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I returned my attention to speaker placement, paying careful attention to the changes, both measured and heard, as I went along. More than anything else, I noticed that small shifts in loudspeaker and microphone position yielded greater measured differences than I'd expected—although the octave between 125Hz and 250Hz was consistently elevated by at least 3dB relative to the rest of the midband, which may have accounted for the dark quality. It was easy to get flat bass response all the way down to 25Hz, although not so easy to do it without bringing a 6dB peak at 31.5Hz along for the ride. I…
Sidebar 1: Specifications
Description: Three-way, reflex-loaded, floorstanding loudspeaker. Drive-units: 1" titanium-dome SuperTweeter, 1.25" aluminum-dome tweeter, 12" pulp-cone woofer (latter two drivers in coaxial configuration). Crossover frequencies: 1.1kHz, 12kHz. Frequency range: 30Hz-54kHz. Impedance: 6 ohms nominal. Sensitivity: 92dB/W/m.
Dimensions: 47.6" H by 17.3" W by 17.3" D. Weight: 108 lbs each.
Serial number of units reviewed: 029014M (both).
Price: $8350/pair. Approximate number of US dealers: 20.
Manufacturer: Tannoy Ltd., Home Audio Division, Coatbridge,…
Sidebar 2: Associated Equipment
Analog sources: Linn LP-12 turntable with Naim Armageddon power supply and Naim Aro tonearm; Rega Planar 3 turntable with Rega RB-300 tonearm; ZYX Airy S, Lyra Helikon Mono, and Dynavector DV10x5 phono cartridges.
Digital source: Sony SCD-777ES SACD player.
Preamplifiers: Audio Note M3, Naim NAC32-5.
Power amplifiers: Audio Note Kit One (300B), Fi 2A3 Stereo, and Naim NAP110.
Loudspeakers: Quad ESL-989s and Lowther PM2As in modified Medallion horns.
Cables: Nordost Valhalla, Nordost Valkyrja, Naim SNAIC (various), and homemade interconnects;…
Sidebar 3: Measurements
Though the big Tannoy's voltage sensitivity was slightly lower than specified, at 90dB(B)/2.83V/m, this is still usefully higher than average. The impedance remains above 8 ohms for most of the audioband (fig.1), but drops to 2 ohms in the region covered by the SuperTweeter. In addition, the rather extreme electrical phase angle in the mid-treble—note the combination of 4.2 ohms and -51.8 degrees at 7.5kHz—will demand current from the partnering amplifier. Although there is generally not much musical energy above 5kHz, a good design rated at 4 ohms will still work…
Mirage /ma-'räzh/ n [F, fr mirer to look at. fr. L mirari] 1: an optical effect that is sometimes seen at sea, in the desert, or over a hot pavement, that may have the appearance of a pool of water or a mirror... 2: something illusory and unattainable, like a mirage.
During our long wait for the now well-known Mirage M-1, this latter definition seemed the more apt. Its journey started in June of 1987, when I made a special trip up to the Audio Products International suite after that year's Chicago CES had closed down. All the Canadian worthies from API were sitting back after a…
All dipoles have traditionally shared many features, as well as most of their disadvantages. Dipoles typically consist of light sheetlike diaphragms driven more-or-less over their entire area, which gives them big advantages in transparency, "quickness," coherence, and lack of mechanical energy storage (compared to conventional cone drivers). This last advantage is a big one, which is what I think most people describe as "speed" in the bass. Big sheets also have a bunch of disadvantages, principally beaming and ringing: there simply is no free lunch—you can't have a big sheet in perfect…
Setup
Readers may be getting used to the lack of difficulty I experience setting up speakers in my listening room; I certainly am. The M-1s were positioned with their backs 7' from the rear wall (though there is an 8'-wide archway in the middle of that wall leading to a hallway an additional 5' from the back of the speakers), their centers 5½' from the side walls, and 8' apart. I sit 10' from the centerline between the speakers, this giving me a favorably high percentage of direct sound, mediating the tendency of my room to echo a bit. (The overall room size is 20' by 35', with 11½'…
Readers may be getting used to the lack of difficulty I experience setting up speakers in my listening room; I certainly am. The M-1s were positioned with their backs 7' from the rear wall (though there is an 8'-wide archway in the middle of that wall leading to a hallway an additional 5' from the back of the speakers), their centers 5½' from the side walls, and 8' apart. I sit 10' from the centerline between the speakers, this giving me a favorably high percentage of direct sound, mediating the tendency of my room to echo a bit. (The overall room size is 20' by 35', with 11½'…
Sidebar 1: Specifications
Description: Two-times three-way, bipolar, bass-reflex, dynamic loudspeaker. Driver complement: two 8" polyflex-treated, carbon-filled polypropylene woofers with PVC/nitrile surrounds; two 4½" trilaminated carbon-filled polypropylene midrange cones with foam surrounds; two ¾" treated-cloth hyperbolic dome tweeters. Crossover frequencies: 100/300Hz, 2.3kHz. Crossover slopes: most complex (see text). Frequency response: on-axis, 25Hz–23kHz, ±2dB; 75° off-axis, 25Hz–10kHz, ±2dB. Sensitivity: 83dB at 1m for 2.83V. Impedance: nominal, 6 ohms; minimum, 4 ohms.
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Sidebar 2: Review System
My equipment for reviewing the Mirage M-1s consisted of the same things I used with the Altec 550s reviewed in April—to much different effect, as you will see. Digital sound was provided by the CAL Tempest II, preamplification was Mark Levinson No.26, power amplification Levinson No.20.5, turntable the Well-Tempered, and cartridge the AudioQuest 404i-L reviewed by TJN in March running through the Levinson No.25 phono preamp.
One-third of the way through the review process, I was fortunate enough to try out the latest Win Labs FET cartridge through its own…
Sidebar 3: Measurements
Looking first at the manner in which the M-1's impedance changes with frequency (fig.1), the moderate peaks at 455Hz and 2500Hz are presumably due to the midrange and tweeter crossover filters. Overall, the M-1 should be relatively easy to drive, though the droop in the top octave would suggest that low-powered tube amplifiers should probably be best avoided. The fundamental box resonance is well-damped and appears at a low 42Hz, the bottom note of the string bass, while the port minimum lies at 28Hz, suggesting good low-frequency extension. This was confirmed by…