Auribus Acoustics Sierra Review – Headfonia

This is the review of the Auribus Acoustics Sierra headphone. It is selling for $1,200 USD.

Disclaimer: The Sierra headphone was sent to me by cma.audio in exchange for our honest opinion. I thank them for their generosity.

Auribus Acoustics

Aurisbus Acoustics is a reasonably new name in the market, even though they started back in 2019 already.

On their website we find the following: Auribus Acoustics is a high-end headphone startup based in Southern California, where we combine exceptional industrial design with advanced audio technology. Our goal is to craft a new class of hand-built headphones that meet and exceed the demanding standards of audiophiles. 

What began as a university hobby project in San Francisco evolved into a company driven by innovation. Early prototypes, refined through feedback from trade shows, led to the incorporation of the company and the successful launch of our first product, Everest, which ran from 2023 to 2024.

Now, with the release of Sierra Reference in 2024 and Sierra Aluminum in 2025, we continue to build on our foundation of quality and craftsmanship. This latest model integrates advanced 3D printing technologies throughout. This approach allows for an unparalleled user experience and manufacturing flexibility, enabling us to meet the complex demands of the high-end audio market.

In this review we take a close look at the Sierra Reference. Let’s get started!

Sierra

As mentioned above, the Auribus Acoustics Sierra isn’t new but at the same time it still is, at least here in the EU.

I first listened to it at the High-End Munich show back in 2025, and to be honest I really disliked it. It just sounded horrible at that show. I then listened to it again at the WHO show in Essen later that in the year, and there it sounded good.

Sierra is a new take on the possibilities of open-back, dynamic driver headphones for audiophiles and studios alike.

I can only imagine that someone messed up the source tuning at the Munich show, which made the Sierra sound overly heavy, bloated and uncontrolled. Anyway, I’m glad I listened to it again, and as such we’re now covering it on Headfonia, thanks to cma.audio.

The Sierra is an open-back over-ear headphone and according to Auribus, it was designed for uncompromising music lovers and professional users alike. On the inside we have 50mm Peerless™ Paper cone Dynamic drivers that according to the company deliver a detailed, fast sound with natural timbre and extended sub-bass range. More on that later.

True to life accuracy and impact, all day comfort.

Tech wise, the Sierra has a couple of interesting features. The new 3D Baffle is a spacious cavity with the driver pointed at an optimal angle towards the ear. Auribus combines it with a precision cut acoustic lens.

Another highlight are the electric filters, which optimize sub-bass and treble, providing exceptional control and a pleasantly balanced tonality. And then there are the excellent Elite Hybrid Leather/Velour Pads pads from Dekoni. These pads are deep, soft, breathable, and they perfectly seal.

The Auribus Acoustics Sierra sets new standards in headphone development. Combining innovative technology, high-quality workmanship, and exceptional sound, it offers an outstanding listening experience for discerning users. Whether for private music enjoyment or professional applications, the Sierra is an excellent choice for anyone who values quality and innovation.

As you can clearly see in the picture, the Sierra is a 3D printed headphone, but more on that later. Connection wise it used 3.5mm mono connectors that sit at the back of the ear cups. If I’m not mistaken, Sierra’s driver is not exactly new, and it has been used by other makers. It’s all about the implementation though, so let’s keep an open mind.

If you want to find out more about the specific tech and features, you can do so on Auribus Acoustics website here.

Box, Accessories, Price

The Sierra headphone comes in a very simple, basic white box and you immediately get that homemade feel from it, at least it does that for me.

On the inside of the box, there is a padded carrying case in which Sierra’s cups nicely fit when rotated 45°. It’s also all that I received, but you will normally also get a 1.4 Meter 3.5mm or 4.4mm to dual 3.5mm termination cable. The Dekoni Elite Hybrid Leather/Velour Pads come preinstalled as usual.

According to cma.audio you also get a cable clip for attaching the cable to your shirt collar, but I’ve never seen that myself. I’ve been using the Sierra with Meze Audio’s Dual Mono 3.5mm Copper PCUHD Premium Cable, as the stock one wasn’t supplied.

