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Sierra-1 Speaker

The Sierra-1 continues in our tradition of offering sonic purity and accuracy while breaking new ground with several advanced new features and technologies.

Our objective was to follow a “less is more” philosophy to achieve accurate sound reproduction.  Less cabinet resonance, less distortion, less diffraction and reflections and fewer phase errors -- in other words, a major reduction of all the negative characteristics the loudspeaker itself imparts on the source material.

This lofty goal required the development of new measurement and testing methodologies combined with precision components designed to work in unison.  Most new loudspeaker models use the same components as previous models or make minor changes to the cabinet or a component and are then called “new and improved”.  In our opinion, adding another woofer or making the cabinet larger does little to actually improve overall performance. 

With the Sierra-1, every component has been painstakingly designed and optimized to achieve astounding performance.  From the cabinet material to the way the crossover is mounted, we firmly believe that the Sierra-1 is comparable to any bookshelf sized loudspeaker on the market today, from performance to build quality at any price point.

At The Heart Of The Sierra Is OPPIX™

OPPIX stands for Optimized Paradromic Phase Integrated X-Over (crossover). This sophisticated variable slope crossover precisely aligns the acoustic phase response of multiple transducers at the exact point where the response of one transducer crosses over to another, with reference to a specific point in space. This precise alignment allows the transducers to mimic a single point source radiator, allowing for symmetrical dispersion even with an asymmetrical transducer layout while maintaining a linear frequency response and greatly reducing off-axis phase and response anomalies. It also avoids the undesirable frequency response anomalies commonly found with even the best coaxial drivers.

arrow High-performance metalized polypropylene capacitors in the direct signal path, these offer lower dissipation than the more common polyester based film capacitors.

arrow Air-core inductors to reduce saturation effects combined with heavy gauge windings to reduce resistance and improve efficiency.

arrow Low inductance resistors to reduce distortion and provide accurate transient information.

arrow Linear impedance response for consistent performance regardless of amplification source.

arrow Isolation mounting, whereby the crossover is attached to the cabinet using isolation feet, which reduces the transfer of resonances from the cabinet to the crossover components.

Sierra-1 Crossover
Crossover Network

Exclusive V-LAM™ Cabinet Construction

In order to greatly reduce cabinet resonance and energy loss common with MDF enclosures, the Sierra-1 cabinet is made from vertically oriented laminated bamboo. There are over 200 individual sheets of ¼" thick bamboo, each laminated to another and arranged such that each panel is vertical forming a baffle that is 3/4" thick. This cabinet has extremely low resonance... Warning, perform knuckle-rap test at your own risk!

The inside walls are lined with top-grade damping material and each joint is well braced. We custom tooled a high-flow flared port tube which is flush mounted into the rear of the cabinet. All drivers are flush mounted to reduce baffle reflections and the front baffle vertical edges have a beautiful radius which aids in the reduction of diffraction.

Sierra-1 Speaker


arrow Bamboo is an environmentally friendly renewable resource. Ecologically, the harvesting of bamboo does not affect the world's dwindling timber resources. Technically considered a grass, bamboo has the ability to grow to maturity in only 3-6 years. The intricate root system remains unharmed upon harvesting and allows for sustainable future growth.

arrow Bamboo is incredibly strong and considered one of the most durable hardwoods. It has a tensile strength that is stronger than steel and the vertical orientation of the panels we use take full advantage of this.

arrow The bamboo we use is completely moisture resistant. MDF will swell when exposed to moisture and this is often the cause for the cracking and peeling of the various finishes applied to MDF loudspeakers over a period of time.

arrow All joints are well braced.

arrow All drivers are flush mounted to reduce reflections.


Why stop with exceptional accuracy? Why not improve accuracy while also offering a broader frequency range? Ascend loudspeakers have never been known for their bass response, but what if we could design a woofer that was capable of offering accurate and deep bass response while also being able to reproduce the delicacy of midrange frequencies?

This woofer took years to get “just right”. In the end, the final results speak for themselves. The combination of this custom designed woofer, low energy loss rigidity of the bamboo cabinet and the custom designed high-flow port tube provide an accurate bass response well into the low 40Hz range with exceptionally accurate transients.

arrow Custom 5.25” long-throw injection molded mineral-filled polypropylene woofer.

arrow Cast aluminum frame for exceptional rigidity and reduced resonance.

arrow Vented pole-piece and vented spider to reduce compression effects and increase compliance.

arrow Full size copper shorting rings for substantially reduced distortion.

arrow Low inductance motor for accurate transient reproduction and detailed mids.

Sierra-1 Woofer


In order to realize our goal of reducing the negative acoustic effects caused by each loudspeaker component, the Sierra would require a special tweeter. In addition to our typical requirements (linear on- and off-axis response and excellent extension), we demanded an exceptionally clean spectral decay combined with very low distortion.

SEAS engineers recommended a new tweeter currently under development that we could further customize to suit our needs. This new tweeter has a few unique features. It contains an integrated slightly elliptical wave guide made of flexible and absorbent elastomer. The subtle shaping helps control the off-axis response and aids in the reduction of diffraction, while the elastomer material helps absorb stray high-frequency wavelengths. The wave guide insert also has the added benefit of covering the magnet assembly screws, thus eliminating the pesky reflections these cause.

The tweeter also contains an extremely wide integrated surround which serves to better dampen the dome, thus reducing various resonances and break-up modes.

Sierra-1 Tweeter

Sierra-1 Tweeter

arrow Fully manufactured in Norway by SEAS of Norway.

arrow 26mm high-definition pre-coated fabric dome.

arrow Fully integrated slightly elliptical wave guide made from elastomer to reduce diffraction and control off-axis response.

arrow Integrated wide surround for reducing resonance and break-up modes.

arrow Low viscosity magnetic fluid for improved power handling and damping.

arrow Pole piece damping chamber to absorb back-wave reflections and lower the resonance frequency.

arrow Exceptionally clean spectral decay and low distortion for greater detail and improved accuracy.