• -15%
Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
  • Acoustic Diffuser MDD-400-16 up to 45% off
Acoustic Diffuser MDD-400-16 up to 45% off

Acoustic Diffuser MDD-400-16

à partir de
55.00 € per pair
instead of 100.00 €

equivalent to a cost price of 27.50 € per diffuser

Pair of acoustic diffusers consisting of one type A diffuser and its inverse type B. These two types are mutually mirrored with respect to each other, in order to avoid problematic phase correlations that occur when two identical elements are placed in proximity.

Each diffuser is composed of 20 pre-cut lines, to be assembled by placing them next to each other.

Discount on quantity
Number of pairs
Percentage discount
Pair price
85.00 €
75.00 €
65.00 €
55.00 €
Diffuser price
42.50 €
37.50 €
32.50 €
27.50 €
You save
15.00 €
50.00 €
105.00 €
270.00 €
Number of desired pairs

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Andy Mac Door - The Best Diffuser at an Unbeatable Made in France Price

Three years of research were necessary to develop this revolutionary diffuser in terms of its efficiency and price. Nothing was left to chance in its design. Comprised of 400 "pseudo cells" on a stick in just 60cm², this French-designed and manufactured diffuser offers remarkable diffusion and dispersion properties, making it an essential reference.

Inspired by the QRD (quadratic residues) model, the PRD (primitive root) model, and the improved models LSD (Lüke sequence) and PWRD (power residue), the MDD (Mac Door Diffuser) sequence brings together the best of the most renowned sequences based on prime numbers to merge into a new formula patented in 2019, designed and optimized for stick diffuser designs.

This revolutionary sequence has the following characteristics:

  • DISTRIBUTING a different height per stick to spread the energy decay of the reflected wave as linearly as possible. This MDD model, composed of 400 sticks distributed in 20 columns and 20 rows, has 400 different heights.

  • REDUCING to the maximum negative phase correlations that produce irregularities in scattering, diffusion, and absorption by using a prime number per stick (patented formula by Andy Mac Door).

  • FAVORING the creation of real wells through the alternation of large and small sticks to approach the behavior of the theoretical model with cells created by walls, which is impossible in such a format. This further favors the accumulation of energy in the wells and optimizes energy decay.

  • DIVIDING the source wave into a large number of energy lobes over a wide frequency range by homogenizing phase correlations.

  • DISPERSING energy lobes symmetrically in a semi-spherical plane to preserve the spatial image of the room when the diffusers are positioned in a room dedicated to mixing or high-fidelity listening.

  • DISCARDING the need for 2D sequences based on prime numbers to use a different number of columns and rows (N-1) without compromising any acoustic properties.

  • AVOIDING resonances that can occur at certain frequencies (usually high) when diffusers are placed side by side and the energy lobes of neighboring cells correlate constructively.

Technical specification

Type of diffusion
Two-dimensional in half-sphere
Acoustic diffusion range
278 Hz - 14 768 Hz
Maximum cell depth
160 mm
Cell width
29.75 mm (on average)
Number of rod cells
None, each cell has its own height
Base height for assembly
17 mm
Raw material color
High-density extruded polystyrene
Fire reaction
Euroclass E
Weight of a diffuser
1,3 kg
Diffuser Dimensions (Width x Length x Height)
595 mm x 595 mm x 177 mm

The principle of diffusers is to break up a wave into multiple energy lobes propagating in all directions at regular intervals in time. The practical goal of this is to transform a specular wave into a diffuse field, thereby creating a homogeneous reverberation while preserving the tonal characteristics of the audio source and infusing it with "liveliness." In contrast to absorbent panels, which simply absorb the wave as much as possible before reflecting it, thus attenuating tonal changes due to reflections but "killing" the sound.

In practice:

- A room fully furnished with diffusers in addition to bass traps is ideal for music listening and work comfort. You are immersed in sound, the room feels alive, and it adds presence to the audio source without altering its tone. From a psychoacoustic perspective, our brain perceives the room as larger than it actually is, creating a sense of expansion.

- A completely absorptive room is ideal for recording and measurements. The listening experience is extremely faithful to the source, the room is inert (dead), and only the audio source is perceptible. From a psychoacoustic perspective, our brain no longer perceives the room and struggles to define its geometry, which can result in a sense of imbalance, or even nausea and dizziness for some individuals.

So, the ideal for the listener lies somewhere between these two extremes, depending on their use. A musician may prefer a highly diffusive room, providing substance to their instruments without much effort, as opposed to a recording engineer who generally prefers the musician to perform in an inert room to achieve the most faithful capture possible, which can later add the desired reverb using equipment or plugins.

