A vocal booth is a great way to allocate a small space in your studio to record one or two people. It keeps room anomalies at bay and prevents external noise from polluting the vocal tracks.
But how small can a vocal booth actually be?
The smallest vocal booth for practical use in home studios can be as tiny as 4 ft. x 4 ft. It can accommodate one person playing a small or medium-sized instrument or two vocalists. However, such a small booth is susceptible to room resonance and comb filtering issues. It might suffice for voice-over work but won’t deliver exceptional results for vocals.
Vocals are integral to every composition as they draw the most attention towards them.
It’s the catch chorus or mesmerizing melody that grabs an audience’s attention, becoming a selling point of every song. That why vocals are placed in front in a mix and command the spotlight on stage.
No one likes to deal with the lopsided reverb or wayward room reflections in a vocal track.
Vocal booths need to be large enough to avoid room resonance. The male vocal frequency range is 150 Hz to 300 Hz and female vocals have a frequency of 200 Hz to 500 Hz. 500 Hz, or a ratio of 500 cycles that have a 0.002 second reflection period and travel a little over 2 feet (27.12”).
If the math is confusing you, I’m trying to imply that a vocal booth should be wide enough to prevent room resonance and inhibit a sound from adding to itself.
Before we explore the smallest possible size and the reasons for it, let’s brush up on what a vocal booth does.
Vocal Booth 101
A vocal booth is a room within a room that eliminates unwanted reverb and reflections from the recorded audio.
These booths are commonly found in small-sized or home recording studios. Vocals are the primary reason people create them but are also used to record guitar or bass cabinets or other basic audio recordings.
They can also be an alternative to isolation booths for recording artists and music producers who are short on cash or real estate. But it isn’t uncommon to find them in professional studios, especially those who want a space for vocals while recording live bands or ensembles.
The first step to create one is to decide the spatial specifications and portion them off.
Then you need to figure out how to isolate them using some form of acoustic treatment. The primary goal is to absorb the whole vocal frequency range on the inside and isolate sound from the outside.
This brings us to the actual dimensions of a vocal booth. But it is important to figure out your needs and budget before you get into that.
A booth can vary in size. It can be as small as 4’ x 4’ or as big as 12’ x 12’ and larger. Based on individual needs, people use acoustic foam, tiles, or other acoustic treatment to cover 50% to 80% of the booth. It is advised to go for something as big as your budget and space allow.
Two other options can be useful for recording:
- Portable Vocal Booths: Portable vocal booths are makeshift structures or shield panels placed in the vocal recording area to provide some degree of isolation. The sE Electronics Reflexion Filter is a good example of a shield panel. It is placed behind the microphone in an untreated space to diffuse the sound waves around the microphone.
People also use makeshift structures made from Rockwool/timbre panels or pre-fitted mobile acoustic vocal booths that have a metal frame draped with sound-absorbing material.
- DIY Vocal Booths: These can be either made from mattresses, thick blankets, or curtains. Some ingenious producers also make a lightweight frame and drape it with acoustic panels or sound-absorbing materials.
If you want the requisite quality, you need a good amount of absorption. This varies between 70 to 80% coverage based on the size. Larger booths also need bass traps in the corners for absorption while smaller rooms can be fitted with large absorption corner panels.
- I have even written an article on recording vocals in a car! You can read it here
How Small Can A Vocal Booth Be?
Vocal booths can be as small as 4′ x 3′ or 4′ x 4′ with a ceiling height of 8feet in tight spaces. However, the end-user has to design it based on the requirements. Space and individual needs are subjective. Small rooms can work for voice-over needs but a tiny space is not suited for recording vocalists or instruments.
Small booths need good sound isolation to solve sound refraction issues.
Lightweight materials (panels or tiles) absorb/deflect high frequencies. You need heavy acoustic tiles if you desire deep and resonant vocals. We’ll discuss this in more detail in the next section.
If cost and space are not prohibitive, you should build a booth with the largest practical dimensions you can spare in your recording environment. For example, you will need a larger booth if you wish to record someone playing a guitar or keyboard and singing at the same time.
Although there is no consensus on a be-all and end-all dimension, many experts suggest that 5’ x 6’ x 11’ is the smallest “practical” size for recording high-quality vocal tracks.
The Disadvantages Of A Very Small Vocal Booth
Small vocal booths need a minimum of 4-inch thick absorption with 6 or 8-inches being ideal.
The barrier material and treatment will vary based on the levels and source location of outside noise. For inside noise, you need some additional large panels in the corners where the wall meets the ceiling. In other words, vocal booths need massive coverage and deep treatment.
Typical foam panels aren’t very effective in eliminating the low-frequency buildup that is common in small rooms. Subsequently, they tend to sound boxy and accentuate the low mids around 200 – 250Hz to create a ‘chest hump’ effect in the vocals.
Additionally, tiny rooms demand a lot of bass traps and rigid fiberglass panels to sound half decent.
It is hard to accommodate bass traps in a 4’ x 4’ booth because every inch counts when there is already such a dearth of space. Plus, the bass traps should be 5 to 8 cm away from the walls.
Once you factor in the size of thick panels in the inner dimensions, you are left with very little room for a mic + stand + performer. The booth won’t be able to comfortably host a vocalist who plays the acoustic guitar simultaneously. Worse yet, it can feel constricting and claustrophobic.
In other words, don’t expect miracles from a 4’ x 4’ vocal booth with 7 to 8 feet height. Do what you may, they will never sound or feel like a proper recording room with wall/ceiling separation and acoustic treatment.
Take a look at this video that shows how to make your own vocal booth.
How Much Does A Vocal Booth Cost?
The cost of a vocal booth varies based on size, material, and accessories.
It can range from $500 to $5000+ for small to medium-sized home studios. You can find cheaper solutions if you are willing to research DIY setups and build them from scratch.
However, DIY vocal booths are not a professional solution unless you have a solid understanding of acoustic principles.
Vocal booths are not better or worse than the natural sound recording in a room with proper acoustic treatment.
The recordings from a good vocal booth are clean and controlled whereas the room has its only unique sonic character, both of which can work depending on the context.
Without delving into the technicalities, I’ve tried to explain the basic concepts of vocal booths and their dimensions. This endeavor, however, requires some knowledge of acoustic materials, sound (refraction), and a keen desire to experiment until you find something that works for you.