James Romeyn

AudioKinesis Sigma stand mount satellite, 96 dB, 4 ohm

Want to sell
As New (see details) 10 / 10
Price is per pair. Sigma images atop extra cost SuperStand not included in sale. Designed by Duke LeJeune. Select maple, light cherry or satin black (+$200/pr for the latter); request price for custom colors.

From the "About" page for professional bass player/acoustician/recording studio designer/recording studio engineer/Berklee School of Music graduate Cum Laude Jeff Hedback: http://www.hdacoustics.net/about/

"...Duke LeJuene...is special...not just brilliant and humble but seriously NICE...one of the world’s best electro-acoustic crossover network designers...offers boutique bass guitar cabinets, wonderful HiFi speakers and he and Jeff have worked on features and specs for several custom recording studio main speakers..." (emphasis added)

As of 2015 Stereophile Magazine Technical Director John Atkinson had tested over 750 loudspeakers (many dozens more since 2015). The average “sensitivity” of speakers Atkinson tested is 86 dB. AudioKinesis Sigma has “true” input sensitivity of 96 dB @ 1W @ 2.83V. (We say “true” because the higher is the published sensitivity spec the greater is it usually inflated, e.g. models Klipsch specify in the high 90s Atkinson measured in the low 90s; other brands may exaggerate similarly or to a lesser extent.)

What difference does 10 dB greater voltage sensitivity make to the prospective Sigma owner? To achieve the same acoustic power, each greater 3 dB of sensitivity cuts the required amplifier power in half. To achieve similar acoustic power Sigma requires 1/10th the amplifier power required by the average audiophile loudspeaker.

For an application with 40W driving Sigma the average audiophile speaker requires 400W for similar results. We say “similar” rather than identical because Sigma compresses dynamic peaks less than 1 dB w/40W input; virtually no affordable cone/dome speaker can safely handle 400W input power, and those that do compress dynamic peaks approximately 10 dB when fed power of this magnitude. Affordable cone/dome speakers capable of matching Sigma’s acoustic power is a short list.

Sigma’s higher sensitivity also makes it sound more dynamically alive at low levels wherein a cone and dome speaker may sound dynamically soft. The combined benefits of Sigma + its partnering amplifier is greater than the sum of the parts. Sigma sounds lively, as is more often the case with power amps of a lower power rating. Each product magnifies the other’s advantage.

Adjusted for inflation, the price per same quality amplifier watt has shrunk over time, yet this audiophile axiom remains: within the same budget class, the greater the rated amplifier power the less lively, refined and musical does the amplifier tend to sound. Audiophiles do not pay over $1k per exotic NOS 300B tube to heat their homes in the winter (8W output power). They pay that much for certain tubes because of the perceived audio performance. Possibly the most renown amplifier designer Nelson Pass has an entire range of ultra-refined, moderately priced amplifiers under the “First Watt” banner, the most powerful making about 25W. The name derives from the designer’s theory that the first watt is critical for realism and low-level detail otherwise masked by bigger amplifiers which tend to sound slower and less refined.

Any 4-ohm capable tube or SS amp is well suited to drive Sigma’s benign phase angle and 3.5-ohm minimum impedance (in the bass range). We recommend a minimum of about 20 tube watts and 40 SS watts.

Our target is supreme synergy between loudspeaker and its partnering amplifier, for the lowest possible cost. Once you hear such synergy you will know when it is gone, and you will not willingly settle. Infinite funds provide almost infinite solutions. The tighter is one’s budget the fewer are options and potential solutions. Owning a quality speaker like Sigma allows one to spend a lot less on the partnering amplifier and still achieve the desired quality and acoustic output. As someone with a persistent goal to crack a new performance per dollar record, IMO that formula starts with the highest sensitivity speaker that meets or exceeds all other minimum performance parameters, which bring us to the rest of the story.

The rest of Sigma’s design parameters enhance its value and performance. Sigma is a satellite requiring sub-woofer augmentation below about 55 Hz. Sigma is a precision 2-way with only one xo pole. The greater the number of xo poles the greater the opportunities to degrade performance.

Sigma employs a 13.5-inch wide, long-proven “Super Elliptical Oblate Spheroid” or SEOS (SAY-os) wave guide. Sigma’s radiation pattern is 90-degree horizontal x 45 degree vertical, with good damping of floor and ceiling reflections. With recommended extreme toe-in, side wall reflections improve performance instead of degrading it. In the critical “pass band” (range with shared output), the mid-bass and wave guide share similar radiation pattern. A bane of cone-dome loudspeakers is that each driver has mutually exclusive pattern in the pass band: the larger driver’s pattern narrows in the same range where the smaller driver’s pattern widens. The ear notices the unnatural quality and perceives it as a “box” effect.

Sigma lacks the ubiquitous “cupped hands” effect often associated with horns. Renown DIY Aerial speaker and tube amp authority Lynn Olson describes himself as being highly sensitive to such effects, and does not hear it in AK speakers.

Sigma pattern shape rolls out quickly and smoothly throughout the range, critical for sound quality.

The Italian Faital 8” mid-bass are high-performance pro sound drivers, employed in at least one ultra-high cost European domestic speaker. The British Celestion mylar compression driver is one of the smoothest, most musical and high-value drivers of its type, with a long and enviable reliability record.

