* This page is to purchase a pair of speakers
* Package price discounts will display in the shopping cart

** For a nominal fee, we will take a full suite of CEA-2034 measurements of the speakers you are purchasing using our Klippel NFS. Results will be emailed to you in a PDF file. We can also provide the raw data in text format.

** Note: NFS measurements take ~6 hours per speaker, as such these are not refundable.

Our Latest And Greatest Bookshelf Monitor

Class-leading bass extension, massive dynamics and midbass punch, high power handling, exceptionally wide and linear dispersion combined with some of the best measurements in the industry, our new LX is truly something quite unique and special.

This is the first ID audio loudspeaker fully designed and optimized using the most advanced acoustic analysis device on the planet, the Klippel NFS. The results are obvious, but even measurements as good as these are incapable of truly describing the dynamic capabilities of the LX.

These are not your typical bookshelf speakers, they sound like large towers and with enough power, are capable of filling large rooms with clean, detailed and exceptionally accurate sound reproduction.

---> Now with tunable bass, new Q-Plugs included at no charge!

To read about the development of the LX, click here: LX Development


100% MONEY




Project LX started well prior to Covid and quickly established itself as our most technologically advanced. It was our goal to offer something a bit different, different for us and especially different from nearly all other current loudspeaker offerings.

Our design goals were simple to describe, and partially based on performance standards prior to loudspeakers being designed for accuracy, a time when loudspeakers were designed for room-filling energy, bass, slam, and fun. More specifically, we want listeners to have that live-music feel, where the listener is having fun, becoming energized and emotional, and not “listening” for ultimate detail or accuracy (no one cares about those qualities at a live concert)

  • Power handling: the ability to handle huge amounts of power, thus producing high SPL’s while remaining clean without dynamic or thermal compression.
  • Slam: the ability to physically feel the pressure waves produced. In more modern terminology – massive midbass punch.
  • Deep bass: no additional description needed.
  • A big room filling sound: this requires wide dispersion, both horizontally and vertically.

This new speaker must also have the following characteristics in order to bear the name Ascend Acoustics:

  • Smooth detailed highs, no harshness or listener fatigue.
  • Accurate transient reproduction, little stored energy.
  • Transparency, reductions in resonances for the cabinet itself and the transducers. Assuring no extraneous distracting additional sounds are manifested.
  • Compact size, like all Ascend speakers – as space becomes a premium few consumers have the room these days for large speakers.
  • Good on and off-axis measurements.

Research began and then in March of 2021, we made the largest single investment in our R&D capabilities imaginable. A hugely expensive advanced acoustic measurement and analysis device called the Klippel Near Field Scanner. Very few audio manufacturers own one and we are most proud to say that with our NFS and combined with our other measurement gear, Ascend Acoustics has one of the most advanced acoustics labs on this planet.

the NFS was designed as an R&D device, producing the highest resolution, true anechoic 3-dimensional near-field and far-field response measurements. When properly configured and with enough experience, the data it can produce is leagues beyond any other acoustic measurement device and the capabilities of the NFS in the hands of an experienced engineer are near endless. The NFS also gives us the ability to deeply analyze an individual transducer, to truly “see” what makes it sound good or bad, where improvements can be made.

It then became our intention to use our NFS to fully design and optimize project LX, applying the most advanced science to old-school performance goals. Giving the LX superb detail and accuracy, ideal directivity combined with exceptionally wide dispersion while still keeping the old-school performance goals.

We analyzed the best ribbon and dome tweeters, looking specifically at linearity, directivity, power handling and distortion. Deeply evaluating the best characteristics of these tweeters to establish a set of specifications for what would be used for project LX. With the data on hand, we approached several top tier manufacturers and eventually SEAS provided us with a tweeter that not only met these stringent specifications, it surpassed them!

We then had SEAS implement a few minor customizations to the stock version, but little changes were needed.

Meet the LX tweeter:

Ascend LX Tweeter


Woofer selection was a bit easier. We had SEAS build a custom model for us based on specific specifications:

  • High power handling
  • Best-in-class bass extension and midbass punch
  • Specifically tuned for our Sierra-1 / Sierra-2 cabinet and port tuning
  • Copper shorting rings for reduced inductance and lower distortion
  • High excursion

As it turned out, SEAS also had a new 6" woofer as part of their Titan series, it is basically an improved version of the highly regarded L16RNX, the L16RNX3. This new version has a higher performance lightweight aluminum cone, titanium former and increased excursion.

