Digital sources: Mark Levinson No.31.5 CD transport and No.30.6 D/A processor, connected with Illuminations Orchid AES/EBU datalink, dCS 972 upsampler; California Audio Labs CL-20 DVD player, Pentium MMX 166MHz with Digital Audio Labs CardDeluxe soundcard connected to D/A via 75 ohm S/PDIF link, running Windows 98, WinAmp 2.5, and CoolEdit 2000.
Analog sources: Linn Sondek LP12 with Lingo power supply, Linn Ekos tonearm, Linn Arkiv phono cartridge.
Preamplification: Mark Levinson No.380S, Linn Linto phono preamplifier, Z-Systems rdp-1 digital control…
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Sidebar 2: Associated Equipment
Sidebar 3: Measurements
The MRM-1's designers apparently chose to optimize the design for bass extension, which means that its sensitivity will be low. I estimated 2.83V to raise just 83dB(B) at 1m, which is about 4dB lower than average. However, the speaker's impedance curve (fig.1) is relatively benign, dropping below 6 ohms only in the lower midrange. The saddle at 52Hz in the magnitude trace indicates the tuning of the reflex port, which in turn implies quite good bass extension. I assume the impedance peak at 21kHz is due to a notch filter used to kill the tweeter's ultrasonic…
How these individual responses sum across a horizontal 30 degrees window on the tweeter axis is shown in fig.4. The speaker's overall balance is flat though the top octave is still a little high, something on which I commented in my auditioning. The mid-to-upper-bass region is also lifted. This will be due in part to the nearfield measurement technique, but this LF generosity was also something I noted about the speaker's sonic character.
Fig.4 Mirage MRM-1, anechoic response on-axis at 50", averaged across 30 degrees horizontal window and corrected for microphone response, with…
In my listening room, the Mirage's balance (fig.8) was very flat, with good bass extension apparent. But if you compare this graph with those of other speakers I have reviewed, the slight excess of top-octave energy and the laid-back mid-treble can be seen.
Fig.8 Mirage MRM-1, spatially averaged, 1/3-octave, free-field response in JA's listening room.
As expected from its crossover topology and flat baffle, the MRM-1's step response (fig.9) is perfectly conventional: both drivers are wired in positive acoustic polarity, and the tweeter's output leads the woofer's by a…
Back in the spring of 1990, Stereophile introduced its first Test CD, featuring a mixture of test signals and musical tracks recorded by the magazine's editors and writers. Even as we were working on that first disc, however, we had plans to produce a second disc which would expand on the usefulness of the first and feature a more varied selection of music. The result was our Test CD 2, released in May 1992.
And now we have Test CD 3! While there is some overlap of the test signals with our earlier discs—it includes the useful audio-bandwidth warble tones from Test CD 2, but cleaned up a…
Channel Identification & Reference-Tone Tracks
[1] Home Theater & Stereo Channel Identification (DDD) 2:05
Left (Index 1), Right (Index 2), Center (Index 3), Subwoofer (Index 4), Surround (Index 5) channels, featuring almost the entire staff of Stereophile and Schwann Opus/Spectrum
Each stereo announcement is followed by 20 seconds of mono pink noise positioned in the appropriate playback channel. For those who like absolute accuracy, the sound-pressure level (spl) of the voices at the original session peaked at 100dB. The pink-noise level, however, should be around…
Music Tracks 3-5
[3] Empire Brass Quintet: "Sibley Sanctus Lydian" (DDD) 3:59
(from Passage 138 B.C.- A.D. 1611, Telarc CD-80355, surround-sound-encoded with the Spatializer™)
Composer: Rolf Smedvig, based on Gregorian Chant (KRS Publishing Inc./ASCAP); rhythm arrangement by Kurt Wortman
Musicians: Rolf Smedvig (solo trumpet); Eric Ruske (horn); Kurt Wortman (rhythm); with Jeffrey Curnow (trumpet); R. Douglas Wright (trombone); Kenneth Amis (tuba); Doug Lunn (fretless bass guitar); Pete Maunu (guitars); Laurie Monahan, Michael Collver (vocals); David Goldblatt (synthesizer)
…
Music Tracks 6-7
[6] Jimmy Rogers: "Blue Bird" (AAD) 4:44
(from Blue Bird, Analogue Productions Originals APO 2001)
Composer: J. Lane (Cordero Music/BMI, administered by Bug Music)
Musicians: Jimmy Rogers (vocals, guitar); Carey Bell (harmonica); Johnnie Johnson (piano); Jimmy D. Lane (lead guitar); Dave Myers (bass); Ted Harvey (drums)
Producer: John Koenig
Executive Producer: Chad Kassem
Recording Engineers: Mark Ettel, with Stefan Taylor
Recording Venue: Chicago Recording Company, Studio D, Chicago, IL
Recording Date: November 18, 1993
Microphones: Neumann M…
Music Tracks 8-9
[8] Airto Moreira and the Gods of Jazz: "Nevermind" (ADD) 7:43
(from Killer Bees, B&W Music BW041)
Composers: Herbie Hancock, Stanley Clarke, Airto Moreira (Solimar Too/ASCAP, administered by Bug Music)
Musicians: Herbie Hancock (piano); Stanley Clarke (double-bass); Airto Moreira (drums, percussion)
Producer: Flora Purim
Executive Producer: Robert Trunz
Recording Engineers: Daniel Protheroe, with Anders Johansson
Recording Venue: Sound Design, Santa Barbara, CA
Recording Date: November 1989
Mixed at: Ronnie Scott's Studios, London,…
Tutorial Tracks: Microphone Techniques
[10] Microphone Techniques & Soundstage Maps (DDD) 6:08
2 omnis (Index 1), 3 omnis (Index 2), ORTF cardioids (Index 3), "shuffled" ORTF cardioids (Index 4), Schoeps SFM 6 "sphere" (Index 5)
Producer: John Atkinson
Recording Engineer: Robert Harley
Recording Venue: The First United Methodist Church, Albuquerque, NM
Recording Date: November 5, 1993
Microphones: two Brüel & Kjaer 4006 *" omnidirectionals with black (diffuse-field) grids; as above with EAR The Mic set to omnidirectional pattern; two AKG D190E dynamic cardioids…