But why beryllium? To represent sound waves more accurately, a dynamic driver or transducer’s diaphragm requires the right balance between weight, stiffness, and rigidity. These properties allow the driver’s diaphragm to vibrate back and forth like a piston, which produces the sound waves we hear. If the material of the diaphragm is not stiff enough, the diaphragm will be too flexible, and this flexibility will distort the sound waves it’s responsible for producing.
On the other hand, the diaphragm should be light enough to vibrate rapidly. It’s difficult getting a heavy diaphragm to move back and forth fast enough to produce the frequencies accurately as they normally would naturally in the real world. So, the ideal material is one that’s extremely light, but also exceptionally rigid.
Unfortunately, most metals become increasingly flexible, and less rigid, the lighter and thinner the material is worked during the manufacturing process. This is what makes beryllium and Focal’s manufacturing process so incredibly special. Beryllium has one of the highest strength-to-weight ratios of all known materials. Being such a strong metal, beryllium is an extremely difficult and expensive material to work with. However, Focal’s manufacturing facilities in France have mastered the process.
So, what’s the sound signature and physical result gained when the most rigid and lightest metal on the periodic table of elements is used in a headphone’s dynamic transducer? The most articulate, resolute, and highly detailed sound waves available in a dynamic driver, that’s what. Both you and your music will enter a new sonic dimension of high fidelity sound that's more similar to the resolute detail found in planar magnetic drivers. However, your music will retain that classic loudspeaker-esque low-end energy for which dynamic transducers are simply the best.