The Auribus Acoustics Sierra Reference Headphones Review

From Southern California, a new headphone manufacturer has emerged. Auribus Acoustics is a company that has been making headphones for a few years now, and they have now made their way to Audio46. Two new pairs of cans have arrived at our doorstep, and I'm excited to review them and see what they're all about. The Sierra Reference headphone is a $1200 open-back experience that is meant to disrupt the high-end competition. How is the sound really? In this review, we'll be analyzing all the details and see if the Sierra Reference cans are worth being up against the classics. 

The Sierra Reference headphone is unlike anything I have seen for a headphone before. At first glance, I was nervous about how they would feel on the head. The design is bulky and clunky; it takes up space when you probably would prefer it to be smaller. The way the earcups rotate is awkward, fans outwards, and the axis for the earcups themselves makes the rotation quite cumbersome. The build is quite sturdy, almost industrial, and feels a bit stiff when you try to adjust the headband. Just holding the Sierra headphones in my hands, I was wary of the comfort: how comfortable was this stiff of a headphone really going to be? 

If there is anything I learned in my time as a headphone reviewer, it is that looks can be quite deceiving. The Sierra Reference headphone, in all its clunky glory, is actually quite comfortable and form-fitting on the head. Even with glasses on, I found no fatigue or discomfort from the way they sat on the head for the hours that I wore them. The clamping force was just tight enough to be stable on the head, but it didn't squeeze uncomfortably. It was impressive, and the rotation of the earcups allowed for an excellent seal of the ears for optimal immersion. 

The earpads, courtesy of Dekoni Audio, are velour and leather, making a perfect combo of plush and stability for your ears. I was happy to wear the Sierra Reference headphones for multiple hours, testing them with multiple DACs and amplifiers to find the best fit. I used the iFi Valkyrie and the Chord MOJO 2, and found that the greater power did aid in getting the most out of the Sierra. Traveling with the Sierra Reference may prove to be a bit difficult, since the headphones don't fold up or lie flat in a neat way. The Sierra does come with a very handy travel case, although it is on the larger side. 

• Weight: 340g Headphones (Without cable)
• Construction: Nylon, Aluminum, and PETG
• Driver: 50mm Paper Cone Dynamic Driver
• Impedance: 20 Ω at 1kHz

(Depending on volume preference, a 280mW @32 Ohm amplifier with <1 Ohm output load is recommended for an optimal experience.)

SOUNDSTAGE & IMAGING

Time for the real meat and potatoes of this review: the sound analysis. The Sierra Reference headphones really surprised me in the best way. I was immediately put into an immersive soundstage that wrapped sound around me. The presentation was very forward in the midrange, then having the bass and treble filter a bit behind to make the most melodic instruments most noticeable. I was definitely a fan of how dynamic the signature was, with punchy lows and airy highs, all while the midrange stayed focused and detailed. The signature itself was pretty flat, but I was impressed with the depth and height given to make the stage much more open. 

The soundstage of the Sierra is quite wide, both in horizontal space and vertical height. I was able to create an accurate image in front of me with a lot of space in the stereo sound field. It expanded pretty far vertically, allowing for distinct separation between elements. Even in the spots near the center where things could sound cluttered or too busy, you could hear how the Sierra layered the elements to expand backwards and even upwards to make sure everything got a chance to shine. This allowed for the soundstage to feel very open and lightweight as opposed to heavy and compressed. The Sierra was immersive, and while there was a lot of sound bleed, it was perfect for getting lost in the music.

BASS FREQUENCIES

Open-back headphones, I find, tend to have a more relaxed bass than some other headphones. It is easier for this section to be filtered out or lose its power because the space between the treble and midrange becomes more prominent. The Sierra Reference headphones strike a great balance of power, drive, and relaxation in the bass frequencies. This is a reference headphone before anything else, so it was nice to hear that the Sierra's bass wasn't overpowering or driving too much to become the only thing you hear in the sound signature. Instead, you heard a punchy bass that sat behind the midrange, staying present and colorful to support the main melodies of tracks. It laid a solid foundation for other frequencies to build up from. Instruments sounded natural and detailed, even expanding down into the sub-bass zone with grace. 

MIDRANGE FREQUENCIES

The midrange in the Sierra Reference was a favorite of mine. It can be hard to strike a good balance between colorful dynamics and natural reproduction, but the Sierra does it exceptionally well. The midrange highlights vocals as a forefront instrument, and everything else filters around it like a live band were playing in the same room. The timbres of instruments were natural and honest, coming in with full detail and texture to make them easily recognizable. The elements in busier tracks were able to flow together cohesively while still having distinct separation. The natural reproduction of all the instruments made this headphone earn the “reference” name in its title. I could see this being a good option for studio engineers looking for an open-back that has a bit more flair than a typical Sennheiser or Audio-Technica. 

TREBLE FREQUENCIES

The treble of the Sierra Reference headphones comes in to balance everything gracefully. It is bright and energetic, with a lot of life and color to match the punchiness of the bass and layering of the midrange. The Sierra has a very open treble range, where tracks can expand upwards in height and frequencies can disperse naturally. In the treble, you can hear how much space is given to instruments and a look into their recording environments. Long echoes and reverberations ring out to the very top of the soundstage, and they come with a subtle brightness and detail that only the treble can provide. The treble's bright detail and precision carry throughout the whole signature, allowing the sound of the Sierra to be lightweight and easy to listen to for long listening sessions. It matches the bass in clarity and color, so you get a clear picture of all the frequencies together. 

What headphones compete with the Auribus Acoustics Sierra Reference? There are a lot of reference headphones that come to mind in the $1200 range, especially those used for reference listening. The Audeze LCD-X is a classic for reference sound, as well as the Dan Clark Noire XO. The new Austrian Audio Arranger is a fine choice for dynamic reference sound, and the Focal Clear MG offers a lot of detail with its planar magnetic driver. So what makes the Sierra Reference stand out amongst these options? 

Comfort is something I find to be a winner in the Sierra. Albeit bulky, the subtle clamping force and overall lightweight feel are easy to wear for long periods of time. Headphones like the LCD-X and the Clear MG are on the heavier side, so you could get fatigued faster from just the physical quality alone. Dan Clark lies a bit more relaxed in sound signature, making the Sierra a much more forward option. The Arranger is a match in terms of sound, offering similar dynamic color and naturalness at a similar price point. 

The Auribus Acoustics Sierra Reference headphone should definitely be on people's radar. With its comfortable wear style and natural timbral detail, it is sure to become a classic for any audiophile looking for an upgrade in their setup. Audio engineers can appreciate the neutrality and natural detail, and even people who want a fun listening headphone can tune in to the colorful detail across the range. People who prefer analytical listening will adore the Sierra, as well as those who prefer something neutral and not too distracting. The build quality is deceptively comfortable, so you are sure to enjoy the headphones for hours without fatigue. 

You can get the Sierra Reference headphones at Audio46.