The Auribus Acoustics Sierra Aluminum Headphones Review

Everyone knows Hifiman, Audeze, and Sennheiser for their audiophile headphones. Brands like Meze Audio and Dan Clark also stand out, but what if we entered another new contender? We've reviewed Auribus Acoustics at Audio46 before, looking at their Sierra Reference headphone. They also have the Sierra Aluminum open-back headphone, which retails for $1600. This open-back headphone enters a crowded field of competition, so what makes it stand out? In this review, we take a look at all the details of this headphone that make it a stand-out in a stacked line-up. 

Having reviewed the Auribus Acoustics Sierra Reference in the past, the Sierra Aluminum headphone was not something completely new and unfamiliar. The physical design was essentially the same, save for the aesthetic differences that come from differing materials. As the name suggests, the Sierra Aluminum features an aluminum frame, which gives the headphone a distinctly industrial look. The metal isn't polished to look completely solid, and instead has a rougher, washed finish to give it a natural design. The honeycomb caging that the driver sits behind, plus the metallic shell, is definitely a sleek design that catches your eye in any environment. The more I had it on my desk during testing, the more fond I grew of the design. 

In terms of comfort, the Sierra Aluminum was just as comfortable as the Sierra Reference. Since the overall shape and size are the same, you'll find that the Sierra Aluminum provides the same level of comfort and fit as its predecessor. The Sierra Aluminum weighs in a bit heavier than the Sierra Reference, which could be a good or bad thing depending on your comfort preferences. I liked the slight extra weight of the Sierra Aluminum, giving the headphones a more luxurious feel. 

The Sierra Aluminum is not too difficult to drive, but they definitely benefit from an additional amplifier. Using DAC/Amps like the Chord MOJO 2, the iFi Gryphon, or the desktop K15 from FiiO were all great accessories to the Sierra Aluminum and gave it the power it needed to reach its full potential. 

• Weight: 400g Headphones (Without cable)
• Housing: Polished Solid Aluminum 
• Construction: Nylon, Aluminum, and PETG
• Driver: 50mm Paper Cone Dynamic Driver
• Impedance: 20 Ω at 1kHz

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

SOUNDSTAGE & IMAGING

Now for the listening review. The Sierra Aluminum presents a very large soundstage, really expanding the horizontal space to create a wide stereo image. You are put right in the center of your tracks, with the sound surrounding you on the sides and expanding up and back. The headphone presents an effective wall of sound that is entertaining and really blocks out the world around you. The imaging itself isn't the most accurate, but you are still able to place instruments in front of you quite well. There is a distinct separation to make individual elements have their own moment without being overshadowed by something else. I felt like I was in the middle of my listening, with a wide horizontal sound, and then at a fairly decent height. 

In terms of an overall signature, the Sierra Aluminum is very balanced and dynamic. Across the frequency ranges, you could hear how all of them matched in energy and power to create a fairly even picture right in front of you. I liked that it wasn't a flat image in front of you, but instead something with bright highs and punchy lows that created a very entertaining signature. You can run a bunch of different genres through these headphones and be met with natural, honest timbres in the sound reproduction. The signature may not be fit for reference listening and mixing use cases, but you'll definitely be able to do some analytical listening to catch all the minute details.  

BASS FREQUENCIES

Now we look at the individual ranges. The bass frequencies stand out as an excellent feature and highlight of the signature. The bass frequencies are really prominent and punchy, coming in to take up a lot of space on the low end of the frequency spectrum. It isn't overwhelming to be the only thing you notice or the defining characteristic of the sound signature. It takes a textured approach and focuses on the details and character of all the instruments as opposed to just the body. I liked that the bass had a good amount of depth and overall warmth that made a great foundation for other frequencies to build up from. I was able to appreciate all the tonal differences of the low-end instruments, with their textures and timbres being easily produced and identifiable. 

MIDRANGE FREQUENCIES

The midrange frequencies are forward in detail and push the vocals to the front of the soundstage. The layers and depth of the soundstage become more noticeable in this range, creating separate spaces for all the instruments that can make the mids crowded.  You get a lot of detail in these layers, and the textures come through easily to make analytical listening possible. Large instrumental ensembles were very fun to listen to, especially orchestras that had a lot of midrange detail. Instruments got their own spaces to shine without being overpowered by one another, and with the excellent imaging provided, you could really picture everything right in front of you and wrapping around you. The reproduction of these midrange instruments feels natural and honest, but there is still an added color to make listening fun and interesting as opposed to flat. 

TREBLE FREQUENCIES

The treble is bright and has a lot of color that rounds out the signature. I wouldn't say it is the most prominent part, but the aluminum housing makes the bright frequencies stand out a little more. The treble range carried through the whole signature to make all the elements a bit brighter and more precise. You could also hear the space in the soundstage with the openness in the top end. I liked how instrumentals got a burst of openness and brightness in the ultra-high range, where you could hear the reverberations of instruments in the space. It was a great complement to the low end, and it made the signature feel whole and balanced.

Looking at the other option by Auribus Acoustics, it makes sense to see how the two compare. With the Sierra Reference being $400 cheaper than the Sierra Aluminum, are you missing out on a huge jump in quality by going for one option over the other? The biggest difference between the Sierra Aluminum and the Sierra Reference is in the sound signature. The Sierra Reference sounds as the name suggests, with a flat response that is neutral and very natural. It is a headphone that is made for your audio mixing and analytical job. The Sierra Aluminum is a bit more dynamic and fun, with an added flair and color to make it more for entertainment. The shiny aluminum frame gives you an aesthetic difference, and it clues you in to the sonic differences between them. The brightness of the Sierra Aluminum is different from the Sierra Reference's more laid back and even presentation, and both are heavy in detail, so you aren't missing a thing. 

The Sierra Aluminum headphone is an excellent choice for audiophiles looking for something different. The shape of the Auribus Acoustic headphone will be familiar to those who know the design, but anyone who is just being introduced will be pleasantly surprised by the comfortable fit. The headphone isn't very hard to drive, but it pairs well with any DAC or amplifier to complement the already dynamic signature. I enjoyed this headphone quite a bit, and I would highly recommend this headphone to someone not afraid to dive into something new and unexpected. 

The Sierra Aluminum headphone is available at Audio46.