Bookshelf Speaker Reviews

Tweeter is the name of a speaker driver, an audio retail chain, and a Warner Brothers cartoon character. No, wait, that would be Tweety Bird. However whimsical the name may sound, the tweeter plays a crucial role in speaker design. An average one delivers not only high frequencies, as the chirpy name suggests, but also a significant share of the upper midrange. It's possible to design a loudspeaker without a tweeter. But most speakers depend on their tweeters to deliver harmonics, detail, airiness, and all frequencies above the crossover to the lower drivers.

If one tweeter is good, would two be even better? DALI says yes with the IKON line, citing several advantages. They claim wide dispersion, to deliver the same performance to every seat in the house, and uniform impedance, so the load presented to the amplifier remains the same at all frequencies. In fewer words, DALI strives for evenness and consistency. These are good things.

The system under review here uses three IKON 2 stand-mount speakers for the front left, right, and center channels and two IKON On-Walls for the surrounds—along with the IKON Sub. DALI recommends these speakers for smaller rooms. The line also features three floorstanding models, the IKON 5, IKON 6, and IKON 7; the IKON Vokal 1 and Vokal 2, both centers; and the IKON Phantom, an in-wall model.

Please note that I opted, as I sometimes do, to eliminate the horizontal center-channel speaker and use three identical bookshelf-size speakers across the front three channels for the most seamless imaging. The IKON 2 is packaged in pairs. Whether you'll be allowed to buy, say, three or five of them is at the dealer's discretion. The review system's total price for three IKON 2s, two On-Walls, and one Sub is $3,865.

Aluminum and Silk
The IKON 2 and IKON On-Wall have identical drivers. A rectangular, polymer-coated aluminum ribbon tweeter and a dome-shaped silk textile tweeter handle the high frequencies. The ribbon is driven by conductors etched into its surface, which functions as a voice coil. The dome tweeter handles both upper-mid and high frequencies, starting at 3.2 kilohertz and rolling off naturally above 14 kHz; the ribbon tweeter handles only extremely high frequencies, from 14 to 30-plus kHz, effectively functioning as a super-tweeter. A similar dual-tweeter array appears in DALI's pricier Euphonia and Helicon lines.

In addition to handling different high-frequency ranges, the dual tweeters also behave differently in the way they disperse sound around the room. The ribbon tweeter has a broad, horizontal dispersion pattern that evenly covers various seating positions, while the dome tweeter has a tendency to beam at the sweet spot progressively more and more as the frequency increases.

The woofers are a composite of cellulose fibers. Cellulose fibers are light, stiff, easily driven into motion, distribute energy in random directions, and prevent resonance buildup. DALI designs the drivers but sources them from other manufacturers.

Unlike the Euphonia and Helicon speakers, which have rounded enclosures, the IKONs live in more conventional hard-edged boxes. While their vinyl-wrapped exteriors are nothing to write home about, DALI took special pains with their interiors.

To control resonances, the IKON uses dual layers of medium-density fiberboard that are bonded and damped with adhesive. The drivers are built into separate chambers to minimize interaction between the tweeters and the woofer. The crossover circuitry is hand-wired, distributed over two boards, and mounted directly to the speaker terminals. The gold-plated binding posts are covered in hard transparent plastic, giving them a jewel-like appearance. They are the most beautiful binding posts I've ever seen. (I may need to re-examine my concept of beauty.)

My reference receiver for this review, as always, was the Rotel RSX-1065, the five-channel equivalent of the newer RSX-1067. The main signal source was an Integra DPS-10.5 universal disc player. Speaker cables were Monster M1.4s (biwire) and M1.2s (non-biwire); and I used interconnects from www.BetterCables.com.

Secret Handshakes and Mad Experiments
The IKONs' dual-tweeter array did a great job of dispersing high frequencies around the room. When I moved off-axis, the image suffered a very slight thinning in the midrange but retained its treble outline. Overall, the midrange and treble presentation was on the forward side of neutral.

While this occasionally prompted me to lower the volume, it also accented some characteristics of familiar test tracks in appealing ways. For instance, in "Wild Country" from Chris Whitley's Dirt Floor—a test track I've used consistently for a decade—the singer's reedy voice came off a bit steely. However, the left-to-right imaging was stronger than usual, with the voice precisely fixed between the center and left speakers and the acoustic steel guitar between center and right. The IKONs entirely transcended the ambient murkiness that some speakers exhibit with this recording. Perhaps the ribbon microphone used to record the album and the ribbon tweeters in the speakers were doing some kind of secret handshake?

Another effect that turned my head was the cymbal sound in Live at Leeds by the Who. For a moment, I wondered if I'd been listening to this record for 30 years and somehow missed the use of a flanger on the cymbals. Then I realized that the subtle phase shifts I was hearing came from the rocking of the cymbal stands in front of the mikes as Keith Moon gave them his customary walloping. Any speaker that uncovers new surprises in this kind of familiar stuff is good for endless hours of entertainment.

