Grado Signature S550 open-back headphones boast big drivers and Brazilian Walnut housing

Brooklyn-based manufacturer Grado Labs has released a fourth addition to its acclaimed Signature headphone line. The Signature S550 arrives with an emphasis on musical warmth and long-session comfort, in distinctive Grado style.

At the heart of the new Signature S550 is a 50mm dynamic driver, known internally as the S2. Rather than introducing an entirely new driver architecture, Grado engineers have focused on optimising the relationship between the driver and the headphone’s enclosure.

The S2 unit is tuned specifically for the S550’s wooden housing, a pairing said to deliver a warmer, more forgiving sonic character while maintaining the immediacy and detail that have long defined the brand’s sound. The result, according to the company, is a presentation designed for extended listening sessions, with a wide soundstage, precise imaging and natural dynamic range.

The headphones operate using an open-air design, a configuration that allows air to move freely through the driver housing. This approach typically supports a spacious and natural presentation, with reduced internal resonance compared with sealed designs.

Key specifications include a 50mm dynamic driver, open-air operation, a frequency response of 6Hz to 44kHz, and a nominal impedance of 38 ohms. Total harmonic distortion is rated at less than 0.2 per cent at 100dB, with a sensitivity of 112dB. The headphones weigh 335g without the cable.

The headphones operate using an open-air design, a configuration that allows air to move freely through the driver housing…

Brazilian walnut construction

A defining feature of the S550 is its housing, crafted entirely from Brazilian walnut. Wood has long played a central role in Grado’s headphone design, valued not only for its distinctive appearance but also for its acoustic behaviour.

Each enclosure is individually produced, with natural variations in the wood grain ensuring that every pair has a slightly different visual identity. Walnut is chosen for its density and stability, qualities that contribute to the S550’s balanced tonal character while helping maintain consistent acoustic performance over time.

The company notes that the timber is sourced with sustainability in mind, supporting long-term availability while recognising the ecological environments from which it originates.

The Signature S550  introduces a detachable cable system as standard, reflecting a growing interest among enthusiasts in modular headphone setups.

Each earcup terminates in a 4-pin balanced mini XLR connection, allowing the use of Grado’s expanding range of alternative cables. The included Signature Silver cable is designed to be lighter and more flexible than earlier Grado leads, helping reduce cable noise and improve comfort during longer listening sessions.

At the source end, the cable terminates in a 3.5mm mini jack and includes a 6.3mm adapter, allowing the headphones to connect easily to a wide variety of audio equipment, from portable players and DACs to full-size Hi-Fi amplifiers.

The S550 ships with the company’s new B cushions but remains compatible with the full range of Grado ear pads, allowing listeners to adjust both comfort and tonal balance to their preferences.

The headphones also use the Signature Line headband assembly, which incorporates a flexible metal support inside a leather band.  

Other structural details include engraved metal gimbals, stainless-steel height rods and reinforced junction blocks. The earcups feature controlled rotation to maintain stability while accommodating different head shapes. The S550 also adopts the narrower leather headband strap first seen on the S750 model.

The Grado Signature S550 headphones are scheduled to ship later in March, priced at £995 ($995).