Accommodates any listening perspective, far to near field. Appearance wise meets all AG "mint" 10/10 specifications.

5-year warranty; per industry standard burnt voice coils are non-warranty service (see "Amplifier Requirements" below).

Platform Height/Not Critical: ear height minus 13.25 inches (distance from Sigma's horn center to its 3M ISODAMP feet)

Due to Duke's improved crossover expertise, Sigma II outperforms original Sigma with all 4-ohm capable amplifiers. Pro reviewer comments: https://parttimeaudiophile.com/2015/10/22/rmaf-2015-audiokinesis-violates-space-and-time/

Long list of AudioKinesis review comments, all models, links to full reviews: https://jamesromeyn.com/reviews/

Several pages Re. AK build, design, philosophy, construction, etc.: https://jamesromeyn.com/audiokinesis-speaker-design/#philosophy

Ship within 1 business day after payment. Paint color options: 2.5 week delay for any custom automotive paint color. Add $200/pr for satin black, satin white or satin egg shell; please request price for any other color or sheen.

Vendor respectfully requests to split Paypal fees.

Add $120/pr for Cardas CPBP (copper) binding post in stock to replace standard input posts in images (one day delay).

Sigma designed entirely in the US. Sigma cabinet and crossover built and assembled in the US. Sigma final assembly in the US comprising parts from around the world including Italy. Safe and secure shipping in OEM wood crates (one per Sigma) with at least 2” foam all around. Inquire for shipping quote; vendor gets 40% FX discount and employs surprisingly affordable Concordia to ship international.

Return/refund conditions, no exceptions: full refund minus all seller out of pocket fees. Buyer must have merchandise in shipping company hands within two weeks after receipt of merchandise. Buyer must return merchandise in same condition received, and report any undisclosed blemish via typed message within 24 hours after receipt of merchandise. Buyer agrees to insure merchandise for full sale value and require receiver signature when merchandise is returned.


  • Crossover: 1.6k Hz
  • Net weight each: 51.3 lbs
  • Driver Layout: MHM mid bass/horn/mid bass
  • True Voltage Sensitivity: 96.0 dB @ 2.83V @ 1M
  • Toe-In: recommend on-axis lines intersect 4-6 feet IFO sweet spot
  • Wave Guide: 13.5-inch wide SEOS (SAY-os) Super Elliptical Oblate Spheroid
  • Mid-Treble Driver: Celestion compression driver, mylar diaphragm, 1-inch throat (Great Britain design)
  • Radiation pattern: 90-degree horizontal x 45-degree vertical, ideal for low and/or highly reflective ceiling
  • Input Impedance: 4 Ohm nominal, 3.0 Ohm minimum, benign phase angle, flat impedance above the bass range
  • Dimensions H x W x D: 26 x 18 x 10 inches, 45-degree angle on all 4 vertical corners (front diagonal 1.75” wide, rear diagonal 3.5” wide)
  • Mid-Bass Driver: 8-inch Faital pro sound from Italy, octagonal alloy frame, treated paper cone, accordion surround, neodymium magnet
  • Input Posts: single pair gold plated, lower most posts (upper posts are Treble Tilt controls), add $120/pr for Cardas CPBP copper (1-day delay to ship)
  • Amplifier Requirements: 4-ohm or lower impedance capable, suggest 20 tube/40 SS watts minimum, 100W or 200W input yields maximum output depending on use (see "Maximum Output" specs)
  • Bass Tuning: includes 4 air-tight easy to use Cherne brand "pipe plugs" per cabinet, plug 0 to 4 ports to help smooth the room’s bass mode effects. If 2 ports employed leave one port open per each 8” mid bass to enhance reverberant field energy
  • Footers: custom cut .25” thick x 1" diameter circles, blue w/black edge 3M ISODAMP used to damp MRI magnets, "duro" # matches Sigma weight, fastened with 3M reusable adhesive putty
  • 5 Position Treble Tilt Control: -2, -1, 0/Neutral, +1, +2; for each step a different value non-inductive power resistor fastens to the non-polarized uppermost binding posts, each step has a unique curve and gain to maximize control and tuning effect
  • Maximum Output @ 1M w/only 1 dB Dynamic Compression: 20 Hz full range input @ 100W yields 113 dB with 1 or more ports open; 200W yields 116 dB with all 4 ports sealed OR 1 or more ports open with 2nd order @ 80 Hz active high pass filter (not included)
  • System Design: mid-bass and waveguide radiation patterns matched in the critical crossover "pass band" (impossible with cone/dome patterns), 45 degrees vertical x 90 degree horizontal, fast and smooth pattern roll-off, four rear-firing dual-flared ports behind mid bass drivers enhance reverberant field energy

Sigma Cabinets:

  • All drivers flush mounted
  • Mid bass baffle 1.5” thick
  • Primary material: ¾” MDF both sides pre-veneered
  • Grille shape: vertically stretched octagon echoes mid bass frame
  • Furniture grade real wood veneer, multi-coat hand rubbed satin lacquer
  • Reinforcement: mass-loaded top and base panels, two full horizontal window braces (one each between wave guide and each mid bass)


James Romeyn

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