To further meet our requirements, the engineers at SEAS recommended using the larger and more advanced magnet system from the L19, (a 7” version of this woofer.) This would provide even more slam – which was exactly what we were looking for. Additionally, rather than use the standard aluminum frame, we thought it best to use our custom tooled cast magnesium frame for additional stiffness and resonance control.

The result was remarkable… very deep bass and midbass punch in a small cabinet combined with exceptionally low distortion and ideal directivity. This unique version of this woofer is exclusive to Ascend Acoustics.

Meet the LX Woofer:

Ascend LX Woofer


This woofer seemingly defies physics, it hits harder than many 12" woofers and is a perfect match with the tweeter. Distortion is kept under control even below port tune frequency.

The LX are suitable for critical 2-channel music listening (both near-field and far-field), dynamic movie soundtracks, truly immersive gaming, jamming out to any music genre imaginable and even annoying those pesky neighbors if need be….   There is no source material that is too complex or dynamic, everything sounds terrific with loads of detail and the soundstage produced is huge. At even ear-damaging volume levels, these speakers keep their composure and never sound harsh or strained.

Hand assembled, tested and packaged in the USA, we are so confident of the component and build quality of the Sierra-LX that we are backing it by a comprehensive 7 year parts & labor warranty. Left / right pairs are matched by hand to within ± 1dB and we are including a full-range printout of the actual production line response measurement of each speaker.

We dare say it, but you simply cannot find this type of quality control, care and pride from products that are fully assembled and tested in overseas manufacturing facilities.

We thank you for your interest!



  • All Sierra-LX are hand assembled, tested and packaged at our factory in Orange County, CA
  • A full range serialized production line frequency response measurement is included with each speaker
  • 7 year manufacturer's warranty + 30-day satisfaction guarantee


  • Exclusive vertically laminated bamboo cabinet construction dramatically reduces cabinet resonance for a cleaner, more detailed, and transparent performance
  • Cabinet is a stunningly beautiful natural hardwood finish, there are no veneers and as such, no need to be concerned about peeling veneers or wraps or veneer cracks
  • Cabinet is fully environmentally friendly as the bamboo we source is a completely renewable resource
  • 3 different bass tunings available to suit every possible room, please see here for info: Q-Plugs
  • Unlike MDF, our bamboo cabinets are formaldehyde free (nearly all speaker cabinets use MDF)
  • New!  Stunning fully magnetic grilles with no visible grille posts.


  • Fully custom manufactured by SEAS of Norway to our specifications and exclusive to Ascend Acoustics
  • Class-leading excursion, maximum peak-to-peak travel of a massive 22mm
  • Titanium former for improved damping, better transient response, and massive power handling.
  • 2 layer pure copper 39mm diameter voice coil
  • Custom cast magnesium frame for a stiffer and lighter basket frame allowing for less material behind the woofer cone reducing back-wave reflections for enhanced detail, better airflow and less cavity resonance
  • Radially reinforced surround reduces surround resonances at higher excursions and provides for better overall damping
  • Exceptionally large magnet system combined with symmetrical driving force
  • FEA optimized magnet system with fitted copper rings for excellent linearity, low distortion and very low inductance
  • Vented pole-piece and open spider for enhanced air-flow and cooling, minimizing compression artifacts
  • Lightweight optimized aluminum cone is extremely stiff pushing breakup modes several octaves above crossover point
  • Woofer cone acts a pure piston throughout its usable frequency band, providing excellent directivity


  • Customized version of SEAS Titan dome tweeter
  • Anodized aluminum/magnesium dome enabling pistonic behavior throughout the audible range
  • Titanium former for improved damping, better transient response, and massive power handling
  • Copper cap in the magnet system for lower inductance and reduced distortion
  • Large damped and tuned rear chamber for absorbing back-wave energy and lowering the resonant frequency
  • Integrated hexagrid protects the dome while improving dispersion
  • Very high power handling and a low Fs
  • Extremely wide dispersion with near ideal directivity


  • Large open topology with proper inductor spacing and orientation to reduce mutual inductance and saturation
  • Heavy gauge pure copper traces to reduce resistance and provide higher power handling
  • Featuring metallized polypropylene capacitors
  • Air-core inductors in the direct signal path



