Apos Caspian Open-Back Headphone


Formal on the outside, fun on the inside

Made with hand-assembled, sustainable materials, the Apos Caspian is an open-back headphone that looks timeless and sounds thrilling. 

The sound 

We designed the Caspian to make you smile--not to be used as a microscope for analyzing every last detail. The bass is playful yet controlled, alive and extended with visceral rumble. The midrange is compelling, with a focus on realism and immersion. For the high-end, we wanted all the airiness and sparkle of a quality treble experience--without the fatigue. To get there, we introduced a series of dips between 2K and 7kHz that protect sensitive parts of your hearing from fatigue.

Explore the Caspian’s story, measurements, and creation process

50mm Kennerton dynamic driver: a tamed beast

Capable of producing a vast range of bass frequencies with minimal power requirements, the 50mm driver is a real beast. But beasts have to be tamed or else, in this case, they bleed all of that bass energy into the mid-range, creating a muddled, awful experience. 

We started with an extremely low-mass driver. Low-mass drivers respond quickly to signals and minimize decay time, resulting in a realistic sound. Then we mechanically decoupled the driver from the wooden housing, which decreased the total harmonic distortion. After that, we added a lightweight graphene layer to the diaphragm to boost rigidity, decrease distortion, and improve speed and decay. Finally, our engineers tuned the driver for an enveloping full-spectrum experience. 

Mini-XLR connectors: balanced, secure

The Caspian uses 4-pin mini-XLR connectors. We chose these because they’re the most secure connection: a headphone cable won’t detach unless you thumb the release. They also have the largest surface connection area, which plays a role in conductivity. 

Easy to drive

We created the Caspian so that you can drive it without an amplifier. At 115dB per 1mW power, it plays from most phones and laptops. 

Hand-stitched sheepskin ear pads 

We started with an inch-deep pad of acoustic memory foam and wrapped it in soft hand-stitched sheepskin leather. The look is plush, elegant, and luxurious, like the upholstery of a high-end sports car. We made them oval-shaped to accommodate a variety of ear shapes and sizes. 

The combination of deep memory foam and sheepskin leather creates a comfortable seal around the ears, with an emphasis on isolation and comfort. The materials also boost the low-end of anything you’re listening to, adding body and weight.

Handmade oak ear cups

The ear cups are made of all-natural oak sourced from the foothills of the Caucasus mountains. This is an non-endangered variety of wood that has excellent acoustic properties and doesn’t crack easily. 

Symmetry between ear cups is all-important when it comes to acoustical and visual balance, so we hand-milled each set of cups symmetrically from a single piece of wood rather than hand-match them after the fact. 

Headband: cuddly on the outside, steel on the inside

We worked with the factory that produces Beyerdynamic's headbands to create a lightweight yet resilient one of our own. We started with anodized black stainless steel and wrapped it in foam and hand-stitched leather. The result feels plush yet durable. It has a subtle amount of clamp force, but it and the headband’s size can be adjusted for comfort. 

Aluminum alloy grille  

We made the grilles as wide as possible to accommodate the large 50mm dynamic drivers. The Apos “A” is the headphone’s only branding. The cloth within is acoustically transparent, keeping out the dust without blocking the air or coloring the sound. 

Product highlights

  • Fun-sounding, non-fatiguing for marathon sessions
  • 50mm dynamic driver
  • Open-back
  • All-natural oak earcups sourced from the North Caucasus mountains
  • Inch-deep sheepskin ear pads with acoustic memory-foam inner filling.
  • Stainless steel yoke and headband
  • Natural leather headband for all-day comfort 
  • Aluminum alloy grille
  • Graphene-coated multilayered composite membrane with variable thickness
  • CCAW coil (aluminum core coated with oxygen-free copper)
  • Internal litz wiring


  • Driver: Graphene-coated multilayered composite
  • Driver unit: 50mm
  • Frequency response: 5-45,000Hz
  • Sensitivity: 115dB
  • Impedance: 33Ω
  • Maximum input power: 500mW
  • Ear cup outer material: Natural sheepskin leather
  • Ear cup inner material: Acoustic memory foam
  • Thickness of pads: 1” (27mm)
  • External dimensions of pads: 4.5” x 3.4” (115mm x 88mm)
  • Height and width of ear pad opening: 3” x 1.7” (77mm x 45mm)
  • Grille material: aluminum alloy
  • Headband materials: stainless steel, natural leather outer lining, bio-leather inner lining, polyurethane foam insert
  • Yoke material: stainless steel
  • Weight: 13.3oz (378g) 

What’s included

  • Apos Caspian headphone
  • Leather carrying bag
  • Stock headphone cable (single-ended 6.35mm termination)

What pairs well 

Featured reviews

"My new daily drivers!" -SoundNews

"The imaging is really good...things have a very specific placement in the field." -Joshua Valour

"This thing is crazy-good. It sounds amazing, and I truly love it." -The Honest Audiophile

"Takes any music that fatigues you and softens it into enjoyment." -Dan's Audio Reviews

"Absolutely a headphone I'll be reaching for."  -Passion for Sound

"This open back headphone has really deep bass extension that goes all the way down to the sub-bass." -Ryan Ho

"A rocking headphone that focuses on the emotional experience." -Evshrug

Apos Promise

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