring to multiple layers of plywood insulated by sound-absorbing underlayment layers and Green Glue to seal everything together.

You have the same issue for the ceiling as you did for the floor, with the added concerns about headroom. If you’re enclosing a large room this way, you could remove much of the room’s original ceiling and install a drop ceiling with acoustic tiles.

That, plus adequate insulation would help with sound isolation from above.

If you’re not covering as large of a space, or you don’t want to, aren’t allowed to, or just can’t get into the ceiling, you could consider layers of plywood with sound absorbing material sandwiched between them, similar to the floor.

You just have to be sure to keep your walls short enough that such a panel will fit.

Put the wall frames on the panel you built for the floor and attach the ceiling panel. Fill the air gap with insulation and, as noted above, double layers of ⅝-inch drywall are a great choice for interior walls.

You need some way in and out — consider framing in space for a solid-core door in one wall and using sound-absorbing material to line the inside and outside of the door.

If all of this sounds like a lot of work, you’re right, it definitely is.

Vocal Booth Construction

If you want a somewhat simpler build, you can try building a vocal booth. Similar to the off the rack sound isolating rooms, these are portable — more portable than an actual room, at least! — spaces to help block out sound.

The most basic method is to create a frame and use sound isolating materials for the walls. The simplest of these is a PVC frame you can stand.

You drape the pipes in sound absorbing material and cover the entrance when you’re using it. If you don’t isolate the floor in some way this will be less than perfect, but you generally don’t have to worry about damage to the room’s ceiling.

You can build a platform as above or even just set the frame on a layer of sound-absorbing material.

A more substantial build — and one that’s more effective at isolating sound — would use MDF panels covered in sound absorbing materials to create the walls and use a small platform for a floor, with a panel for a ceiling similar to the one described above

Materials You Need To Build Your Own Soundproof Room Within A Room

What you’ll need to build your soundproof room within a room will vary based on your approach, but here’s a quick rundown.

Detailed Guides

When building a room within a room, though, you will probably have to do fairly extensive research. Most projects involve a combination of approaches, taken from different sources, to create the final product. While researching, some of my favorite articles were:

• Sound-On-Sound’s guide to room-within-a-room construction, for general principles.
• Primacoustic’s guide on vocal booth construction has some great notes on different approaches to stud construction, as well as the effects of a small room on vocal sound (and how to address that.)

Conclusion

I totally understand if building a soundproof room within a room sounds like way too big an undertaking. It’s not easy, and it definitely won’t work everywhere.

With that said, the option of a portable booth made of PVC pipes covered with soft sound-absorbing material is not very expensive, at least relatively speaking, and it can be done pretty much anywhere you have room for it.

Such a design is far from perfect when it comes to sound isolation, but it might be the right balance of easy to make, easy to use and effective for some people.

It’s just one of a range of solutions out there, from the simple and inexpensive to the complex and costly, based on how much sound isolation you need and what you have at your disposal.

Robert Ruby

Robert is a freelance audio engineer and the lead writer for Range of Sounds. Robert has had a lifelong obsession with dissecting and understanding music and is a self-taught composer, multi-instrumentalist, songwriter, singer, and recording engineer.