Reviewer: Marja & Henk
Financial Interests: click here
Sources: PS Audio PWT; Dr. Feickert Blackbird MKII/DFA 1o5/Zu DL-103; Phasure XX-PC and NOS1 DAC;
Streaming sources: XXHighEnd; iTunes; Devialet AIR; La Rosita Beta; Qobuz Desktop
Preamp/integrated/power: Audio Note Meishu with WE 300B (or AVVT, JJ, KR Audio 300B output tubes); dual Devialet D-Premier; Hypex Ncore 1200 based monoblocks; Trafomatic Kaivalya; Trafomatic Reference One; Trafomatic Reference Phono One; Music First Passive Magnetic;
Speakers: Avantgarde Acoustic Duo Omega; Arcadian Audio Pnoe; Podium Sound One; Sounddeco Alpha F3; Soltanus Virtuoso ESL [in for review]
Cables: complete loom of ASI LiveLine cables; full loom of Crystal Cable cables; full loom of Nanotec Golden Strada; Audiomica Pearl Consequence interconnect; Audiomica Pebble Consequence
Power line conditioning: PS Audio Powerplant Premier; PS Audio Humbuster III; IsoTek Evo 3 Syncro; AudioMica Allbit Consequence
Equipment racks: Solid Tech and ASI amplifier and TT shelf
Indispensable accessories: Furutech DeMag; ClearAudio Double Matrix; Franc Audio Ceramic Disc Classic; Shakti Stones; Akiko Audio sticks; Kemp polarity checker
Online Music purveyors: qobuz.com, bandcamp.com, amazon.co.uk  
Room treatment: Acoustic System International resonators, sugar cubes, diffusers
Room size: ca. 14.50 x 7.50m with a ceiling height of 3.50m, brick walls, wooden flooring upstairs, ca 7 x 5m with a ceiling height of 3.50m, brick walls and concrete floor downstairs.
Price of review item:  $10'995/pr in US and Canada (introductory price) / €9'500 in Europe

Loudspeakerlandia can be divided into two major continents. On one thrives the dynamic driver, on the other hides the planar transducer. The dynamic driver is most populous by far. Due to its vast dynamic range, high power handling and sensitivity plus quite simple design and concomitantly lower manufacturing costs, almost 99% of all loudspeakers use cones ‘n’ domes. Flaws in a driver’s frequency response are relatively easily compensated for by limiting its bandwidth and commissioning other drivers designed specifically for a certain range; woofers, midranges and tweeters. Together with a filter system called the crossover, an array of drivers packed into a loudspeaker acts as one and in many cases it will still be considered a quasi point source.


Next to acting thus, dynamic drivers all share another feature - a voice coil. Electric current from the amplifier is sent through it. Being suspended inside a magnetic field created by two permanent magnets whose lines of flux cross the gap between them, the voice coil floats in said gap. Physics dictate that the current flow through the circular coil in the flux field causes magnetic forces to operate along the coil’s axis: the coil moves forward and back. Attached to the coil—in fact to the so-called former on which the coil is wound—is a cone or dome generally called a diaphragm. The faster the current alters in the coil, the faster the diaphragm will move the air it pushes against and the higher the frequency of the air movements will be. Those air movements are detected by our ear-brain system to translate as sound. Some sounds are even discerned as, yes music by our cognitive mechanism.

By contrast, planar loudspeakers do not use coils floating in a magnetic field. In a ribbon loudspeaker, a strip of aluminium is suspended between two strong permanent magnets. The music as current is sent though the ribbon which creates a magnetic field around it. This field interacts with the field created by the two permanent magnets and makes the ribbon move back and forth. The ribbon can be small for high frequency use or large for lower frequencies. Just like with dynamic drivers, a ribbon-based planar loudspeaker excites the air which we (can) process in our heads into music.


Another form of the planar loudspeaker is the electrostat. Compared to the electromagnetic principles of dynamic and ribbon drivers, the electrostatic driver is a completely different animal. It’s perhaps best to regard this type as one giant capacitor. An ultra-thin stretched membrane is attached between two rigid plates called stators. A very high voltage applied to the membrane often reaches 10kV. Once the audio signal is sent to the stators—the positive phase to one, the negative phase to the other—the signal creates an electrostatic field in relation to the incoming musical signal. That varying field now interacts with the static field of the membrane and makes the membrane move back and forth as it gets attracted and repelled by the stators. In moving this way, the air around the membrane is excited once again.


The stators are perforated to avoid obstructions to the air flow. An electrostatic loudspeakers or ESL needs power from the grid to work. For the static part of an ESL aka its membrane, the polarizing voltage must be generated and the incoming musical signal stepped up from a few tens of volts to several thousands. The biggest difference with any other type of loudspeaker driver is that there is no physical contact with the moving ESL diaphragm. Only electrostatic forces make the ultra-thin film move. That film is lighter even than the air it moves. Being so thin, a dozen micron (12 x 10-6 meter) or less, also makes the diaphragm free of energy storage or self resonance. Colouration is no issue. Whilst we are at the benefits of ESLs, here are some more before we'll get to the liabilities (you didn’t think this was a free lunch, did you?).