Stand Loudspeaker Reviews

Understanding field coils
"Field-coil drive units—in laymen's terms, powered drive units, which use an electromagnet to generate the magnetic field with which the voice coil interacts (by Lorentz Force)—date from the earliest days of electrical music reproduction." That is from the Audio Note website. "Not long after the turn of the 20th century, permanent-magnet technology was not sufficiently advanced to make a conveniently sized, and priced, speaker drive unit."

Field coils reportedly offer a calmer, more relaxed and graceful sound, delivering more information and improved tonality. Some would say they are faster and more linear than speakers that use conventional magnets. Field-coil speakers are still relatively rare, but their numbers are increasing.

"Faster, in the hi-fi case, is usually a subjective term, and a vague one at that," Grove told me. "Actual acceleration of the driver is related to the gap flux and cone weight, etc. To all intents and purposes, these would be the same regardless of magnet type if those parameters were held equal. However, the AN-E/SPx Ltd. does have a higher gap flux than either the ceramic or alnico versions. This was tuned by ear to optimize bass quality with our amps.

"A way to think of it is that permanent magnets are like a stretched elastic band, with the speaker voice coil trying to move against it," he wrote. "No matter how much energy is stored in that elastic band—and there is a limit to how much; otherwise, the physics of bass tunings won't work anymore—it will move in response. The field coil doesn't have that limitation. Energy can be applied to compensate, and it works by simple transformer action. The permanent-magnet system is a closed system; the field coil is not."

Setup
Audio Note UK provided a pair of 10" high, black powder-coated steel speaker stands. I began my audition using a pair of Anthony Abbate/Box Furniture stands, which are made of wood. The metal stands, though heavy and unwieldy to set up, proved essential in getting the best sound.

Initially running a single pair of AudioQuest William Tell Zero speaker cables to the AN-E/SPx Ltd. with its dual sets of binding posts joined via a jumper, I experimented with biwiring the speakers, which, like the metal stands, also proved essential. The difference was not subtle. Using the AudioQuest cables on the tweeters and ArgentPur 12 or Danacable Sapphire Reference Mk.2 cables to the woofers, the sound sprung to life, with excellent separation, soundstaging, coherency, and focus. The ArgentPur cables provided more sweetness and air, the Danacable Sapphire more presence and girth. I don't know if this is true with all Audio Note speakers, but I didn't really hear their exceptional abilities until biwiring was employed.

"The ported enclosure of the AN-E/SPx Ltd. has been designed to be placed close to room boundaries, where the bass performance is augmented significantly by the additional reinforcement from the nearby walls," noted the manual. I obeyed. The speakers ended up 10" from my back wall, 73" apart from the tweeter domes, and 108" from my listening seat.

Listening
I wanted to evaluate the speaker with a wide array of music, so I pulled out CDs and vinyl by Pat Metheny, Steely Dan, The Beatles, Kraftwerk, The Doobie Brothers, Dave Holland, Miles Davis, Air, the Great Jazz Trio, various classical discs, and Aphex Twin.

The AN-E/SPx Ltd.'s impact on digital listening with CDs was immediately and profoundly evident in its bass reproduction.

The speaker's ability to render bass weight was nothing short of spectacular, transforming mere listening into a visceral immersion. Specifically, with Pat Metheny Group's Speaking of Now (Warner Bros. Records 9 48025-2), the speaker's bass performance was so intense it bordered on overwhelming. It evoked the sensation of being plunged into the ocean's deepest depths, space filled by voluminous and profound bass. While this CD showcases an exceptional, almost anomalous bass presence, the AN-E/SPx Ltd. consistently demonstrated its ability to deliver deep, well-defined, extended bass with solid tonal accuracy, faithfully reproducing the information contained within the recording. The AN-E/SPx Ltd. proved capable of delivering bass impact of all shades.