Typical In-Room Frequency Response 28Hz - 23kHz
Typical In-Room Sensitivity 87dB @ 2.83v / 1 meter
Nominal Impedance 8 ohms
Max Continuous Power* 350 watts
Max Short Term Peak Power* 500 watts
Cabinet Detail Exclusive V-LAM™ construction featuring 20mm thick vertically laminated bamboo, internally braced. Bass reflex via flared rear port tube. Fully magnetic grilles.
Tweeter Customized version of SEAS "Titan" dome tweeter, with titanium former, 26mm aluminum/magnesium alloy dome, large tuned damping chamber and copper cap for reduced distortion and inductance
Woofer (1) Proprietary 6” high excursion, high power, aluminum cone woofer, non-resonant cast magnesium basket frame, vented pole-piece, dual layer pure copper voice coil, copper shorting rings, vented spider and titanium former. Custom manufactured for us by SEAS of Norway and exclusive to Ascend Acoustics
Connections (2) gold plated all metal 5 way binding posts
Inserts 1/4-20 threaded insert for securing to our TP-24 stands
Bass Extension (-6dB) 36Hz
Anechoic Frequency Response 43Hz - 23kHz +/- 3dB
Anechoic Sensitivity 83dB @ 2.83v / 1 meter
Dimensions H x W x D** 14.25" x 7.5" x 10.5"
Speaker Weight (each) 21 pounds
Shipping Weight (pair) 48 pounds
Minimum Recommended Amplifier Power Rating for Speaker Distance to Listening Position
3 Feet or Less 3 watts minimum
9 Feet or Less 33 watts minimum
15 Feet or Less 90 watts minimum
21 Feet or More 180 watts minimum
     *Unclipped peaks      **Grille On



* The below anechoic measurements are high-resolution full-range 360-degree scans taken with our Klippel Near Field Scanner.  A minimum of 800 individual measurements are taken to generate these advanced measurements, typically requiring a minimum of 6 hours.  These are unsmoothed and fully conform to CEA/CTA-2034 standards.

These measurements are as accurate as is currently technically possible.

Due to the costs, space requirements and complexity, very few manufacturers own or have access to a Klippel NFS, nor would they ever publish such detailed data on their products. Ascend Acoustics is and always has dared to be different.

For information regarding the CTA-2034 standard, please click here: CTA-2034

For information regarding the Klippel NFS, please click here: Klippel NFS Video and Technical Data


Sierra-LX On-Axis


Sierra-LX CEA-2034


Sierra-LX PIR


Sierra-LX Early Reflections


Sierra-LX Contour Plot Horizontal


Sierra-LX Beamwidth Horizontal


Sierra-LX Contour Plot Vertical


Sierra-LX SPL Horizontal


Sierra-LX Impedance and Phase


Sierra-LX Off-Axis PIR

*Note: Our exclusive Off-Axis Estimated In-Room Response measurement is a critical performance metric. It is an accurate comparison of the differences a listener should expect to hear sitting at different off-axis angles from the speaker; on-axis, +/- 10 degrees horizontally, +/- 20 degrees horizontally and +/- 30 degrees horizontally.

This is a modern and more accurate prediction of in-room speaker performance at different listening angles compared to a simple off-axis measurement graph. This measurement graph accounts for both direct sound and indirect sound and requires thousands of individual off-axis measurements that are then processed through complex algorithms to derive the results. In comparison, an off-axis measurement is just a single response measurement that does not account for the actual directivity of the speaker and is not representative of what we actually hear.

This measurement clearly shows the remarkable off-axis response of the LX. There is less than 1/2dB of deviation between the different off-axis positions and this is based on accepted science determining what the listener will hear from this speaker in a typical listening environment.



The Sierra-LX are truly unique speakers, offering a level of overall performance previously not obtainable in a passive bookshelf speaker. Most high-end loudspeakers focus on optimizing a few performance categories, the LX are class-leading in nearly every performance category. The only sacrifice made is with sensitivity, thus the LX will require a bit more power than typical - but with today's affordable high powered amplifiers, this is not an issue.

In many ways, this is an old-school design philosophy, completely modernized with the most advanced R&D available, combined with the latest transducer technologies. The results are simply spectacular. The LX sound HUGE, they project a soundstage that belies their small size, with dynamics, bass extension and slam that exceed most tower speakers - yet they remain extremely transparent, detailed, easy to listen to at even insane volume levels.  Even their accuracy / neutrality is unmatched.

We have been known to set the bar for performance, and with the LX - we have once again set that bar, and it is impossible to catch. We strongly encourage you to give these special speakers a listen...


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