Ollo Audio X1

According to the manufacturer, each Ollo Audio X1’s frequency curve is hand-linearised. The result is an open-back headphone with a high-quality material mix and a wide frequency range, whose sound ties in with the warm character of other Ollo Audio models but has a more open treble presentation. How it fares in detail – including its “neutral” sonic qualities – and how the included audio plugin performs, is covered in this review.

Solid package contents

Handmade in Slovenia, the Ollo Audio X1 comes with an unsymmetrical detachable cable with a mini-jack plug, connected to both ear cups. It is mostly black, with the cable ends after the Y-split in signal red. A screw-on adapter for a full-size jack is included, along with a registration card and serial number, needed to download the calibration software. For its price class, the package is “solid.”

Selected materials

The headband is made from stainless steel, making it robust and durable. A silicone insert appears to dampen the structure-borne sound of the metal frame. The ear cups are CNC-machined from a single piece of American walnut and can rotate freely 360 degrees. The rear is covered by black lacquered metal plates with large openings.

The contact surface of the large ear pads is made from soft velour, surrounded by a perforated synthetic leather ring designed to further support the open sound character. Thanks to accessible screws, the headphone can be easily serviced after the five-year warranty, including replacing the headband, ear pads, or ear cups.

Wide frequency range

The dynamic drivers inside the X1 are slightly angled within the ear cups to improve sonic performance. They offer playback down to 5 Hz in the bass and up to 22 kHz in the highs, exceeding the typical human hearing range on both ends.

The measured average impedance of 32.85 ohms makes it compatible with a variety of headphone amplifiers, including low-voltage outputs from some audio interfaces, laptops, and smartphones. Comparing the X1’s frequency chart with other headphones shows it has a noticeably flatter response.

Handling the Ollo Audio X1

The detachable cable connects to both ear cups and locks securely so the plugs won’t slip out under light tension. The 2-metre length provides good studio mobility. There’s no printed left/right marking, but if the cables are routed forward, the slightly offset connectors indicate orientation.

The headband adjusts automatically, while its arc remains constant. Despite its size, the headphone’s weight of 397 g without cable is relatively light. The clamping force is strong enough to keep it stable during head movement, and the combination of memory foam and velour pads ensures comfort even in long sessions.

Software for the Ollo Audio X1

Using dSoniq’s USC II software (from the Realphones suite), the X1’s playback can be linearised. This is done via EQ in the software rather than in the headphone itself. After registering the X1 online, the software can be downloaded for free, available as both standalone and VST plugin versions.

A calibration file specific to the X1 must first be downloaded from Ollo Audio’s website. When using the software, a virtual sound card is created, and the calibration file is loaded. From there, playback on the computer is tailored to the X1, with adjustment from 0% to 100% possible – also for the plugin version.

Sound of the Ollo Audio X1

The X1’s sonic character is in line with other Ollo Audio models we’ve tested: fundamentally warm, with bass extension down to 5 Hz, capable of reproducing sub-bass in urban music, though with less definition than ideal. Bass is present but slightly blurred, lacking the punch of some competitors.

The midrange is also warm, offering excellent speech intelligibility, and blends smoothly into the silky, understated highs. This contributes to pleasing subjective detail resolution. With treble extension up to 22 kHz, the headphone delivers a spacious high end. Dynamics are on the softer side, but distortion-free even at surprisingly high gain levels.

More sonic flexibility via software plugin

Without the plugin, the X1’s frequency response is balanced; calibration offers a different, but not necessarily “better,” sound. Users should keep in mind that strict neutrality may not match consumer listening habits, though it is useful in production. The USC II plugin also simulates different listening environments, from FOH mixes to studio and car sound.

It can also adapt the headphone’s tuning for binaural mixing or to the popular Harman curve. Whether this is helpful for mixing depends on the user’s workflow and other translation-checking tools.

Conclusion

The Ollo Audio X1 is an open-back over-ear headphone that impresses with its material quality, high comfort, and understated design. It delivers on its promise of balanced sound, offering a warm tonal balance with more open highs than other Ollo models and ample bass reserves – though with less definition than its mids and highs. Its frequency response can be individually calibrated via the included plugin, making it suitable for all production stages from editing and mixing to mastering. Its sound quality also makes it appealing for HiFi enthusiasts.