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Primacoustic FlexiBooth (grey)

The FlexiBooth is a full size 24" x 48" wall-mounted acoustic cupboard that opens up to surround the vocal talent and create a dry 'voice-over zone. The innovative design separates and attenuates room ambiance from the voice recording, which then allows the engineer to add echo or reverb and equalize the voice to best suit the performance in post production.

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Category: Recording:Acoustics:Studio Gobos


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From the outside, the FlexiBooth looks like a typical cupboard. It features an attractive black melamine finish that is easy to clean. Inside, ultra high performance 6lb per cubic foot glass wool panels effectively absorb sound throughout the voice range. The acoustic panels are 100% encapsulated with micromesh and are covered in a tough yet attractive acoustically transparent fabric to enhance the fit and finish. Because of the heavy construction, sound attenuation is excellent.

The FlexiBooth can also be used as a variable room ambiance controller. Those that have recorded in large professional studios will be familiar with the variable acoustic panels that are often used to tailor room acoustics. For instance, a brighter more ambient room is generally preferred with acoustic instruments while a darker ambiance is often preferred for voice, electric guitars and so on. By positioning several FlexiBooths around the room, one can easily create different acoustic environments by simply opening or closing the FlexiBooth doors.

The Primacoustic FlexiBooth provides a simple yet highly effective solution for vocal recording that can adapt to any room. The FlexiBooth ships flat and assembles in minutes using common household tools.

The Science Of FlexiBooth
If you think about it, common sense tells us that placing a single absorptive panel on the wall of a gymnasium will have zero effect on the acoustics in the room. At the other extreme, covering the walls and ceiling will render a room completely dead. Simply stated, the greater the absorptive surfaces one applies to a room, the more energy you will take out. If you remove the ambience from the room and make it acoustically 'dead', you can then 'electronically' add the ambiance later in post production. This, in fact, is the basis behind what is commonly known as a voice-over booth.

Today, voice-over booths are used in all kinds of audio production. A common application is in the studio for recording a voice such as a lead singer of a band. Another is voice over for film and TV post production. This extends into ring tones, computer animation sound tracks, and on-line pod-casting. In the majority of these situations, the intent of a vocal booth is to take away the rooms 'personality' so that you can add the 'desired character' electronically to fit the scene. In other words, you start by recording a voice without any ambiance and add echo to make it sound like you are in the Grand Canyon, excessive hall reverb to sound like you are in a gymnasium, or maybe just a touch of echo and a smattering of reverb with a dark EQ to sound as if you are in a dark back alley.

The Typical Vocal Booth Design
Traditional vocal booths are usually small isolation rooms that are completely covered with acoustic panels. The intent is to completely surround the vocal talent with absorptive panels while isolating the vocal microphone from other instruments or street noise. Better isolation rooms are made using heavy walls with high quality absorbers and are usually very expensive.

Although most vocal booths do a good job at controlling noise and eliminating ambiance, they are not without problems. Most employ a thin layer of acoustic foam that is only effective at absorbing upper frequencies and therefore tend to make the voice sound boomy. This is due to the combined effect of the room geometry, subsequent room modes and the lack of low frequency absorption. The good news is that this problem can easily be addressed by adding a couple of bass traps like the Cumulus in the tri-corners.

The FlexiBooth
For those that do not have the space or budget for a full size voice-over booth, the FlexiBooth presents a viable alternative. The design begins using the same concept as a voice-over booth whereby three full size acoustic panels surround the talent with an acoustical barrier to create a dry acoustic zone. This contains the voice within the absorptive zone and reduces the spill from exciting the room. And since the doors are made from heavy MDF board, these block much of the room ambiance from re-entering the microphone which would otherwise affect the dry recording.

What sets the FlexiBooth apart is the quality of the acoustic absorbers. Unlike open cell acoustic foam that is practically useless at absorbing low frequencies, the FlexiBooth employs high performance 6lb per cubit foot glass wool panels. The main absorptive panel is made from 2" material while the side door panels employ 1" material. These combine to provide even absorption right down into the lower voice range.

The Problem With Vocal Booths
The Flexibooth's hidden advantage is the lack of closed boundaries. As previously described, the problem with most vocal booths is that they are small and generate unwanted resonance in the lower mid range. Because the FlexiBooth is generally placed within a larger room, the resonant frequencies are at a much lower frequency which makes them much less prominent and easily equalized out of the audio track by simply using a high pass filter. Not only does the FlexiBooth do a better job at absorbing the voice energy, but also avoids the chest hump problem that plagues most voice-over booths. Very cool!

