What is Metamaterial Absorption Technology?

Metamaterials are engineered materials with properties not found in nature, designed to control and manipulate energy, in this case, sound waves. In KEF speakers, MAT™ is a highly complex maze-like structure that eliminates unwanted sound from the rear of the driver, resulting in a purer, more natural performance.

Traditionally, when sound emanates from a tweeter, practically 50% of the sound waves bounce backwards, reflect off surfaces inside the speaker’s enclosure and exit through the bass port(s), causing distortion to the sound. This is where MAT™ comes in.

This technology uses a series of up to 30 intricate, maze-like channels, known as absorbers, each tuned to absorb a specific sound frequency. These channels work together to capture and dissipate 99% of the unwanted noise, allowing the listener to hear the purest sound, free from distortions.

For more information on how we integrate MAT™ into our speakers, visit our Metamaterial Absorption Technology Page.

As part of our ongoing mission to deliver crystal-clear, perfectly balanced sound, from treble to bass, and everything in between, our team of engineers took on the challenge to solve the problem of distortion / partial superimposition of waves caused by sound from the rear of the tweeter.

Firstly, we need to talk about the sound generated by a loudspeaker driver unit. Put simply, when the diaphragm of a drive unit vibrates, it generates sound. When a loudspeaker is in operation, an equal amount of sound energy comes from the front of the driver unit towards you - the listener, and from the back of the driver unit to the inside of the enclosure. If untreated, some of this sound energy is reflected to the diaphragm of the drive unit or leaves the speaker through the bass port(s) which causes distortion.

“We want to absorb the sound behind the drivers because we want to hear the music, not the artifacts created by the driver or the cabinet itself." - Dr Sébastien Degraeve, Senior R&D Engineer.

This has been a problem in speaker design for many years. In fact, up to now, most loudspeakers still rely on the use of porous materials, such as foam or wool, to dampen these internal reflections.

KEF was one of the pioneers in the use of this technique back in the mid-1960s. The drawback of this technique, however, is the inconsistency of the material (the material itself or the application) and the acoustic volume it is taking.

Another solution is to extend the enclosure to direct the sound energy away from the driver unit, but with this method, a very long enclosure is needed behind the drive unit to achieve a meaningful effect. The effect is also limited to certain wavelengths as this long enclosure is only one single channel while KEF is using up to 30 channels in the Meta disc to absorb unwanted frequencies.

The development of MAT™ was a collaboration between KEF engineers and the Acoustic Metamaterials Group (AMG). The core of this innovation lies in the absorber disk, integrated into the back of the Uni-Q driver array.

Each absorber consists of up to 30 maze-like tubes that are precisely tuned to absorb different frequencies. This design enables broadband absorption, covering a wide frequency range from 620Hz upwards. The sound waves that would typically reflect back into the speaker are absorbed, significantly reducing distortion.

It is true that if the tweeter is listened to on its own without the contribution of the bass/midrange driver - and here we are talking of frequencies above about 3kHz - very little seems to come out of it.

However, if you were to listen to any loudspeaker without the tweeter connected, you would certainly notice that the sound is muffled, it gets harder to distinguish the different instruments and voices, and the sense of space is lost. It is because our hearing relies on these high-frequency sounds to give us the detail. This detail comes from the tweeter and the better the tweeter, the more the enjoyment of listening to music, watching a film or becoming immersed in a video game.

Thanks to our MAT™ Technology, the overall sound is cleaner, especially at higher frequencies, and you hear a purer, more natural performance with almost no distortion.

For audiophiles, the benefits of Metamaterial Absorption Technology are transformative. MAT allows KEF speakers to deliver sound that is not only clearer but also more detailed. Listeners can experience everything from the subtlest notes in a string quartet to the powerful bass of a dance track with clarity and precision. The broadband absorption provided by MAT creates an expansive, immersive soundstage.

Whether you're a music lover, a home cinema enthusiast, or a professional audio engineer, KEF’s Metamaterial Absorption Technology enhances your listening experience, offering precision and clarity that were previously unattainable.

Now applied to many of our leading ranges, our award-winning MAT Technology features in BLADE Meta, The Reference Meta, R Meta HiFi Speakers, LS60 Wireless, the LS50 Collection, and most recently, the Q Meta models.