Stenheim Alumine Two.Five

REVIEW
Eric Neff
Feb 26, 2025

One of the highlights of reviewing is an unexpected opportunity to spend time with a kit from companies you have admired but not had a chance to get in-house. That opportunity arose with a call from our editor to see if I was interested in reviewing the new Stenheim Alumine Two.Five floorstanding speakers. Stenheim speakers had always caught my ear at shows. They were always precise, coherent and seemingly able to pair well with any quality gear they were shown with. If I was unable to go to the canton of Valais in the Swiss Alps to visit Stenheim, then a small piece of Switzerland could visit me in Wisconsin.

I first encountered the Alumine Two stand-mount speakers ten years ago at Axpona. The room was not large, but the soundstage was well-defined, and the overall presentation had me sit down for an extended listen. I had not encountered them previously, and I came to find out the company had been started only four years before, in 2010, with the Twos arriving on the scene in 2011. An auspicious debut, to be sure.

Pay attention

Someone else was paying attention to this nascent company. Jean-Pascal Panchard was an engineer at Nagra. He also owned an audio store and was a long-time member of an active Audiophile club. As a lifelong audiophile, he took notice of the Alumine Twos when they were showcased early on at one of the audio club’s events. Jean-Pascal was so impressed that he acquired the company and is now the CEO and chief designer for Stenheim.

Stenheim Alumine Two.Five main

Getting to the heart of Jean-Pascal’s attraction, the Alumine Twos were a simple design that delivered a supremely coherent sound with smooth delivery. Their use of aluminium for the enclosures in panels brought a few advantages. First, they had very little enclosure vibration compared to other speaker cabinet materials. Next, the aluminium did not add any coloration to the sound. Coloration hides the information in the music. Finally, the aluminium panels were thick enough to be inert yet not so heavy as to be impractical.

Fives and Threes

The Stenheim line grew to include the Reference Line and the Alumine Fives and Threes. There was, however, room for one more speaker in the Alumine line. Enter the new model Stenheim Alumine Two.Five! Jean-Pascal and the team asked what if they took the primary Alumine Two stand mount design and crossover and added more cabinet space to enhance the bass response. During the design process, they added a second bass driver while retaining the two-way crossover to reduce complexity.

The ported design choice echoed Stenheim’s other speakers, allowing for greater bass extension without the additional engineering challenges of sealed speaker designs. The careful decision allowed for an additional 10dB in bass response versus the Alumine Twos and created a very room-friendly sized tower design that can blend into nearly any room. Colour choices include Dark Grey, Light Grey, Black, Ivory and Mocca, allowing easy integration with various décor.

Design magic

Part of design magic is knowing where to make critical choices. The decision to stay with a Two-Way crossover in the Stenheim Alumine Two.Five is one thing. Not compromising on parts is another. Each part choice involved decisions on quality (always high!) and sonics. Listening tests were required for each choice throughout the design process. The Two-Way option may have led to a simpler design but never to a compromise on sound quality or coherency. The drivers are manufactured to company specifications, and they are paper for the bass drivers and silk for the tweeters. Paper is used for its comparatively light weight and rigidity.

Each driver is specially coated with a company-specified chemical treatment to achieve the desired performance goals. The placement of the drivers is also not in the centre of the speaker front. They are each slightly offset toward the inside of each speaker. There is a specific Left and Right speaker in each pair. The bass ports are also off-centre towards the outside as the enclosure design uses their placement to optimise the bass response and functionally reduces any port noise to zero.

The speakers are shipped with floor spikes and floor saver discs to allow room coupling and adjust the listening angle as needed. The spikes and discs came with installation tools and were installed easily. At 45kg each, the Alumine Two.Fives are easily manageable for two people to set up. Given their high build quality and solid aluminium enclosure, the Alumine Two.Fives are built to last. The warranty is five years; however, the expected lifespan is much longer.

Revealing

Getting down to some listening, I queued up, via Qobuz, Sophie Zelmani’s ‘All About You’ from her 2011 album, Soul (Epic). This well-recorded song features gentle acoustic guitar work, laid-back drums, and bass guitar backing Sophie’s soft vocals. The Stenheim Alumine Two.Five disappeared as the intimate club space revealed itself. Fingerwork on the guitar strings was complimented by subtle Hammond B3 keyboard playing. The depth was remarkable, and the band members’ physical location was clear. You could sense the spotlight on Sophie and the smoke from the ashtrays from nearby small tables. When a recorded song becomes a performance, a ‘you are there’ experience is rare and beautiful.

Next up was George Benson’s ‘Turn Your Love Around’ from his George Benson Collection vinyl record (2009 Rhino/Warner Records). This song brings the dynamics. Brass and backing vocals surround George’s beautiful tenor voice on this US top-five hit. The stage was filled with a who’s who of top session musicians and an all-star group of solo performers. George’s voice was delicate and soulful during the verse, and the full stage of singers and musicians launched the chorus’s crescendo. Brass came through with the brash tone expected of top trumpet and flugelhorn. There I was, sitting in the tenth-row centre, enjoying the show. It was a satisfying presentation.