To demonstraight this lets compare the axial room modes for two rooms. We can calculate the lowest (and most powerfull) room mode by dividing the speed of sound at 1130 ft/per second by each room dimension. The first room is a small vocal booth measuring 4' x 5' x 8'. This small room will naturaly resonate at 141Hz, 226Hz and 282Hz. The axial modes for this small vocal booth are not only packed closely together they cover the complete low range of the human voice.

The second room is an average sized residental type room with 10' x 12' x 8' dimensions. Using the same math this larger room shows modes at 141Hz, 94Hz, and 113Hz. These modes are spread out over a wider range and two out of three are below the male vocal range making them much easier to deal with using acoustic treatment and electronic filtering. At the same time the FlexiBooth give you the same dry sound as the smaller vocal booth.

Variable Acoustic Control
Another cool benefit is using several FlexiBooths together to vary the room's acoustical character. By simply opening or closing the cupboard doors, you can brighten or darken the room depending on the sound you are after. For instance when recording acoustic instruments, you could close the FlexiBooth doors to create a more live environment. When recording drums, you could deaden the room by having all of the doors open. This of course is where we got the prefix Flexi from it is just so wonderfully flexible!

How To Use The FlexiBooth
The Primacoustic FlexiBooth is a unique device that can instantly turn any room into a very functional vocal recording environment simply by opening the doors.

The FlexiBooth features an innovative 24" x 48" cupboard cabinet design that hangs on any wall surface. When the doors are opened, a deep 2" high density Broadway panel fills the back of the cabinet while low-profile 1" thick panels line the doors.

This creates a 16 square foot area that effectively absorbs sound throughout the voice range, making the FlexiBooth ideal for voice-over, vocal tracking and podcasting. The frame and doors are constructed with black MDF and assembled using screws, cam locks and wood dowels. Shipped flat to save freight, the FlexiBooth takes about 30 minutes to construct using household tools.

Wall mounting is done using a simple 'French cleat'. The cleat mounts to the wall using the included drywall anchors and screws. Once fastened, the FlexiBooth simply hangs in place like a picture. The cleat features opposing beveled edges that lock the FlexiBooth in place for a secure hold.

Instant Voice-Over Booth: The innovative cupboard design allows the FlexiBooth to be closed when not in use and then opened in seconds when the vocal talent arrives. A microphone is placed in front of the artist and a vocal sheet is easily pinned to the surface for lyrics. Opening the doors to different widths will change the sound by allowing more or less room ambiance into the microphone.

Variable Room Acoustics: The FlexiBooth also presents the studio with the option of applying variable acoustics to the room's environment. For instance, opening the cupboard doors to fully expose the absorptive panels will reduce the room reverberant field while closing the doors will increase the room reflections. For instance when recording an acoustic guitar, you may want to increase the natural reverb in the room while decreasing the reverb may be more suitable for an electric guitar track.

Stand Mounted Gobo: Some innovative FlexiBooth users have constructed simple H shaped stand on which the FlexiBooth is mounted. This turns the FlexiBooth into a studio gobo which can be used to control bleed between instruments. If you intend to use the FlexiBooth this way, make sure that the stand is sufficiently large to hold the weight and deep enough to ensure the FlexiBooth will not fall over when the doors are extended.

Product Features:
  • Creates an instant vocal booth in any room
  • Full size 24" x 48" design really works
  • Remarkably effective at controlling room ambience
  • Easy to mount 'French-cleat' sets up in minutes

Product Specifications:
The FlexiBooth is an acoustic cupboard that measures 24" x 48" x 4" deep. The outer shell is constructed using heavy black MDF board. When open, it exposes three Broadway acoustic panels.

The main wall panel is 2" thick and measures 24" x 48" while the two side panels are 1" thick and measure 12" x 48". All three acoustic panels are made from high density 6lb per cubic foot glass wool and fully encapsulated with micromesh and resin hardened edges for a clean look. Panels are the covered in an acoustically transparent fabric and come in choice of grey or beige.

The Broadway panels provide balanced absorption throughout the voice range. Low frequencies are further extended when the FlexiBooth is mounted on the wall as the design introduces an air gap behind the main panel.

Once in place the door glide hardware is used to hold the doors open at several pre-set positions allowing you to tailor the amount of off-axis reflections that reach the microphone. When not in use magnetic door catches keep the doors shut and out of the way.
  • Frame Material: Black melamine laminated MDF
  • Dimensions: 24" x 48" x 4" / 609mm x 1219mm x 101mm
  • Panel Material: Formed, semi rigid inorganic glass fibers; Density 6.0 lbs. pcf. (96 kg/m)
  • Fabric Facing: Acoustically transparent polyester
  • Fabric Color: Grey