The Auribus Acoustics Sierra is selling for $1,200 USD or €1.399 EURO, which puts in the medium to high-end range. Purely looking at the delivery, accessories and 3D-print/build quality, that’s perhaps a bit steep, but let’s see how we feel about that after we’ve looked at how it performs and sounds.

Design, Build Quality

I like Sierra’s design. The grill, earcups and headband just look cool and it’s not “just another headphone”. It really draws you in with its looks. Especially the grills and dual tone headband are what do it for me.

As said, it’s clear that this is an in-house built headphone, but it’s nicely done and really cool in that regard. All Auribus’ headphones are handmade in California and on their site, we find the following about the production process:

The entire assembly is crafted from advanced polymers and aluminum for a durable, repairable, and lightweight assembly. This headphone has been years in the making and represents a generational leap in our ability to design and assemble a high-quality product in-house.

Thanks to an innovative mix of nylon, aluminum, and PETG materials—manufactured using a high-precision SLS 3D printing process—the Sierra combines a robust, comfortable lightweight design (made of nylon, aluminum, and PETG) with audiophile finesse.

The 2025 Sierra revision includes an improved headband with a smooth swivel mechanism, along with an optimized driver enclosure for improved mechanical and acoustic consistency. The Sierra headphones are built to order, and non-Standard colors must be requested via email, and are subject to surcharge. 

The Sierra does have replaceable components, cables, pads, and the headband can be easily replaced or adjusted as needed. That said, the Sierra has a robust look and feel, and I’m pretty sure it can take a serious beating before anything breaks. I don’t see my unit needing replacement parts anytime soon.

All-in-all, I like the design and the build quality is good but compared to a “regular” +$1K headphone, it feels basic. That however is part of the charm and the philosophy behind it. If you however don’t find it acceptable for a headphone of this price, I also perfectly understand.

Sound

Sound – Introduction

This is the section where we find out how the brand describes the sound signature of the unit in question. For the Sierra, we find quite bit of descriptions and measurements.

The Sierra offers a balanced, relaxed yet high-resolution sound signature with strong spatial imaging:

• Sub-bass: Surprisingly powerful for an open design – precise and controlled

Enjoy a spacious, detailed sound contrasted by the intense impact of subwoofer-like bass thanks in part to the Patented (Pat. 12,395,780 B2) Linear Extension system.

• Mids: Natural, true to color, perfect for vocals and acoustic instruments
• Highs: Gently present without harshness – detailed but never tiring
• Spatial imaging: Wide, realistically layered, with clear localization and no exaggeration

The tonality remains controlled even at higher volumes – ideal for longer sessions without sonic fatigue. Sierra delivers a sound that is deeply moving without being overwhelming.

The new 3D Baffle is a spacious cavity with the driver pointed at an optimal angle towards the ear. In combination with a precision cut acoustic lens, the result is an accurate and expansive soundstage, creating a truly immersive music experience.

The 50mm Peerless™ Paper cone Dynamic drivers and an open acoustic structure make for a beautiful and natural tone across the spectrum. Enjoy incredible extension at both ends of the hearing range thanks to an updated version of the Patent Pending Linear-Extension System pioneered for the Everest

Let’s find out if any of that makes sense, and let’s see how it really performed during my testing.

Sound – Measurements

Before going into our regular subjective impressions, I first want to show the Sierra’s regular FR, as well as the comparison against the Harman curve, and the popular HD600.

Here we clearly see a boosted low end, as well the vocal section but it isn’t a typical v shapes signature either. The top end looks like the Swiss Alps with plenty of peaks and drops, but it doesn’t really reflect that when listening.

When compared to the popular Harman target, you can see the Sierra follows the curves nicely up to the 3K area, where it becomes peakier. Purely looking at this, the Sierra should be an easy to like headphone tonality wise.

The Sennheiser HD600 still is one of the most respected headphones on the market. While some praise it for its tonality, others find it a bit light in the bass department. As you can see here, the Sierra nicely flows the HD600’s curves, with an added lower end. That again means, this could be a big crowd pleaser with a tuning a lot of you have been waiting for.  

The part on sound continues on the second page. Click here or use the jumps below.