Three tweeters are used in a vertical array to approximate the midrange ribbon's line-source radiation pattern. The top two tweeters roll off at 8kHz, with the bottom tweeter run out past 20kHz. The rear tweeter is wired out of phase (…
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Although the II.5's tweeter looks at first glance like a conventional dome tweeter, the driver is a custom flat-ribbon type designed by Arnie Nudell. This tweeter, used throughout the Genesis line, has a 0.0001"-thick diaphragm on which a conductor has been etched. As with the midrange, the Genesis tweeter is more properly called a planar magnetic driver.
What's more, the II.5s didn't sound strained, congealed, or flat when pushed hard. Rather, they reproduced the most demanding passages with such ease that it seemed they weren't even being stretched. At no time did the II.5s show any sign of reaching their dynamic limits—even with such very challenging recordings as Pomp and Pipes (Reference RR-58CD) played back at high levels. These loudspeakers were made for full-scale orchestral music played loudly.
The wide dynamic window in which the music could express itself was greatly enhanced by the II.5's bass performance. Until you've heard…
The soundstage of the II.5 system was absolutely spectacular—wide, deep, layered, and transparent. In fact, when the II.5s were tweaked just right, and fed by topnotch source components and amplification, they produced the most spectacular soundstaging I've heard from a hi-fi system. The sense of a huge acoustic existing in space before me was so real that I found myself instantly accepting this artificial reality. Some loudspeakers make you work a little to believe their illusion of soundstaging; the II.5s compelled me to believe I had been transported to the original acoustic event. For…
Sidebar 1: Specifications
Description: Three-way floorstanding loudspeaker with woofer amplifier. Driver complement: Two servo-driven 12" woofers, one 4' ribbon midrange, four 1" planar tweeters. Impedance: 4 ohms. Sensitivity: 90dB/1W/1m. Frequency response: 20Hz–20kHz ±3dB.
Dimensions: 28½" W by 6' H by 2½" D. Weight: 1250 lbs/pair shipping, 1000 lbs/pair net.
Finish: Brazilian rosewood.
Serial numbers of speakers reviewed: 251006/7.
Woofer amplifier power output: 400W RMS/channel (into 2 ohm load presented by the II.5 woofers).
Amplifier dimensions: 19" W by 41/2" H by…
Sidebar 2: System
At the time of writing, I've been using II.5s for the past five months, auditioning them with a variety of equipment. Without question, the best amplifiers for the II.5s were the superb Audio Research VT150 tubed monoblocks (reviewed in Vol.17 No.8). When relieved of driving the woofers, the VT150s could really sing. It was almost as if these products were made for each other: the II.5s were particularly adept at resolving things the VT150s do so well—eg, depth, space, truth in timbre, and layering. After trying solid-state amplifiers, I recommend tubes for the II.5.…
Sidebar 3: Measurements
John Atkinson measured the II.5s in my new listening room—a much easier proposition, given the system's weight, than trucking it to the test lab in Santa Fe—and was therefore only able to perform a limited set of measurements. The II.5's impedance magnitude and phase angle are shown in fig.1. Note that this plot is of the midrange and tweeter section only—not the woofers. The minimum impedance is 3 ohms through the top octave, with a slightly higher 3.8 ohms or greater through the rest of the band. The combination of the phase-angle and the impedance magnitude in…
"What about coming over for a little bit of din-din?"
That's how my long, peculiar relationship with J. Gordon Holt began, back in 1978. Born on April 19, 1930, Gordon died Monday July 20, 2009 after a long struggle with emphysema. He leaves behind his son Charles and daughter Alicia, both featured in old issues of Stereophile, his great Colorado friends Bob O'Neill and Steven Stone, both former Stereophile contributors, and legions of grieving audiophiles. We are all struck down by his passing.
Gordon had moved to Santa Fe that year and was yearning for audiophile companionship (…
Letters
J. Gordon Holt
Editor: My father passed away July 20, shortly after noon Colorado time. He had suffered a long fight with COPD-emphysema, and he died in his home with his family around him. If you are so inclined, you can pay him your respects by having a good martini and complaining about the weather.—J. Charles Holt, Boulder, CO
Cheers, Gordon
Editor: To the man who discovered, defined, and truly verbalized audiophilia—cheers! Thank you, J. Gordon Holt, for the many years of enjoyment, and—oh, it's hot, humid, and sunny today—darn!
Be with God,…
Regina Spektor: Far
Sire 519396-2 (CD). 2009. Mike Elizondo, Jeff Lynne, Jacknife Lee, David Kahne, prods.; Adam Hawkins, Marc Mann, Steve Jay, Tom McFall, engs. AAD? TT: 47:21
Performance ****
Sonics ****½
Sire 519396-2 (CD). 2009. Mike Elizondo, Jeff Lynne, Jacknife Lee, David Kahne, prods.; Adam Hawkins, Marc Mann, Steve Jay, Tom McFall, engs. AAD? TT: 47:21
Performance ****
Sonics ****½
Sounding adorable and singing in a little-girl voice while aspiring to be taken seriously as a confident, capricious pop artist is a singular blend in the vast expanse of popular music, one that singer-pianist-songwriter Regina Spektor has nearly perfected on her third album, Far.
Nowhere is the range of Spektor's woman-child vision more apparent than in Far's best…
These days, it seems you can't shake a stick without hitting a USB DAC, but Ayre's QB-9 ($2500) is something a little different. Ayre's marketing manager, Steve Silberman, was adamant: "The QB-9 isn't a computer peripheral. It makes computers real high-end music sources."
The rules have changed today
What makes the QB-9 different? I'll just hit the high points here. (For the full particulars, see Ayre's white paper.)
To achieve the maximum resolution, a D/A converter must use a high-precision clock circuit running at a fixed frequency to control the timing of the…