Flexi acoustic panel with adjustable wooden slats

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Flexi Acoustic Diffuser

We also offer custom sizes.

Dimensions:

• 120x60x18 cm

• 104x60x18 cm

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Colors:

Flexi Acoustic Diffuser

Colors Available:

• Black

• White

• Dark Oak

• Light Oak

Product Details:

• Adjustable diffuser lamella and sound absorber – all in one.

• Eliminates rattling echoes and standing waves.

• Allows for adjusting the angles of the diffuser lamellas.

• Ideal for recording studios, hi-fi and media rooms, and home theatres.

What is the Flexi Diffuser?

The Flexi Acoustic Diffuser is an innovative acoustic device that combines sound diffusion with sound absorption. It simultaneously regulates high-frequency echoes and reflections.

The diffuser-absorber, typically sized at 120x60x20 cm, features 6 adjustable diffuser lamellas. By rotating these hardwood lamellas at various angles, it diffuses both high and low frequencies, ensuring a balanced energy spread that adapts to the room’s acoustics.

Behind the lamellas, there is a high-density sound-absorbing panel, 6 cm thick, which absorbs directed energy efficiently up to 300 Hz, while also creating resonance among the lamellas.

What Material Are They Made Of?

The Flexi Diffuser is surrounded by hard and heavy blockboards for high durability. The built-in sound-absorbing panel contains high-density acoustic wool embedded in a 2 cm thick wooden frame, targeting the critical low and mid-range frequencies. With a thickness of 5 cm and a density of 90 kg/m³, it effectively absorbs sound in these critical frequency ranges.

Quick Positioning:

It is recommended to position the Flexi Diffuser behind the listening position (1-3 pieces), ensuring it covers the width of the workspace.

Once installed, you will immediately notice an improvement in airiness and spaciousness, as the diffuser absorbs stronger reflections, standing waves, and rattling echoes. This makes it especially useful in environments where high-quality sound is crucial, such as listening rooms, advanced home hi-fi or video rooms, and studios. These areas benefit from the elimination of close reflection points that can otherwise cause sound distortion and interfere with clarity.

The Flexi Acoustic Diffuser can enhance the sense of spaciousness and airiness in small rooms by diffusing the sound energy throughout the space.

Science and Operation:

• Too Noisy and Over-Dampened Rooms

• Diffusing – Spreading and diffusing high-frequency energy

• Absorption – Regulating and absorbing sound and resonance

• Combined Approach – Control of directed frequencies

The concept behind the Flexi Diffuser provides an affordable way to control high-frequency energy. High-end diffusers can be extremely expensive, costing up to 1000 EUR, and are usually found only in high-end rooms. By combining a simple diffuser with a sound-absorbing panel, the Flexi Diffuser delivers excellent performance at a more accessible price. On the next page, you can see how this is achieved.

Live-End, Dead-End Room Designs

The question is simple: why diffuse energy at all? Why not just absorb the entire audio spectrum? Let’s go back to the early days of recording (around 1960), when many studios were treated solely with sound-absorbing materials, resulting in flat and dull rooms. Engineers soon realized that listening in an artificial, overly dampened environment resulted in recordings that didn’t represent real-world acoustics.

Around the 1970s, a new studio design concept emerged. This approach treated half of the room with absorption panels (the “dead end”), while the other half remained untreated (the “live end”). This “dead-end with live-end” design allowed sound engineers to make critical decisions, such as special positioning, while eliminating echoes and enabling the sound to express its real energy at the other end of the room. Although the sound improved, problems persisted.

In the 1980s, diffusers began to spread and find their place in studios to eliminate rattling echoes and issues caused by strong primary reflections. Over time, this concept evolved, and today, in most rooms, the amount of sound absorption is higher at the source end of the room, while the receptive end remains relatively lively, aided by both natural and artificial diffusers.

Flexi Acoustic Diffuser:

Diffusion – High-Frequency Energy

There are many types of diffusers with varying designs, but they all share some common features. They have irregular patterns designed to break down and diffuse sound energy in different parts of the room. Some diffusers, like the razor blade design, are specifically engineered to break down each frequency evenly through a phase trap. These are highly effective but also expensive. On the other hand, products like the grid diffuser use a grating structure to randomly allocate sound arriving at various angles. While they are easier to build and less effective, they are much more affordable.