Despite the inherent subjectivity of "speed," the AN-E/SPx Ltd. delivered a consistent sense of swiftness, clarity, and transient articulation—among the best I've heard. Music unfolded with remarkable energy and lucidity. Familiar recordings were revitalized, eliciting visceral excitement and emotional resonance. Perhaps because of the field coil's ability to minimize noise, I heard extraordinary resolution—superb clarity—but also richness, detail, all within a sonic whole. One evening, upon taking center seat and imbibing a good Beaujolais, Alex Halberstadt, who was visiting, remarked, "This is the richest, most refined version of your system I've ever heard."

Record after record, music played with incisive coherency and refined presence. I found the presentation impossible to fault. Somehow, the speakers clearly revealed the sound of upstream components and cables—that's the resolution I suppose—while retaining a consistent sense of refined musicality. Transparent but with their own character. They played ZZ Top's "Waitin' for the Bus"/"Jesus Just Left Chicago," from Tres Hombres (London Records XPS 631), with all the power, gravity, connection, and brisk winter-morning clarity I could desire.

Regarding sonic stealth: The AN-E/SPx Ltd. disappeared sonically as completely as any speaker I've reviewed. The Leslie-affected, chocolate-toned Rhodes piano signature of The Doobie Brothers' "Minute by Minute," from the album of the same name (Warner Bros. Records BSK 3193), was balanced by the musty, sinewy, whisky-flavored voice of Michael McDonald. I'd not listened to this record, with beautifully aromatic production by Ted Templeman and engineer Donn Landee, in years. The Audio Notes also exposed the song's string-synth overlays, which I'd never noticed before.

These AN-Es got to the meat of The Beatles' "I Saw Her Standing There" from Please Please Me (Parlophone PMC 1202). The driving riot of sound jumped, quaked, and startled in the clear, large acoustic of Abbey Road Studio Two, with particular focus on the resonant, raw tone of Paul McCartney's Hofner bass. If you want excitement, the AN-E/SPx Ltd. provides it.

The experience offered by the AN-E/SPx Ltd. was consistently intimate, resonant, and personal, as though the speaker was revealing the core of the recording. It unearthed music's emotional depth, revealing layers of meaning previously obscured. Each recording was revitalized, with the speakers amplifying the beauty of well-produced tracks while maintaining the integrity of less polished ones.

Even recordings marred by technical limitations were granted a renewed focus. Consider The Allman Brothers Band's 1969 debut (ATCO Records SD 33-308), captured at the famously noisy Atlantic Studios in New York City. This recording is notoriously murky and raw, yet the performance is special. Through the AN-E/SPx Ltd., the band's haunting power and southern gothic artistry were vividly conveyed. The recording's imperfections were not glossed over but, rather, presented as part of its character. The speaker acted as a conduit, faithfully transmitting essence, both brilliance and flaws, with unwavering, colorful honesty.

At times I felt at one with the musicians in the recording studio. Dave Holland's Triplicate (ECM Records ECM 1373), with its crazily panned stereo drums and gargantuan upright bass, never sounded so flat yet so rich and somehow orderly. The ominous rising tide of musicians at the beginning of Stravinsky's The Firebird, performed by the London Symphony Orchestra conducted by Antal Dorati (Mercury Living Presence SR90226), seemed malevolent, dynamic, and spookily intimate. The speaker's low noisefloor, created, I presume, by its field coil's swiftness, unmasked every corner of the recording in surprising ways.

The Miles Davis Quintet's Workin' with the Miles Davis Quintet, played from my original pressing (Prestige PRLP 7166), produced more revelations. While competent speakers render the recording's mood and dynamics, very refined systems capture the fine variations in "Philly" Joe Jones's cymbal work. The Audio Notes, with their resolution and wholeness, revealed the full spectrum of resonance and the percussive clarity of his sticks, exposing nuanced tonal distinctions among his cymbals as he transitioned through the solos of Davis and Coltrane.

Conclusion
The AN-E/SPx Ltd. Field Coil transcends technical analysis, offering a "meat and blood" immediacy that captured the very essence of every record I wanted to hear. Its integration of deep bass, clean midrange, and silken treble created a unified, emotionally resonant whole. This is music playback of extraordinary beauty, a near-supernatural experience that left me dumbstruck and humbled.