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Primacoustic GoTrap (black)

The Primacoustic GoTrap is a combination studio gobo and bass trap that is designed to enhance the recording process by controlling spill between instruments, while passively removing excessive bass from the room.

It features two Broadway fabric covered high-density glass wool acoustic panels mounted on both sides that effectively absorb the sound. This is augmented with a heavy internal MDF board that adds mass to help contain spill between instruments. The MDF board also acts like a low frequency resonator that combines with the acoustic panels and the deep internal air cavity to absorb bass down to 75Hz.

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Category: Recording:Acoustics:Studio Gobos


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Shipped flat to save freight, the 24" x 36" (60.96cm x 91.44cm) GoTrap is made from furniture grade multi-ply Baltic birch and engineered with dovetail joints for maximum durability in professional studio environments. This is particularly important when you consider that gobos tend to be tossed around or stacked to create walls and often employed as a bench for studio session players! Features include side access handles for easy handling and rubber feet to reduce wear & tear. The GoTrap is available with choice of grey, beige or black panels.

This makes the GoTrap an ideal studio device as it will be constantly used as a gobo to control spill from instruments to improve the recordings while quietly working to help control excessive bass in your studio.

The Science Of Gobos
The best recordings are realized when you capture the dynamics, feel and magic of musicians playing together. A problem arises when attempting to isolate the instruments so that you can control the various sounds during the mix process. In a perfect world, one would isolate each instrument by placing the musician inside an isolation booth. Voice is often recorded in an isolation booth for this same reason.

Large studios have often employed isolation rooms to control the drums from spilling into the bass microphone or vice-versa. Although this works, the sound inside a small iso-booth is not always ideal. Drums and bass sound better when recorded in larger rooms with ambiance. Larger spaces give the low frequencies room to develop. And the very fact that you put glass between the musicians does make a difference. There is something organic that occurs when great players vibe together in the same acoustic space.

A common approach is to set up gobos between instruments to create sound dividers. Although not as 'perfect' as isolation rooms, gobos reduce spill while allowing the musicians to perform in the same room. Gobos or 'go-betweens' serve two primary functions: they help control sound from spilling between instruments and if properly designed, they do not cause acoustical problems such as early reflections and phase cancellation for the instruments they are serving.

Up until recently, pretty much all recording was done in professional studios. Because a studio would maybe employ 6 to 8 gobos, the market was relatively limited. This is one of the main reasons that finding good quality yet reasonably affordable off-the-shelf gobos has been difficult. So for years, studios have had no choice but to get their gobos made by local carpenters. If designed properly, home made gobos can work well, but you do have to cover all of the bases.

Absorptive Characteristics
To understand how a gobo needs to be made, you must start by thinking about how it will be used. Gobos are dividers that are placed very close to instruments. This means that if they are allowed to reflect sound back into the microphone, comb-filtering will occur and various frequencies will cancel each other out. (not good for recording). So the gobo cannot be a brick wall, it must be very absorptive. Thin material like carpet will only absorb high frequencies - typically above 2000Hz so this will not be effective for most instruments.

The GoTrap employs two thick acoustic panels with a deep air cavity between them. Quarter wavelength calculations show that this will absorb frequencies down below 165Hz. To augment the low frequency behavior, we have added a 'suspended diaphragm' or spring that acts like a speaker in reverse. Simple yet effective.

Gobo Placement Options
Sound has a nasty habit of traveling through everything. If air passes, so will sound. This means that a gobo will not actually stop sound, but reduce the intensity. It is also worth pointing out that low frequencies are more difficult to control than highs. So what engineers do is build walls around the instruments they wish to contain by stacking their gobos. He next challenge... stability.

The GoTrap has been designed with a large footprint. In other words, it has a large, wide base that makes it easy to stack and relatively difficult to topple over. The last thing you want in your studio is an accident because someone accidentally knocked the gobo over and it smashed the neck on that 1958 Les Paul. This stuff happens. You can also use your GoTraps on their sides to create varying wall heights.

To make the GoTrap easy to move and stack, we opted for hand-sized handle cut-outs on the sides and made it large enough to be acoustically effective, yet not so big as one person could not move or stack one. One can easily stack three GoTraps to create a 6ft (2 meter) wall.