In a mood for reductionist comparisons, I decided to block the tweeters and evaluate each one independently. I cut strips of paper and attached them to the baffles with masking tape, taking care not to let the adhesive touch the drivers. With the ribbon super-tweeters blocked and only the silk domes operating, the speakers produced a fully satisfying treble and midrange. This wasn't a surprise, because the domes don't start to roll off until 14 kHz, covering the upper mid-

range and just about all the highs audible to most adults of a certain age. Had DALI deliberately designed the speakers to operate this way, I still would have given them a strong, positive review.

With the domes blocked and only the ribbon tweeters operating, the speakers took on a bright and ringy sound with a noticeable gap between the midrange and treble. Of course, that's not the way they were meant to work, and this was a mad experiment to begin with.

I also bypassed the subwoofer and listened to the IKONs running full range. The IKON 2 confidently covered the entire male vocal range, while the IKON On-Wall tended to underplay deep-in-the-chest bottom notes (a forgivable trait in a surround speaker). Drum kits were fairly complete with the IKON 2, less so with the On-Wall. The sub reinforced the bass drum, of course, but it always does.

Stereo Variations
To challenge the tonal and spatial smarts of the IKONs' mixed tweeters, I turned to Variations, Robert Silverman's performance of Beethoven's Diabelli Variations. The Stereophile recording uses the IsoMike technique that Ray Kimber of Kimber Kable pioneered. IsoMike combines a heart-shaped baffle—actually, in this case, several heart- and egg-shaped baffles—with a single pair of omnidirectional mikes. The aim is to optimize imaging and tone color at the same time, which is normally a tough tradeoff. To hear this unusual CD as the artist and engineers intended, I cut the system down to two channels, ran both of them full range, and silenced the center, surrounds, and sub.

This produced a stereo image that was full but not vague. The piano had a close-miked feel with a sharp attack and a controlled decay that always seemed as if it came directly from the piano, not from the concert hall. I felt as though I were the pianist himself, not a member of the audience. This was not a decorous, ceremonial Beethoven but a lively, in-your-face Beethoven. Find out more about the recording technique at www.kimber.com/isomike. The CD is sold through www.stereophile.com.

The next two auditions thawed the sometimes icy presentation, giving the speakers a chance to toss out a mellow midrange. David Russell knowledgeably explores the classical repertory of Spain and South America in Art of the Guitar. Telarc's multichannel SACD gave the instrument a warm tone and an ambience that sweetened each note and extended the decay. Only a faint reverb found its way into the center channel, granting the soundfield a diffuse feel.

Original producer Glyn Johns remixed Eric Clapton's Slowhand in surround for SACD. Clapton's voice was present in all three front channels, but only the left and right channel conveyed the main guitar parts. Secondary guitar and keyboard parts filled out the surrounds, completing a busy soundfield with little need for reverb. The IKONs delivered a warmth redolent of 1970s vinyl, as well as a full but tight drum sound.

Vast Multiples
Curse of the Golden Flower complements a story of ancient Chinese palace intrigue with a soundtrack rich in music and effects. The assumption is always that anything worth doing is worth doing in vast multiples, whether it's the footsteps of armies, the thundering of horse hooves, the clanging of swords, the whooshing of arrows—you get the idea. All this complex activity offered the ribbon and dome tweeters a chance to deliver an abundance of high-frequency information. The woofers were pretty busy, too, especially when drum reverb panned from the front channels to the surrounds. If the overall effect was sometimes clinical, it was never fatiguing. Perhaps the best moment occurred early in the movie, when hundreds of wooden percussion instruments tapped out a wake-up call that recalled the flying-bean scene in House of Flying Daggers.

Music and Lyrics required the IKONs to surmount a unique vocal challenge—delivering the singing voices of Hugh Grant and Drew Barrymore. They both earn points for trying in this otherwise predictable romantic comedy. Satirical treatments of 1980s synth-pop boy wonders and 21st-century hip-hop divas were spot-on. But the main event was Grant's George Michael impersonation, memorable both for the swiveling hips and the ironic grimaces carved deep into his face.

The Kovak Box is a Spanish-made thriller with a classic orchestral score. Composer Roque Baos evoked the classic music that Bernard Herrmann wrote for Alfred Hitchcock, especially Vertigo, with familiar melodic fragments and arrangements. The dual tweeters—especially, I think, the silk dome—brought out the string orchestra's sensuality, especially the sighing cellos that grace the opening frames, giving the low-budget production a big-budget sheen. This sci-fi thriller needed all the help it could get.

The DALI IKON system delivers true high-end sound with a high-end Danish accent. The speakers are worthy of top-notch surround separates; however, if you're not ready for a pricey preamp/ processor and multichannel amp, they also run well with top-of-the-line receivers (like mine). The mid four figures is not too steep a price to pay for this level of transparency, so long as their lean balance appeals to you. Your ears will thank you for auditioning these great-sounding speakers.

Highlights
• Dual tweeters team up to provide comprehensive highs
• On-walls offer simple solution for surround speaker placement
• Danish accent