The Flax sandwich cone

Learn more about the Flax membrane

Flax is linen. Made in France yet affordable in price, Flax membranes are focused on acoustic performance, high-tech and bring a truly original design to the brand's loudspeakers!

After more than five years of research and development, in 2013 Focal engineers unveiled a new Flax membrane made from flax fibre. It's characterized by a very natural, uncolored sound, rich reproduction in the midrange and clean attacks in the bass.


The "F" membrane is a sandwich made from a core of high-quality flax fiber, embedded in two thin sheets of glass fibre. It meets all the criteria of a high-fidelity membrane: it's light to deliver good dynamics, rigid to hold the bass, and damping to deliver a neutral, natural listening experience.


A "single-material" cone can't perfectly meet all these criteria. Sandwich technology plays a very important role in the sonic neutrality of a membrane, a neutrality that has always been the signature of the Focal sound. Our mastery of sandwich technology on the Utopia and K2 Power ranges has enabled us to develop revolutionary "Flax" membranes that reconcile all 3 criteria.


Flax fibre is twice as light as glass fibre, because it is a hollow fibre. It has very low elasticity, making it ideal for increasing the flexural modulus of a sandwich structure. What's more, it can be obtained as a non-woven connector with a large diameter, providing the thickness and rigidity required for a sandwich.


Composite materials are the right choice for applications where stiffness and low mass are required. However, they are penalized by a lack of damping, leading to very poor vibration control. Recent developments combining composites and natural fibres offer unexpected opportunities. Flax fibre offers excellent internal damping on a par with glass fibre, Kevlar® or aluminium.


Flax membranes are designed and manufactured in France, using French flax fibre. France is Europe's leading producer of fibre flax, mainly in Flanders, Picardy, Normandy and Pas-de-Calais. French flax fibre is considered the best in the world.

Synthetic fibres or foams derived from petrochemical resources are subject to fluctuations in crude oil prices. Organic textiles or "ecotextiles", like linen, are competitive...

What's more, since the superlative "W" and "K2" sandwiches can only be made by hand, they can only be produced in limited numbers, for reasons of cost. The industrial process developed to produce the "F" sandwich makes this technology highly competitive.

Focal products using this technology


Subscribe to our newsletter and receive a preview of the latest audio innovations from Focal and Naim.