AudioKinesis Sigma II 96 dB, shown atop extra-cost SuperStand

Price is per pair.  Sigma images atop extra cost SuperStand not included in sale. Designed by Duke LeJeune.  Select maple or satin black; 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 @ 2.83V (2W @ 4-ohm.  We say “true” because the higher is the published sensitivity spec the greater do other OEM's usually inflate that spec, e.g. models Klipsch specify in the high 90s Atkinson measured in the low 90s; other brands may exaggerate similarly.)

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 1/10^th the amplifier power required by the average audiophile loudspeaker.  400W > the audiophile speaker w/average sensitivity = 40W > Sigma.

Note that Sigma compresses dynamic peaks ca. 1 dB w/40W input; few to no affordable cone/dome speaker safely handles 400Wrms input power, and those that do compress dynamic peaks approximately 10 dB when fed power of this magnitude.  Sigma clean SPL exceeds that of any affordable cone/dome speaker.

Sigma’s higher sensitivity also makes it sound more dynamically alive at low levels wherein typical cone/dome systems 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 w/low to moderate power rating.  Each product magnifies the other’s advantage.

Adjusted for inflation the price per same quality amplifier watt 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 pay over $1k for exotic NOS 300B tube for its extreme  refinement @ 8W output power.  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 lack refinement.

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 or 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 the range of 80 Hz to 140 Hz (tunable via 8 ports per speaker pair and air-tight plug included per each port.)  Sigma is a precision 2-way with only one high-pass and low-pass xo.  The greater the number of xo poles the greater the opportunities to degrade performance; the ear has an acute sensitivity to more than one xo pole.

Sigma employs a 13.5-inch wide, long-proven “Super Elliptical Oblate Spheroid” or SEOS (SAY-ahs) wave guide.  Sigma’s radiation pattern is 90-degrees horizontal x 45 degrees 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 this 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.

The outermost edges of Sigma's radiation pattern are smooth, without sharp corners, critical for sound quality.

The Italian Faital 8” mid-bass are high-performance pro sound drivers, employed in at least one luxury, 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.

HOME THEATER APPLICATION

These simple facts are as true as they are seldom known: in almost every commercial movie theater the front L/C/R loudspeakers are behind and fire through a perforated screen.  Why?  Because in every single case and without exception a properly sited screen and front L/C/R loudspeakers always occupy the same height above the floor.  To ignore this rule is to degrade performance.

Virtually every vendor makes and sells at least 1 center speaker with architecture different from the associated L/R speakers.   This philosophy is based on a fallacy no matter the speaker cost.  Always and without exception: with a non-perforated screen, the C speaker and/or the display is some combination of too high and/or too low.  In any and every application with mismatched L/C/R speakers and/or a C speaker at different elevation from the L/R, performance suffers every time an acoustic object "pans" laterally across the front.  If you think the ear won't notice the gross and obvious differences when objects pan across 3 front speakers with varying architecture and/or @ different vertical heights, think again.  We're talking about different radiation patterns and sound sources at different heights.  DSP can't fix the resulting problems.

We recommend a good 4k or 4k enhanced projector, a retractable perforated screen and two high performance satellites ala Sigma with our Space Generator accessory speakers behind the main speakers.  Setup your HT system for phantom center.  (Works well for up a maximum of 3 seats across the first row.)  The phantom center performance will outperform any known C channel speaker; panning across the front is perfect and seamless

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

Ideal Platform Height/Not Critical: Sigma's perfect stand or platform height = ear height minus 13.25 inches (distance from the center of Sigma's horn to its 3M ISODAMP feet.)

Due to crossover advancements: powered by any 4-ohm capable amplifier Sigma II outperforms original Sigma.  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: http://jamesromeyn.com/reviews/

Several pages Re. AK build, design, philosophy, construction, etc.: http://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.  Standard price for satin black, satin white or satin egg shell; please request price for any other color or sheen.

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

Add $2k/pr for Radian true beryllium compression driver replaces standard polymer diaphragm CD.

Add $2k for V-Caps replacing standard audiophile polypropylene caps and 15AWG air-core mid-bass coil replaces standard 18AWG coil.

Internal Wire: Add $700 for all-Infigo Audio custom cryo cotton-insulation wire.

All above mods together: Discount $500.

Specifications:

• 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 (British design)
• Radiation pattern: 90-degree horizontal x 45-degree vertical, ideal for low and/or highly reflective ceiling
• Input Impedance: 4 Ohm nominal, 3.5 Ohm minimum in the bass range, 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: lower pair gold plated inputs, upper posts are non-polarized for 5  Treble Tilt steps (open, 3 different included power Resistors, add $200/pr for Cardas CPBP copper inputs (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)

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: demo speakers only in stock, no custom orders: Seller agrees to full refund minus all seller out of pocket fees.  Buyer agrees to have returned merchandise in shipping company hands within two weeks after receipt of merchandise.  Buyer agrees to 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.

END.