Studio Realities
When we first built the GoTrap prototypes, we made them from standard melamine covered fiber board. This is the material you find in most Ikea furniture and Office Depot desks. Melamine has several wonderful advantages: it is relatively inexpensive, it looks pretty good, it is easy to clean, and since 99% of all the kitchens made use it, there is a ton of hardware designed to make it adaptable. Only one problem; it is not real tough. We had a 'big' guest artist stop in for a visit and when he was testing a Radial prototype with a guitar, he sat on our GoTrap prototype. Yup... You guessed it, it broke. Right then and there it became clear. Gobos get the crap beaten out of them and if they are not built really well, they will break.

This prompted us to redesign the GoTrap using Baltic birch and dove tail joints. For eons, speaker manufacturers have built concert loudspeaker using Baltic birch as the extra laminations coupled with the hardness of the wood make it virtually indestructible. The GoTrap's dove-tail joints proved to be the most rugged joint we could deliver plus they look so darn sexy! Now the down side to this process is that this costs more... But we felt that since the GoTraps will likely be a lifetime investment, most studio owners will want a product that is designed to last.

Options & Additions
Many studios have carpeted floors. But many also have wood. This prompted us to add rubber feet for the bottom of the GoTrap to help reduce floor scratches. Some have asked if you can add casters to the GoTrap to make moving them around easy. The answer is yes. Go to your local hardware store and get yourself some good casters with proper nuts & bolts and you are set to go. Just keep in mind that you may want to keep some of your GoTraps without wheels to make stacking easier.

How To Use The GoTrap
GoTrap is a studio gobo that helps control spill between instruments. It is designed to be used on its own or stacked to create a temporary isolation wall. The 24" x 36" (60.69cm x 91.44cm) size was chosen to make handling easy while being large enough to be effective.

Shipped flat to save on freight, the GoTrap assembles in about 15 minutes using standard household tools and glue.

Isolation Wall: Create an isolation wall by stacking GoTraps. Not only will the bleed from the guitar amp be reduced but the other musicians will be more comfortable while recording. You can stack the GoTrap vertically to create a 66" (1.68m) high wall, or horizontally for a 48" (1.21m) high wall.

Spot Isolation: For even greater isolation and separation between instrument mics move a few GoTraps in close around an amplifier. This will not only cut down on the amps sound bleeding into other open mics but will also keep room ambience from entering the amp's microphone.

Instant Vocal Booth: In some situations there may be no vocal isolation booth available. Sometimes there is a vocal booth but it's to small to hold more than one singer, forcing backup singers out into the main room with the drums and guitars. The GoTrap can be called into service to provide isolation for the vocal microphones and make the signers more comfortable next to loud instruments. Call it an instant vocal booth.

Product Features:
  • Reduces spill between instruments
  • Full size 24" x 36" design can be stacked
  • Baltic birch construction with dove-tail joints
  • Choice of black, grey or beige

Product Specifications:
GoTrap is a studio gobo designed to control spill between instruments that also acts as a combination broadband absorber and bass trap to help control excessive bass. Sound control is achieved by combining three acoustical principles into a single device:
  1. To handle lower mid-range and upper frequencies, a set of 2" thick absorptive panels are mounted on the front and back. These are made from 6lb per cubic foot high-density encapsulated glass wool for maximum absorption.
  2. Between the acoustic panels is a rigid membrane that acts as a sound block to control spill while also naturally resonating at lower frequencies. This helps absorb low frequency bass while providing sufficient mass to contain sound.
  3. An 8" air cavity between the acoustic panels is created by the plywood enclosure. This creates a natural bass trap that serves to further attenuate bass in the troublesome 100Hz region.
The GoTrap enclosure is made from Baltic birch plywood with dovetail joints and a durable natural finish. The GoTrap ships flat to save on freight and final assembly is performed using simple household tools in about 15 minutes from start to finish!
  • Frame Material: Baltic Birch plywood with locking dovetail corner joints
  • Dimensions: 24” (609mm) x 36 ” (914mm) x 10 " (254mm)
  • Panel Material: Formed, semi rigid inorganic glass fibers; Density 6.0 lbs. pcf. (96 kg/m)
  • Fabric Facing: Acoustically transparent polyester
  • Ridgid Membrane: 3mm hardboard
  • Fabric Color: Black