Vinylphile Magazine : Equipment Reviews

MartinLogan • Spire Electrostatic Speaker

By Rich Teer | June 4th, 2010

When thinking about high-end audio equipment, certain manufacturers are almost synonymous with particular categories. For example: it’s hard not to think of Krell or Pass Labs when talking about high powered solid state amps, Audio Research or Conrad Johnson when talking about tube amps, and SME or VPI when talking about turntables and tonearms. MartinLogan is practically synonymous with electrostatic speakers (at least on this side of the Atlantic; one might argue that Quad enjoys a similar reputation in Europe, especially in its native Britain), having introduced the audio world to their curvilinear line- source (CLS) technology in the mid 1980s.

One of the problems with electrostatic speakers is that they usually require very large panels in order to reproduce bass frequencies, especially if the music’s dynamics are to be faithfully portrayed. Large panels can be harder to accommodate in a domestic setting, and are cumbersome to move around. Consequently, most of MartinLogan’s speakers are hybrids, with one or more dynamic cone woofers handling the bass frequencies while an electrostatic panel handles the mid-range and treble.

In 2008 MartinLogan introduced the CLX, the long-awaited full-range successor to the CLS. At about the same time, they announced the first hybrid to benefit from a trickle-down of the CLX’s technology, the Spire.

Technology

Measuring a relatively room-friendly 150 cm x 32 cm x 45.1 cm (59” x 12.5” x 17.75”), the Spire features a 112 cm (44”) CLS XStat electrostatic transducer, which handles the mid-range and treble frequencies above 320 Hz. The electrostatic transducer is housed within a rigid extruded aluminum and composite structure MartinLogan calls an AirFrame, and is comprised of three components: the Mylar-film diaphragm (whose back- and-forth pistonic motion creates the sound we hear), a pair of insulated stators between which the diaphragm is suspended, and a number of horizontal clear spars that stiffens the assembly across its width. The stators contain numerous holes through which the sound passes; MartinLogan claim that the latest version of the MicroPerf stators expose almost twice as much of the diaphragm’s surface area as an equally-sized traditional electrostatic panel, without compromising the AirFrame’s structural integrity. By exposing more of the diaphragm’s surface area, the efficiency and dynamics are said to be greatly improved.

Bass frequencies up to 320 Hz are handled by a single high excursion 25.4 cm (10”) aluminum-cone PoweredForce active woofer. The woofer is powered by a built in 200 W (into 4 Ohms) amplifier, and enclosed in a sealed, non-resonant asymmetrical chamber.

Perhaps the most significant technology to trickle down from the flagship CLX is the hand-built Vojtko crossover (named after its designer, Joe Vojtko), which features audiophile-grade polypropylene capacitors and air-core coils.

On the rear of the cabinet, the Spire features two pairs of three-way, gold-plated custom speaker terminals (to facilitate bi-wiring if desired), a toggle switch to select the intensity of the logo-shaped LED on the top of the enclosure (high, low, or off), a 35 Hz level control (±10 dB), and an IEC mains socket with power indicator LED. The Spire comes fitted with rubber feet which can be replaced at the user’s discretion by custom Energy Transfer Coupler (ETC) spikes. My listening room has a carpet-on-concrete floor, so once the review Spires had broken in I installed the ETC spikes, which resulted in a fuller, tighter bass.

Room Placement and Listening

The Spire, like all electrostatic speakers, has a dipolar radiation pattern, which means that as much sound energy comes out their back as their front. Consequently, the Spire needs plenty of room to breath, and should be placed fairly far away from walls (especially the front walls—those behind the speakers). After a bit of experimentation, I ended up placing the Spires as recommended in the “Extra Tweak” section of MartinLogan’s excellent user manual. The distance from the front wall (to the centre of the electrostatic driver) was about 147 cm (58”), and they were about 137 cm (54”) from the side walls. The distance between the two centre panels was about 221 cm (87”), and my listening position is about 350 cm (138”) from the speaker plane. Using ye olde flashlight trick (whereby one points an under-chin flashlight at the electrostatic panel and adjusts each speaker’s toe-in until the flashlight is reflected in the inner third of the panel), I thought that in my room a slight toe-out yielded the best imaging and treble quality.

Out of the box, the Spire sounded very veiled, as though a thick blanket had been thrown over them. The bass was wooly and ill-defined, and the treble was muffled. Fortunately, these issues quickly cleared up as the Spires broke in: the bass became fuller and richer, and the treble became more airy and clear. By the time I settled down for any serious critical listening, the Spires had been playing for well over 100 hours.

Two things immediately struck me when I listened to the broken-in Spires: their extended frequency range, and how clear they sounded. Most speakers I’ve listened to so far have at least some veiling, the degree of which ranges from almost as though the speaker has a carpet in front of it to as though the carpet had been replaced by a thin cotton sheet. I don’t hear that veiling with the Spires—they are very revealing about the quality of the signal being fed to them, but without sounding etched. Some speakers have a rising, emphasised treble that can lead some listeners to believe that they’re somehow more revealing or detailed, but I find listening to speakers with this false clarity to be very fatiguing. And listening to the Spires is anything but fatiguing: I’ve had many multi-hour listening sessions where I’ve listened to numerous records, without any sense of fatigue.

