KEF iQ9 loudspeaker
KEF's least expensive line, the iQ series, includes five two-channel models starting at $300/pair. (There are also iQ center and surround models.) I chose the top of the line, the iQ9, a floorstander retailing for $1200/pair. All Q speakers feature KEF's unusual Uni-Q coincident-driver array: a ¾" aluminum-dome tweeter placed at the center of a midrange cone. KEF claims that this array—derived from their more expensive Reference 203 and 205 models—results in broad dispersion of the mid- and high frequencies and eliminates narrowed dispersion, or "lobing," at the crossover frequencies.
The magnetically shielded, biwirable iQ9 uses a 6.5" titanium-coated polypropylene-cone midrange unit to cover the 280Hz–2.8kHz range. It also has two 6.5" low-frequency drivers, each in its own housing with its own front-loaded port, to minimize crosstalk. This use of two voice-coils and smaller drivers is intended to increase the iQ9's speed, articulation, and power handling, and the smaller woofers permit a narrower baffle, which in turn permits a smaller footprint—which, per KEF, improves the imaging. Finally, the vertical driver-port-driver-port array is intended to spread the bass-radiating area, thus minimizing the excitation of vertical room modes, according to KEF's chief of design, Dr. Andrew Watson.
I preferred listening to the iQ9s with their grilles off. This provided slightly more detail and transparency, as well as crisp, natural high frequencies.
I was immediately taken by the KEF iQ9's detailed, transparent, and colorless midrange, which had a natural, organic presentation of low-level dynamic inflections. All vocal recordings I listened to were impressive through the iQ9. The closely miked and extended range of Joni Mitchell's voice on "Urge for Going," from Hits (CD, Reprise 46326-2), is ruthless in uncovering a speaker's colorations, resonances, and midrange quirks. But through the KEF she sounded gorgeous, silky, and uncolored. I had a similar reaction to the voice of Madeleine Peyroux on "Hey Sweet Man," from Dreamland (CD, Atlantic 82946-2), though I found myself focusing more on dobro player Marc Ribot's delicate fingerpicking.
The iQ9's lower midrange was particularly breathtaking, and most noticeable in lower-register woodwind passages in well-recorded classical works, such as the bassoon passages in David Chesky's Violin Concerto (Area 31, SACD/CD, Chesky SACD288). Solo-piano recordings elicited similar reactions from me—Keith Jarrett's improvisations in Radiance (CD, ECM 1960/61) coaxed a warm, rich, woody tone from his Steinway; the piano's middle register sounded organic with linear dynamics. Radiance also highlighted the iQ9's impressive high frequencies, which, with all recordings, were extended, detailed, delicate, and uncolored.
I realized that to put the iQ9's tweeter through its paces, I needed to mine my orchestral vinyl. The violins on Pinchas Zukerman Plays and Conducts Vivaldi Concertos (LP, Columbia M32230) were open and airy. I was even more impressed with Charles Munch's reading, with the Boston Symphony, of Ravel's Daphis et Chloé (LP, RCA Living Stereo LSC 1893). The massed violins and cellos were naturally searing but sweet, and the upper partials of all flutes and piccolos were extended and uncolored. This "shaded dog" also revealed another strength of the iQ9: its ability to render a deep, wide soundstage with excellent specificity and convincing reproduction of ambience and hall sound.
With John Rutter's Requiem (LP, Reference RR57), the holographically represented members of the choir were layered across the deep soundstage, and I could easily discern the height of the church's ceiling. Similarly, on Antal Dorati and the London Symphony's recording of Stravinsky's The Firebird (LP, Mercury Living Presence 90226), I could unravel detail and follow each instrument quite easily, even during the most dense passages, and it was easy to hear the instruments reverberate off the rear wall of the recording space. I was particularly taken with the vibrant top-octave extension of the pizzicato string and xylophone passages.
Speaking of plucked strings, the iQ9 was an extraordinary reproducer of transients. Guitar fans should like the way all transients were lightning-fast and clean through the KEF, but with no trace of hardness. This would make the iQ9 a speaker for percussion fans as well. I dragged out my original UK pressing of King Crimson's Larks' Tongues in Aspic (LP, Island ILPD 9230) and marveled at the frantic interplay of percussionists Bill Bruford and Jamie Muir. This recording is full of low-level dynamic subtleties that are masked by all but the most revealing speakers. The iQ9 hid nothing.
As expected, the double woofer-port array could produce quite extended bass for a speaker of this size and price. The entrance of the bass drum in the Ravel recording was startling, lifelike, and room-shaking. Also on the plus side was the reproduction of electronic midbass energy. However, there was a midbass warmth that was problematic with some recordings. Even so, on Kraftwerk's recent live recording, Minimum/Maximum (CD, EMI 60611), as well as on Sade's Love Deluxe (CD, Epic EK 53178), the midbass emphasis of synth and drum machines added a sense of drama to the music that I found quite attractive.
The reproduction of bass instruments depended on the recording. Jerome Harris' bass on "The Mooche," from Editor's Choice (CD, Stereophile STPH016-2), was a touch warm but quite natural, although the kick drum seemed a bit thick on this recording through the KEFs. The double bass on George Crumb's Quest (CD, Bridge 9069) was naturally woody, but with a resonant quality that sounded overly round. The iQ9's midbass was most problematic with electric bass guitars that were mixed high in rock recordings. On Mighty Sam McClain's Give It Up to Love (CD, JVC JVCXR 0012-2), the emphasized, resonant, sluggish bass guitar sounded more like organ-pedal tones.
But the iQ9's high-level dynamic performance suggested a speaker of much larger size (again, presumably, the individually ported woofers helped). This made bombastic orchestral warhorses dramatic and captivating. Moreover, I could really party with this speaker. Playing the live Kraftwerk CD, I didn't hesitate to crank up the iQ9 to disco levels, which it produced without strain, coloration, or any trace of coagulation.
The NHT SB-3 had a rich, warm midrange, but was less detailed than the KEF iQ9, and its highs were less detailed and extended. The NHT's midbass was a bit more extended and was rather warm, but didn't have the KEF's midbass emphasis. Both speakers were dynamically impressive, the KEF more revealing of low-level dynamics, the NHT with more impressive high-level dynamic slam.
The Epos M5 had a detailed, neutral midrange that was as impressive as the KEF iQ9's. The iQ9 had a slightly more convincing and liquid lower midrange; the Epos was slightly drier in this region. The Epos's midbass was tighter and more natural, but the KEF's bass extension was better. The two speakers were equally impressive in terms of transient articulation, high-frequency extension, and detail.
The Amphion Helium2's natural midrange was even more detailed than the KEF iQ9's; the high frequencies were equally delicate, detailed, and extended through both speakers. The KEF's midbass was more natural, but the KEF also had more extended deep bass. Though I felt the Amphion's overall dynamic performance was even better than the KEF's, the iQ9's greater ease with loud, bombastic recordings was likely a result of its larger cabinet size and number of drivers.
The KEF iQ9 is, overall, an impressive performer for its size and price, with a wealth of strengths over a broad range of program material that suggests a much more expensive speaker. Whether or not its single shortcoming—that midbass emphasis—is a problem will depend on your associated equipment and taste in music.
I'm sorry I waited so long to listen to another KEF speaker—the iQ9 gave me many hours of musical pleasure. Well done.
Footnote 1: My reviews of the B&W 603S3 and the Wharfedale Diamond 9.1 appeared in the August and November 2005 issues, respectively. The final stop in this tour will be a review of the Monitor Audio Silver-RS6, scheduled to appear in the March issue.