Focal Stellia Closed-Back Circum-Aural Audiophile Over-Ear HeadphonesACOUSTIC SOUND PURITY HI FI CLOSED BACK HEADPHONES This very high end circum aural headphones manufactured at Focal is equipped with a new generation of exclusive electrodynamic speaker drivers, capable of working at low acoustic load while offering an extremely extensive frequency response (5Hz 40kHz). Thanks to the many cutting edge technology which are integrated in its speaker drivers (the frameless 100% copper voice coil, M shaped pure Beryllium