The Flexi Diffuser uses adjustable lamellas (slats) with variable inclination angles, which can be rotated to direct sound away from the listening position. This increases the sense of spaciousness and airiness in the room. This innovative design optimizes sound scattering and adjusts the direction of reflections based on the seating position, offering an ideal solution for balancing sound diffusion.

Sound Absorption and Diffusion: Checking Sound Energy and Resonance

What sets the Flexi Acoustic Diffuser apart is that it combines both sound diffusion and sound absorption. You can think of it like a two-way speaker, where the high frequencies are diffused and the low frequencies are absorbed. The low frequencies dissipate among the adjustable lamellas, while the sound-absorbing panel behind the lamellas absorbs the energy efficiently.

The built-in sound-absorbing panel is made of a specially developed 5 cm thick acoustic wool. This wool redirects low frequencies away from the lamellas, allowing them to spread out further—by up to half an octave—making it 80% more efficient below 250 Hz. The design ensures that any low frequency that bypasses the lamellas will be absorbed, and any sound that enters the sound trap behind the lamellas will be neutralized, preventing resonance.

Combined Approach: Control and Diversion of Directed Frequencies

As acoustic experts agree, sound waves below 200 Hz tend to radiate in a spherical shape. The primary role of an acoustic diffuser is to scatter energy while absorbing a portion of it (specific to the material used). High frequencies, which contain less energy than low frequencies, are much easier to control, which is why treatment of high frequencies above 1000 Hz is less challenging. The real difficulty lies with lower frequencies. To diffuse a frequency like 400 Hz, a diffuser needs to have a depth of at least 8 inches.

Without a high-density material, sound simply passes over. For example, a plastic bag doesn’t absorb sound, even though it contains air. This is why the Flexi Diffuser is made of high-density, heavy wood. When sound hits the lamellas, most of it is reflected back into the room, ensuring effective diffusion.

Details and Specifications:

The Flexi Diffuser is a combined acoustic diffuser and sound-absorbing panel that helps eliminate standing waves and rattling echoes without over-dampening the room.

Its innovative design includes six adjustable lamellas that can be rotated to direct sound energy away from the primary listening position. Behind the lamellas is a 5 cm thick acoustic wool panel with a 90 kg/m³ density. This panel absorbs lower frequencies while minimizing resonance, creating a more spacious sound. The combination of absorption and diffusion helps reduce reverberation, improving clarity in higher frequencies.

The external wooden frame is made of hardwood and comes in five different colors, and the Flexi Diffuser is delivered fully assembled, avoiding the hassle of home assembly.

How to Use:

The Flexi Diffuser is delivered fully assembled in a dedicated box. It typically takes only about 5 minutes to mount it on the wall using the provided hooks.

You can place the diffuser anywhere in the room to efficiently dissipate sound energy. Thanks to its robust size, it does not need to be fixed or drilled; it stays in place even when placed on the ground.

Ways of Placement

The ideal positioning depends on the room layout and desired sound effects. The main advantage of the Flexi Diffuser is its adjustability. It can create either a duller, more absorbing environment or a livelier, more dynamic sound from a previously dull space.

The Flexi Acoustic Diffuser typically features six or more inlet ports (depending on the size) to protect the width of the listening area or workspace. You can stack the panels to cover an entire wall, better controlling the balance between sound diffusion and sound absorption.

FAQ:

Application – Rear Wall Positioning

Acoustic diffusers are typically placed at the rear of the room, where direct sounds from the monitor loudspeakers can create strong reflections and phase delays. To achieve the best results, most designers position several Flexi Diffusers across the workspace behind the listening position. These diffusers are usually positioned at ear level or slightly higher to maximize the “width” of the listening space. Therefore, the center of the diffusers should always be at ear level when seated.

 

Application – Corner Positioning

In smaller rooms, the Flexi Diffuser can enhance the sense of spaciousness and airiness by effectively diffusing sound energy. The lamellas with variable directions allow for the removal of sound energy from the primary listening position, while utilizing the room’s natural boundaries to diffuse high-frequency energy.

