Note: This product is made-to-order and ships within one week.

Sierra Aluminum solid aluminum open-back headphones

The Sierra Aluminum is an evolution of the Sierra Reference, built to mark five years of the Auribus project. It pairs a warmer, more controlled tuning with single-piece aluminum construction and a lightweight 400g frame. A 50mm dynamic driver, angled 3D baffle, and open acoustic design work together to deliver wide staging, natural timbre, and full-range extension.

Solid aluminum construction with SLM finish

The outer shell is formed using selective laser melting, a 3D metal printing process that produces a dense, durable aluminum structure. Each housing is hand ground and tumble polished, leaving a subtle raw texture unique to every unit. Beneath it sits a one-piece 3D printed enclosure that keeps resonance controlled while maintaining low weight for long listening sessions.

3D baffle for spatial accuracy

The internal geometry places the driver at an angle relative to the ear, helping sound arrive more naturally. An asymmetrical aperture shapes how air and sound move through the chamber, widening the perceived stage without losing positional accuracy. This design supports layered recordings, making placement and depth easier to follow.

50mm dynamic driver with paper cone

The Peerless paper cone driver emphasizes natural tone across the spectrum. Paper diaphragms are known for balanced stiffness and damping, which helps avoid harshness while preserving detail. Combined with the open acoustic structure, the result is a presentation that stays coherent from low bass through upper treble.

Linear extension system for full-range response

An updated version of the Linear Extension System manages airflow and damping to maintain consistent output across frequencies. The design supports extension from 20Hz to 20kHz, allowing both low-end weight and high-frequency detail to come through without abrupt roll-off. This is especially noticeable in recordings with wide dynamic range.

Adjustable comfort for long sessions

The frame allows adjustment of clamp force to suit different head shapes. At 0.88 lb (400g), the weight stays manageable for extended use. Dekoni hybrid leather and velour pads distribute pressure evenly while maintaining a stable seal. The floating headband design spreads load across the top of the head, reducing fatigue over time.

Amplifier pairing for optimal performance

With a 20-ohm impedance at 1kHz and moderate power demands, the Sierra Aluminum benefits from a dedicated amplifier. A unit capable of at least 280mW at 32 ohms with low output impedance helps maintain control over the driver and ensures consistent tonal balance at different listening levels.

Product highlights

• Open-back over-ear headphone design
  
• 50mm dynamic driver with paper cone diaphragm
  
• Solid aluminum SLM-printed housings
  
• Angled 3D baffle with asymmetrical aperture
  
• 20Hz–20kHz frequency extension via Linear Extension System
  
• Adjustable clamp force with floating headband
  
• Hybrid leather and velour ear pads by Dekoni
  
• Recommended use with dedicated amplifier

Specs

• Driver type: 50mm dynamic driver
  
• Impedance: 20 ohm at 1kHz
  
• Frequency range: 20Hz–20kHz
  
• Weight: 0.88 lb (400g) without cable
  
• Materials: aluminum, nylon, PETG
  
• Cable: 1.4 meter (4.6 ft) 3.5mm to 3.5mm cable
  
• Recommended amplifier power: 280mW @ 32 ohm with <1 ohm output impedance

What’s included

• Padded carry case
  
• 1.4 meter (4.6 ft) dual 3.5mm cable with 3.5mm or 4.4mm termination
  
• Dekoni Elite hybrid leather and velour ear pads
  
• Stereo wired headphones