John Atkinson measured the 500L, and I saw the results only after completing my auditioning. First, the 500L had a measured sensitivity of 86dB/W/m ("B"-weighted, measured with 20kHz-bandwidth noise). This is slightly higher than the specified 85dB figure, but within the margin of error. Fig.1 shows the 500L's impedance magnitude and phase angle, measured with our Audio Precision System One. The bass enclosure's bandpass tuning at 62Hz can be seen in the impedance minimum at that frequency. The minimum impedance is 1.98 ohms at 112Hz, but the speaker dips below 4…
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I only found out after beginning my auditioning of Mirage's M-1si loudspeakers that the film 2001, A Space Odyssey was, at practically the same instant, undergoing a brief theatrical revival in major cities around the US. I might have known. Perhaps it was the persistent Strauss melodies that rattled around in my head as I set them up. Perhaps it was the two 5'-tall monoliths that subsequently stared at me as I sat in my listening chair. For whatever reason, the M-1sis were an imposing sight, and the association with out-of-this-world events was not a difficult one to make.
True, the…
From the lute on track 5 (from Lord Herbert of Cherbury's Lute Book, HMU 907068) to the soloists and choir on track 6 (Pelham Humfrey, Verse Anthems, HMU 907053), the organ on track 7 (Bach, Trio Sonatas BWV 525–530, HMU 907055), the early Spanish music of tracks 15 and 16 (Johannes Cornago, Missa de la Mapa Mundi and Secular Music of 15th-Century Spain, HMU 907083), and the Russian Church music on track 18 (Russian Church Music, HMU 907098), there were no missteps with the Mirages. The organ was spacious and airy, the chorus as big, wide, and deep as it should be, the solo voices and…
Sidebar 1: Associated Stuff
The M-1sis were set up in Stereophile's 15.5' by 20' by 9' listening room. CD-based material was used for most of the auditioning, either original CDs or compilation CD-Rs dubbed from my own CD collection. The remainder of the system consisted of the Mark Levinson No.35 D/A converter, the Pioneer PD-65 CD player used as a transport from its coaxial digital output (and also, briefly, the C.E.C. TL 1 transport), the Rowland Consummate preamplifier, and the Bryston 7B monoblock amplifiers in their series mode. The digital interconnect was a Kimber KCAG coaxial,…
Sidebar 2: Of Monopoles, Bipoles, & Dipoles
For the benefit of those who may not have seen GL's review of the similarly conceived M-3si (or our earlier reviews of the original M-1 and M-3), a bipolar design differs from both conventional front-radiating loudspeakers and dipole designs.
The former, of course, describes 90% of the loudspeakers on the market. One or more drivers radiate from the front of an enclosure, which may be configured as a rectangular box (usually), or—if the designer is adventurous and the budget open-ended—as any one of a myriad of other shapes. The…
Sidebar 3: Measurements
The Mirage M-1si's impedance curve in fig.1 indicates a load which should be easy to drive. The magnitude of the impedance never drops below 4 ohms or rises above 8.3 ohms, except at the lowest and highest frequencies. The peak at 24.6kHz could be caused by a "trap filter" to tame the high-frequency resonance of the tweeter. The average tuning of the ports is 29Hz—indicated by the "saddle" between the double peaks in the bass magnitude plot. The smaller peaks at 300Hz and 2.5kHz are a reflection of the effective electrical crossover points, the former somewhat…
Tom Norton returned to the Mirage M-1si in October 1993 (Vol.16 No.10):
Though Stereophile's samples of the Mirage M-1si have long since gone back to the manufacturer, I recently had the opportunity to hear them in another application in a visit to the facilities of Widescreen Review. Editor Gary Reber had two pairs of them in his main audio/video setup, one pair for the fronts, another for the surrounds. No center-channel loudspeaker was in use when I heard the system, nor were there any subwoofers. The latter was a temporary omission—a new pair of subs from Mirage was expected any day…
Sidebar 4: Specifications
Description: Three-way, reflex-loaded, bipolar loudspeaker system. Drive-units: two 1" (25.5mm) titanium hybrid-dome tweeters, two 5" (127mm) injection-molded polypropylene-cone midranges, two 8" (203mm) Polyflex treated, carbon-filled polypropylene-cone woofers with 1.5" (38mm) voice-coils. Crossover frequencies: 400Hz, 2kHz. Frequency response: 25Hz–33kHz ±2dB (on-axis), 25Hz–20kHz ±2dB (30° off-axis). Usable bass response: –10dB at 17Hz. Sensitivity: 82dB at 2.83V (1m), anechoic, 86dB in-room. Nominal impedance: 6 ohms, 4 ohms minimum. Amplifier requirements…
Among the most hallowed of my ten or so (the number varies) personal commandments of high-end audio is the following (to be uttered in sepulchral tones with deep humility):
You have to spend a lot of money only to discover that you didn't have to spend a lot of money.
Needless to say, given the inherent snobbery of old-time tweaks and the fundamentalist fervor of recent converts, thousands of acres of old-growth forest have been pulped in the expression of all the conflicting opinions as to what constitutes the outer limits of true high-end performance, and at what price…
"For instance, some transformers are simply dipped into varnish; but the ones we're using are left in the varnish for 24 hours, which allows the varnish to filter into all parts of the transformer—so you'll find our transformers are very quiet. The transformer is also decoupled from the chassis by employing certain materials underneath to filter out mechanical vibrations. Otherwise, that noise is making the case vibrate. Likewise, because the [printed circuit board] is attached to the transistors, if the board isn't also decoupled from the casing, all of that is singing together."
"And…