An example of the clarity I’m talking about is the sound of the cash registers at the beginning of Money, from Pink Floyd’s Dark Side of the Moon [EMI/Harvest LPCENT11], and the clock chimes from Time on the same LP. The Spires’ clarity and neutral tonal balance can lend a real “you are there” palpability to the right recordings. On Send in the Clowns [Jazz Planet JP 0779-12], I could’ve sworn that Bill Henderson was in my room. Or more precisely, I could’ve sworn that I was one of the patrons in the restaurant where the track was recorded. Henderson was right there, as was the piano and other patrons (in addition to their clapping, the latter were given away by the occasional glass quietly chinking, and other background sounds typical of a restaurant).

The Spire’s bass is fast, extended, deep, and tuneful, but—and this is a little but—perhaps lacking a bit of heft at the lowest frequencies (admittedly, I might be picking nits here). Some speakers smear the bass, making it hard to follow the bass line. Take, for example, the bass in Telegraph Road from Dire Straits’ third LP, Love Over Gold [Vertigo 25PP-60]. When the track gets busy as it builds up to the finale, the Spires let you hear the individual notes of John Illsley’s bass guitar, even though there are lots of other things going on.

Another track which shows off the Spires’ great tuneful bass is Way Down Deep from The Hunter by Jennifer Warnes [Cisco CLP 7063]. The bass guitar and especially the talking drum are exquisite, the Spires wonderfully portraying the latter’s deep “boing” sound. Gary Karr’s 1611 Amanti double bass on Adagio d’Albinoni [King Record KIJC 9125] has the right weight, without being over powering.

What I’ve just said about the bass applies to low to medium playback levels. But when the volume is really cranked up, the bass has a less visceral impact than real life. Played loudly enough, the bass drum thwacks in the opening track of Lt Kije [Classic Records LSC-2150] should be felt in your chest as well as heard, but at the end of the day, there’s only so much air a single 25.4 cm driver on each channel can move. I don’t want to make a too big a deal of this, though, because the Spire’s bass is generally very satisfying. Those who want to add more slam to the lower registers might want to consider augmenting the Spires with a pair of MartinLogan’s Descent i subwoofers (if space permits), or using the Spire’s bigger brother, the Summit X, which has two 25.4 cm bass drivers per channel.

Where the Spires really shine is their superbly neutral midrange. Free from the boxy colourations that plague most conventional dynamic speakers, the Spires reproduce sounds like female voices beautifully. The Spire reproduces delicate sounds like the shimmering of triangles, or the chiming of bells, with aplomb. On the right recordings, you can hear the air surrounding such instruments. And because the electrostatic driver is so lightweight, transients are also well reproduced.

Detail is another area where the Spires shine. I know it’s a bit of an audiophile cliché, but the Spires revealed to me numerous previously-unheard details in records I know intimately. A couple of examples that immediately come to mind are the triangle sweep near the beginning of the first epilogue of Jeff Wayne’s fantastic (and much under-appreciated on this side of the pond) The War of the Worlds [CBS 96000], and the various little sounds that appear throughout Jean-Michel Jarre’s second record, Equinoxe [Mobile Fidelity Sound Labs MFSL 1-227]. Subtle details that allow emotions to be communicated are well portrayed by the Spires. When we were listening to Linus and Lucy from The Vince Guaraldi Trio’s A Charlie Brown Christmas [Fantasy 8431], a friend of mine commented that you could really tell that Vince Guaraldi was really enjoying himself. On other speakers it sounded like he had just turned up for his day’s pay and gone though his set. What the lessor speakers were not reproducing was the feeling and subtle intonations the Spires reveal.

Imaging and sound staging are also great with the Spires. Given the right recording, not only is the sound stage wide, but it’s deep too. Take, for example, the breaking glass in Private Investigations from the previously-mentioned Love Over Gold. You can hear it just left of centre, but wayyyy back. The layering of orchestras is also well portrayed, with the percussion clearly behind the strings, woodwinds, and brass. On electronic music like Equinoxe, the Spires make it easy to pinpoint where various sounds are coming from, and easy to follow around the three-dimensional aural landscapes Jarre creates. One thing is for sure: properly set up, the width and depth of the sound stage created by the Spires is not limited to the listening room’s boundaries.

Verdict

Let me get straight to the point: the MartinLogan Spire is one of the finest sounding less-than-stratospherically-priced speakers I have had the pleasure of auditioning. Minor quibbles about the weight of the low bass aside, the Spire’s top-to-bottom coherency, tuneful bass, sparkling highs, and excellent imaging make it a real winner. If you’re shopping for a speaker at the $10,000 or so price point—and you have the space required for them to perform at their best—the Spire should be on your “must audition” short list. Very highly recommended, I put my money where my mouth is and bought a pair.

Specifications

Description Electrostatic/cone hybrid loudspeaker.
High-frequency transducer 112 cm (44”) CLS (curvilinear line source) XStat electrostatic.
Low-frequency transducer 25.4 cm (10”) high-excursion aluminum cone woofer.
Crossover frequency 320 Hz.
Frequency response 29-23,000 Hz ±3 dB.
Sensitivity 91 db/2.83 V/1 m.
Nominal impedance 4 Ohms (0.8 Ohms at 20 kHz).
Power handling 250 W.
Dimensions (hwd) 150 cm x 32 cm x 45.1 cm (59” x 12.5” x 17.75”).
Weight 26.3 kg (58 lbs) per channel.
Finishes Natural cherry, dark cherry, black ash, or maple veneer (other finishes available to order).
Serial numbers of units reviewed SPTL 008 and 009.
Price $8,495 per pair.
Warranty 5 years non-transferable.

Manufacturer

MartinLogan
2101 Delaware
Lawrence, KS 66046
USA
(785) 749-0133
www.martinlogan.com

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