Additionally, the inner acoustic panel aids in absorbing low frequencies—a common issue in small rooms. This combination of diffusion and absorption ensures that sound is evenly distributed throughout the space, creating a more balanced and clearer audio experience.

Application – Varying acoustics

The optimization of the acoustics of a room with measuring instruments alone does not always make it possible to be ideal for a listener. The acoustic musical instruments such as the violin, cello, acoustic guitar, and piano demand a livelier space while the electronic guitars and drums output more energy. Therefore, sometimes different room absorption must be set. The Flexi Acoustic Diffuser makes the change of studio acoustics simple as it simply rotates the wooden lamellas of the acoustic diffuser in the opposite direction compared to the sound reflections.

How Do I Set the Exact Direction of the Lamellas?

The simplest method is to sit in the listening position and listen to reference music while a friend slowly rotates the lamellas. Adjust the angles until the sound becomes clearer and more open. Typically, this happens when the sound is directed away from where you are sitting. Once you’ve found the desired position, mark the angle of the lamellas with a pencil or marker to remember it.

Is There a Specific Angle That Functions Best?

Not really. However, the worst position is when the lamellas are set perpendicular to the sound source, as this causes the sound to reflect directly off the hard surface. Using imaginary vectors or a mirror can often help you determine the ideal positioning within the room.

Is It as Good as Other Products?

Yes and no. Keep in mind that no room is acoustically perfect, and the human brain and ears are very effective at compensating for the room’s anomalies. Once you find the ideal setting, you’ll begin to understand how the room responds to sound, and this will help you optimize the acoustics for the best possible listening experience.

In a studio, can it be hung on the wall?

Can It Be Used in Other Ways?

Yes, of course, why not? While we did not specifically design it for such use, its structure easily supports it. It is heavy, so if you decide to use it in this way, you must ensure it is securely placed.

Can It Be Used Instead of the Side Acoustic Absorber?

Yes, absolutely. If you have a particularly sophisticated audio room (with many reflections) and want to add additional acoustic treatment, the Flexi Acoustic Diffuser would be a great choice. It helps maintain the room’s airiness while effectively absorbing sound even at frequencies as low as 40 Hz.

I Noticed We Rarely Talk About the Problems of High Frequencies. Why?

We can control high frequencies much easier than low frequencies. That is why we usually talk about the high volume of low frequencies in a room. Besides diffusion, every acoustic panel handles the control of high frequencies therefore we usually do not mention it.

Can it be used instead of a bass trap?

It depends on what is the problem with the bass. The Flexi Diffuser absorbs the bass efficiently from 40Hz but it will not be as efficient as a bass trap. If we experience a too big reverberation we should combine it with the corner units or our bass trap.

Can I mount the on the wall in a way that there is a small gap between the wall and the diffuser?

Yes. There are no exact rules in acoustics. Generally speaking, the closer it is to the surface of the wall the fewer low frequencies it will be able to absorb. As it moves further from the wall it will be able to absorb more low frequencies while the sound diffusion increases. Thus, it operates as a magnifying glass.

Where to put it in a home theater?

The best place would be probably in the “reflection point” or on the walls where the strong direct sounds are the most noticeable. So, if you have a loudspeaker that is close to a certain wall and the wall causes reflection you should use the Flexi Diffuser there.

What is a natural diffuser?

There may be many kinds of natural diffusers such as bookshelves or rooms with odd lengths and widths. They are hard surfaces that may turn over and diffuse the sound energy that is hitting them.

Is it a good idea to place the absorbers among the diffusers?

Yes, why not? Remember that there are no rules cast in stone in acoustic treatment. If we create a relatively neutral working environment that allows us to enjoy our records in other rooms as well. Some people enjoy the record in a relatively untreated room while others prefer the sounding of a duller and calmer or a more intensively treated room. The perfect setting of a room usually requires several months of work and you will hear only thereafter how it will function. This is normal for every room but after that, most engineers like to work always in the same room.

Our diffusers are made from real wood. Due to the natural properties and structure of the wood (such as knots, lumps, and staining caused by leaking resin), the staining or painting may not be uniform, and the shades may vary across the surface of the diffuser. Therefore, we cannot accept complaints regarding these natural variations.

(The beauty and style of natural wood lie in its unique veining and structure, which results in special colors and shades during the staining or painting process.)