Soon after my review of the 107, KEF introduced its Uni-Q driver: a tweeter powered by a powerful but tiny neodymium magnet that enables it to perch on the front of the midrange unit's pole-piece, the midrange cone…
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The very last review I wrote for Hi-Fi News & Record Review (these days just plain Hi-Fi News)—before crossing the Atlantic to take up the reins at Stereophile in May 1986—was of KEF's then-new flagship speaker, the Reference 107. That rave review appeared in the English magazine's July 1986 issue, and was followed by equally positive reports from Stereophile's writers.
Sonics
Setup was straightforward, the 207s working at their best when toed-in to the 10'-distant listening seat and positioned a few inches farther out in the room than the Canton Karat Reference 2 DCs—the front of the Uni-Q pods were 40" (left) and 64" (right) from the side walls and 58" from the wall behind them. With the speaker standing on its feet, the supertweeter is a high 50" from the floor, meaning that unless a tall listener sits in a director's chair, his ears will be well below the supertweeter's axis and therefore not receive much ultrasonic energy. The Uni-Q tweeter is 45…
Setup was straightforward, the 207s working at their best when toed-in to the 10'-distant listening seat and positioned a few inches farther out in the room than the Canton Karat Reference 2 DCs—the front of the Uni-Q pods were 40" (left) and 64" (right) from the side walls and 58" from the wall behind them. With the speaker standing on its feet, the supertweeter is a high 50" from the floor, meaning that unless a tall listener sits in a director's chair, his ears will be well below the supertweeter's axis and therefore not receive much ultrasonic energy. The Uni-Q tweeter is 45…
On recordings that themselves sound hard, such as the DVD-A of Yes's Magnification (Rhino R9 78250), the KEF was unforgiving. (Both this album and Tutu have rather gritty-sounding highs—is this due to a heavy hand on the watermarking knob?) Anne-Sophie Mutter's Brahms Violin Sonatas (EMI CDC 7 49299 2, CD) sounded definitely "scratchy," the violin jumping forward out of the soundstage on some high-treble notes but not on others. However, comparing this 1983 recording with Arturo Delmoni's superb-sounding but more cautious 1996 performance of Sonata 1 (John Marks JMR 2), which was also miked…
Sidebar 1: Specifications
Description: Five-way, reflex-loaded, magnetically shielded, floorstanding loudspeaker. Drive-units: 0.75" (19mm) titanium-dome supertweeter; coincident (Uni-Q) 1" (25mm) titanium-dome tweeter and 6.5" (165mm) polypropylene copolymer-cone upper-midrange unit; 10" (250mm) paper-cone lower-midrange unit; two 10" (250mm) fiber-reinforced paper-cone woofers. Crossover frequencies: 120Hz, 400Hz, 2.7kHz, and 15kHz, 24dB/octave acoustic slopes. Frequency response: 40Hz-55kHz, ±3dB, 15 degrees horizontally off-axis. Sensitivity: 91dB/2.83V/m. Nominal impedance: 8 ohms (…
Sidebar 2: Systematics
Analog source: Linn Sondek LP12/Cirkus/Trampolin/Lingo/Ekos/Arkiv LP player on a Sound Organisation table.
Digital sources: Mark Levinson No.31.5 CD transport; Mark Levinson No.30.6 D/A processor; dCS 972 upsampler; Accuphase DP-85 SACD player; Technics DVD-A10 DVD-Audio player; Musical Fidelity Nu-Vista 3D CD player; Ayre D-1x DVD-V player.
Preamplification: Linn Linto phono preamp, Mark Levinson No.380S line preamp, Z-Systems rdp-1 digital control center (updated to handle 96kHz sources).
Power amplifiers: Mark Levinson No.33H monoblocks.
Cables:…
Sidebar 3: Measurements
Two practical problems hindered my acoustic measurements of the KEF Reference 207. The first is common to large speakers in that their bulk makes it difficult to lift them off the ground. The need to window out the inevitable early reflection of the speaker's sound from the floor restricts the midrange resolution of the FFT-derived graphs. The second was specific to this review in that the air temperature on the day I measured the KEF was just 40 degrees F. (Quasi-anechoic measurements require a large room, so I perform them outdoors to eliminate boundary…
Following the introduction of their very expensive, tube/FET hybrid SP11 preamplifier, there were rumors that Audio Research was working on a hybrid tube/transistor preamplifier targeted to cost less than $2000. The rumors were confirmed when ARC showed a black-and-white photo of the SP9 at the 1987 Winter CES. Obviously, like all magazines, we were impatient to receive a review sample, but the first review of the SP9 actually appeared in the summer '87 issue of Peter Moncrieff's IAR Hotline. Peter's review was almost intemperately enthusiastic, comparing the SP9 positively with early…
Sound Quality
On first listen, using high-level sources only, I am saddened to report that the sound was not good. In fact, it was hard, rough, thin, and both spatially and dynamically compressed. The phono preamp added more of the same of everything. The adjectives I used above—and I gave considerable thought to their choice—do not reflect merely personal value judgments on my part, but are descriptive of the changes wrought by the SP9 on signals passing through it. That is, they were audible on simple bypass tests, in which the preamp under test is compared with the signal being fed…
On first listen, using high-level sources only, I am saddened to report that the sound was not good. In fact, it was hard, rough, thin, and both spatially and dynamically compressed. The phono preamp added more of the same of everything. The adjectives I used above—and I gave considerable thought to their choice—do not reflect merely personal value judgments on my part, but are descriptive of the changes wrought by the SP9 on signals passing through it. That is, they were audible on simple bypass tests, in which the preamp under test is compared with the signal being fed…
John Atkinson added a few words in November 1987 (Vol.10 No.8):
Worried by JGH's findings on the sound of the SP9, I borrowed the unit from him and installed it in my own system, letting it warm up for a total of five days before attempting any listening. It was used first as a conventional preamplifier, taking the output of Linn Troika and Koetsu Red MC cartridges and feeding my Krell KSA-50 power amplifier (which has an input impedance a bit on the low side at 20k ohms), first via 3m of Monster Interlink Reference (total capacitance 450pF), then via 5m of Radio Shack 300 ohm aerial…
Postscript: Blind Listening (from November 1987, Vol.10 No.8):
JGH having written the review and JA having prepared it for typesetting, the two then set off for England to visit London's Heathrow Penta hi-fi show, organized by Hi-Fi News & Record Review magazine (full report next month). In the meantime, however, as is Stereophile's practice, a copy of the edited review was sent to the manufacturer so that they could submit a comment to appear in the same issue of the magazine. As you can see from Terry Dorn's letter on p.184, Audio Research was both a little hurt and puzzled by the…