Focal - Stellia Headphones

Focal’s reference closed-back, and the only closed headphone the company builds on a pure beryllium dome.

Stellia is the closed-back sibling to the open-back Utopia. The two share the pure beryllium ‘M’-dome platform, and Stellia is the only sealed headphone Focal makes with a beryllium diaphragm. It launched in 2019 and remains the company’s reference closed-back, sitting well above the aluminium/magnesium models in the closed range.

Beryllium is the reason for the specification. It is extraordinarily stiff for its density and carries sound through itself roughly three times faster than aluminium or titanium, which pushes the diaphragm’s first breakup mode far out of the audible band and underwrites the 5Hz – 40kHz response figure. It is also difficult to form into a thin dome and hazardous to machine, which is why Focal makes these drivers in-house in France and reserves them for two models. The voice coil is frameless copper — wound and bonded to itself with no bobbin, so there is less moving mass and one fewer interface between motor and diaphragm.

Sealing a driver creates its own problem: the trapped air behind the diaphragm becomes a spring the driver has to fight, and any energy not absorbed reflects back through the dome as colouration. Focal’s answer is in the earpad. Half its height diffuses sound through non-perforated full-grain leather; the other half absorbs the signal through an acoustic fabric into memory foam. A vent in the driver balances bass against midrange, a second vent at the back of the cup relieves the rear wave, EVA foam absorbs the highs behind the driver, and acoustic diffusers inside the cup break up standing waves while stiffening the cup itself.

At 35 Ω and 106dB it is the most efficient of Focal’s reference models — deliberately so, since the point of a closed flagship is that it works away from the listening room. It will play properly from a phone dongle or a portable DAC as well as from a desktop amplifier. Note that Focal publishes no numerical isolation figure, so treat any dB attenuation claim with suspicion.

Features

• Circumaural closed-back headphones, handcrafted in France
• 40mm pure Beryllium ‘M’-shaped dome full-range driver — the only closed Focal built on beryllium
• Frameless copper voice coil bonded directly to the dome
• 5Hz – 40kHz response, 0.1% THD at 100dB SPL
• 35 Ω and 106dB — the most efficient of Focal’s reference models, drivable from a portable source
• Earpads split 50/50 between diffusion through full-grain leather and absorption into memory foam
• Full-grain leather in cognac or mocha, solid aluminium yokes and earcups
• Both cables supplied: 1.2m unbalanced 3.5mm and 3m balanced 4-pin XLR, OFC 24 AWG
• Carrying case plus a separate accessory storage box for the cables

Specifications

• Type: Circumaural closed-back headphones
• Driver: 40mm (1.6″) pure Beryllium ‘M’-shaped dome, full-range
• Voice Coil: Frameless copper
• Impedance: 35 Ω
• Sensitivity: 106dB SPL / 1mW @ 1kHz
• THD: 0.1% @ 1kHz / 100dB SPL
• Frequency Response: 5Hz – 40kHz
• Weight: 435 g (0.96 lbs)
• Finishes: Full-grain leather in Cognac or Mocha
• Supplied Cables: 1 x 1.2m (4 ft) OFC 24 AWG cable with 1/8″ (3.5mm) TRS jack; 1 x 3m (10 ft) OFC 24 AWG cable with 4-pin XLR
• Supplied Adapter: One jack adapter, 1/8″ (3.5mm) female to 1/4″ (6.35mm) male
• Carrying Case: 250 x 240 x 120 mm (9.8″ x 9.4″ x 4.7″), plus a separate accessory storage box
• Origin: Handcrafted in France, beryllium drivers made in Focal’s own workshops
• Note: Focal publishes no passive isolation figure in dB, and no power handling or physical headphone dimensions