An audiophile may share the musician's preference for stereo music listening but opt for a more absorptive room for surround sound listening, as the absence of room reverb is typically compensated for by the reverb in multichannel audio mixing. Cinema installations will be even more absorptive to replace the natural room reverb with that of the audio mix, providing a total immersion in the film's universe but potentially being less comfortable once the film is over.

The answer, therefore, depends on your preferences and your willingness to dedicate space for this purpose. In both cases, the ideal acoustic treatment involves replacing all smooth and reflective surfaces with absorbing or diffusing materials. The most versatile solution is to alternate between absorption and diffusion, creating a checkerboard pattern on all surfaces. The amount of material needed will often depend on the compromise you are willing to accept.


The extruded polystyrene used in the manufacturing of the diffuser displays an off-white hue with a tendency towards light beige. Due to the nature of the material, its color undergoes significant variations depending on the type of lighting. Standard warm lighting, common in most households, accentuates the beige tone, while in natural light, white predominates. The raw color of your diffuser will greatly depend on the type of lighting you use. The image above illustrates the difference in hue observed on the diffuser based on the lighting.

The main difference between wood and extruded polystyrene as a choice of construction material for an acoustic diffuser is obviously the mass of the material. Spruce wood is approximately 15 times denser than extruded polystyrene, making it more capable of reflecting lower-frequency sounds. For higher frequencies, extruded polystyrene reflects sound waves just as effectively as wood.

So the question is, at what frequency does polystyrene begin to reflect waves less effectively than spruce wood?

The answer is around 500 Hz to start observing a decrease in the reflection coefficient, becoming more pronounced around 250 Hz. In conclusion, wood is superior to polystyrene for diffusing waves below 500 Hz - 250 Hz. However, this also depends on the dimensions of the diffuser. For that, the cells would need to be greater than about 15 cm - 20 cm deep.

For this reason, the MDD-400-16 diffuser does not have wells exceeding 16 cm in depth. Beyond this depth, extruded polystyrene would not be dense enough to effectively reflect lower-frequency sound waves. It can, therefore, be concluded that wood becomes essential only when the diffuser has a depth of more than 20 cm in order to diffuse lower-frequency sound waves.

The MDD-400-16, with cells less than 16 centimeters deep, offers nearly equivalent performance compared to a wooden diffuser of the same design.


By choosing MONDIAL RELAY as your carrier, you have the option to ship your products at the best price to a pickup point available in FRANCE, BELGIUM, LUXEMBOURG, THE NETHERLANDS, SPAIN, AND PORTUGAL, or have them delivered directly to your home in GERMANY, BELGIUM, LUXEMBOURG, THE NETHERLANDS, SPAIN, PORTUGAL, AUSTRIA, AND ITALY.

By choosing LA POSTE as your carrier, you have the option to ship your products directly to your home, whether you're in OVERSEAS or anywhere in EUROPE (inside or outside the European Union).

The MDD-400-16 acoustic diffusers are directly produced by Andy Mac Door and shipped from France. Therefore, if the destination country is located outside of the European Union, customs fees may be imposed by the customs services of the destination country. Hence, if the destination country is outside of the European Union, we encourage you to find out about customs requirements on your own.

Delivery times correspond to the number of business days (Monday, Tuesday, Wednesday, Thursday, Friday) required for the preparation and shipment of your order. Additionally, since the MDD-400-16 acoustic diffusers are designed directly by Andy Mac Door, production times need to be added to the shipping times.

Production Times:

  • 2 to 5 business days per set of 36 diffusers.

Shipping Times:

  • By MONDIAL RELAY to a pickup point -> 3 to 6 business days for France, Spain, Portugal, Germany, Belgium, the Netherlands, and Italy (generally observed times).
  • By LA POSTE to your home -> 3 to 6 business days for France, 1 to 2 weeks for countries in the European Union, and 2 weeks to 1 month for overseas territories and countries outside the European Union (generally observed times).


The MDD-400-16 acoustic diffusers are packed in pairs in a box measuring 60*40*30cm to comply with standard carrier dimensions. Each pair consists of one type A diffuser and its inverse type B diffuser. This means that the type A diffuser is nested inside the type B diffuser in their box. Each line of rods composing the diffuser is numbered from 1 to 20, preceded by the A or B designation to differentiate the type of diffuser and to make assembly easier after unpacking.

As a result, each pair of diffusers is shipped to you in a package with its own tracking number. Therefore, if you order 12 sets of MDD-400-16 acoustic diffusers, you will receive 6 tracking numbers, each tracking independently of the 6 packages.

When your order exceeds 18 diffusers, the shipment is divided into multiple parts to avoid overloading the pickup point that receives your packages. This means that when you order 24 diffusers, you will receive 6 packages initially, and then another 6 packages 2 to 3 business days later.