SACD switch

I switched to SACD and selected the title track from Donald Fagen’s Morph The Cat (2006 Reprise). The bass line in this classic track drives the tune, and I enjoyed how solid and impactful the bass was presented from these slender, smaller tower speakers. At a specified 35Hz low end, the bass was solid and well defined. The sax solo had the necessary rasp and timbre. As I moved through various musical genres, I continued to appreciate the versatility of the Stenheim Alumine Two.Fives. Each was represented well by soft, dynamic, solid grooves and vocals, and the recording space was always as well-defined spatially as the recording could offer. The Alumine Two.Fives were not so much an interpreter of the music as a window to the recording, allowing me to appreciate what each artist wanted to convey fully.

Moving on to rock with a dose of metal, I put on the Redbook CD of Beauty and Rage from the band Red (2015 Essential Records). Track three, ‘Shadow and Soul’, is a great example of orchestral metal featuring the band backed by a full string section of violins, violas and cellos. While you get the crunch of rock guitars, they are framed by sweeping strings and piano. It is a vast and wonderful sonic envelope offering great scale and volume. Mike Barnes goes from crooning to screams as the song progresses.

Never flinching

The Stenheim Alumine Two.Five never flinched presenting the instruments with clarity. Strings came through as textured, and the vocals were clear and strident as intended. This is a dense track, and I kept thinking about the primary precept of Stenheim, which is a commitment to coherency. Tracks like this would suffer if there were anything ‘off’ about crossover design, driver specification, or cabinet stability. Instead, the song came through as a tapestry of sound. A complete work where you could appreciate the whole or the parts with equal pleasure. Bravo Stenheim!

Wrapping up the listening, I turned to the DVD-Audio title track of Linda Ronstadt and the Nelson Riddle Orchestra disc, What’s New (2002 Elektra). Ronstadt, a transcendent vocal talent whose career was cut short by illness, is at her peak in this recording. Backed by a superb touring orchestra, she presents the song with nuance and power. Centred in front of the stage with the orchestra surrounding her, the song is beautiful, and the sonic presentation is a masterclass in how to ‘mic up’ a singer and orchestra.

The instruments frame her vocals, and she becomes the peak of the musical mountain, her clear and powerful voice delivering as beautiful a presentation of this song as I have heard. Clear, coherent and inviting, I was drawn into the music. I stopped enjoying the moment the disc had run its course, with all nine songs having been thoroughly appreciated. Originally recorded in 1983, it is as stirring today as it was when it was released. Enjoying it on the Alumine Two.Fives was a special treat.

Power agnostic

Deciding on a new speaker involves so many choices to be considered. Not the least is how much power they require to offer their full capability. Fortunately, the Alumine Two.Fives are an easy 8 Ohm load with a sensitivity of 93dB and can be powered by as few as 10 Watts per channel. They can also thrive with big amps like the Sanders Sound Systems Magtech, offering up 500 Watts per channel into 8 Ohms of fully regulated class AB power. This almost power-agnostic aspect of the Alumine Two.Fives makes them an available option for nearly any amp choice. Listening to them with my Cary Audio CAD-300 SEI’s 15 Watts per channel of class A triode 300B tube power proved very satisfying. The Atma-Sphere Class D mono’s offering up 100 Watts per channel also paired beautifully with the Alumine Two.Fives.

Rarely have I encountered a loudspeaker that was so wonderfully adaptable when paired with various quality power amps. Both the Sanders and the Atma-Sphere amps ran through my Pass Labs preamp. Shiny discs were all played on my Oppo-205 via the Geerfab Audio D.BOB into a Cary Audio DMS-700 DAC/Streamer.

Stellarly

It mattered not to the Alumine Two.Fives, whose electronics I paired them with, presented stellarly in all cases. Many speakers require more careful gear matching. Stenheim Alumine Two.Fives are less concerned with who they work with and will deliver the best of what you give them. This is a speaker to build your forever system around.

Slightly more than a decade after its founding, Stenheim has won many awards for Best of Show and Design Innovation. Their most recent successes were Best of Show awards at Axpona and Munich in 2024. What is most impressive for me is that they gather accolades for their flagship Ultime Reference line and across all of their offerings. Each model is important as its own unique entity. Each model receives special attention to achieve the Stenheim level of quality. Whatever model you select carries the full weight and pride of the Stenheim brand. That is the key, as the Alumine Two.Fives are the single best pair of speakers I have ever auditioned in my listening room, regardless of price or system pairing. Yes, they are not inexpensive, but you very much receive the commiserate quality you are paying for. Highly recommended.