We’re taking you through the process of designing the unique sound of our award winning headphones. With an intricate view on our bio-cellulose diaphragm in our S05 speaker units, we go through the key factors when designing sound, such as harmonic distortion.

The Bio-cellulose diaphragm

The bio-cellulose speaker diaphragm in S05 is made of a bacterial cellulose, which is an organic compound that is grown using certain types of bacteria. Bio-cellulose is a really interesting material for many reasons; it’s renewable, biodegradable and it has great acoustic properties. If you look closely at the diaphragm you may be able to see that it contains a structure of very fine fibres. These fibres construct a very stiff but lightweight material which makes it ideal for the use a speaker diaphragm. 

How it affects sound

The diaphragm of a theoretically perfect speaker will move like a piston. It moves back and forth without any rocking, tilting, wobbling or changing shape at all. In order to achieve that the diaphragm material must be as stiff as possible. If the diaphragm material is too flexible it will sympathetically resonate at frequencies that are harmonic to the frequency of the sound we are trying to reproduce. We want to avoid this resonating motion as it causes harmonic distortion. There are plenty of very stiff materials, but we also need to take the weight into consideration. A heavier diaphragm requires more power to move, so to play music at the same sound pressure level we would need a more powerful amplifier that consumers more battery power. Fortunately the bio-cellulose diaphragm is able to provide the stiffness we need without weighing more than the alternatives. 

Harmonic distortion

In short harmonic distortion is unwanted energy at the harmonics of the sound we are trying to reproduce. The harmonics of a sound is the whole number multiples of the frequencies contained in the sound wave. So if we are trying to play a pure sine tone with a frequency of 200Hz we may hear energy at 400Hz, 600Hz, 800Hz, and so on as well. When comparing speaker units we measure the Total Harmonic Distortion (THD), which is the root mean square of all the unwanted harmonic components in the measured sound. 

The S05 Driver is engineered with a 40mm speaker diaphragm made from stiff Bio-Cellulose for more defined high-frequency details, more pronounced mid-range, better dynamics, and more natural tonality.

The role it plays when listening to music

If music is played through a poorly designed headphones that produce a high amount of harmonic distortion, it will simply sound wrong and unnatural. This is because the harmonic distortion changes how we perceive the timbre and tonality of the sound, which is obviously really problematic when producing music or mixing a track. The biocellulose diaphragm on the other hand is able to reproduce the music faithfully with great clarity, even at high volume levels. 

About the S05

For the S05 we paired the biocellulose diaphragm with a high grade neodymium magnet, which resulted in a speaker unit that offers a clear mid-range, better dynamics and a more natural overall tonality. When tuning the speaker unit we paid special attention to the clarity in the mid-range, without compromising the extension in the bass range. This results in a very wide sound stage with great instrumental separation. The listener is able to extract and enjoy every little detail in the music.  



We asked Nikolaj from our audio engineering team for some final words on the bio-cellulose diaphragm.

"Bio-cellulose is not only great acoustically, it is also a more responsible material in terms of production and environmental impact. It is completely pure and toxin-free, which is why it is often used for medical applications such as prostheses. The bio-cellulose is even completely biodegradable. So we can create great sounding headphones without polluting the environment with toxic metals such as beryllium which you may find in some other high-end headphones."



TMA-2 HD variant (S05 H04 E04 C15)

With the E04 over-ear leather cushions for wide soundstage, high comfort and high isolation.

TMA-2 HD Wireless variant (S05 H05 E04 C15)

With the E04 over-ear leather cushions for wide soundstage, high comfort and high isolation.

TMA-2 HD variant (S05 H03 E02 C15)

With the H03 leather headband and E02 leather on-ear cushions for an all leather configuration.