The Stereophile Test CD Tracks 6-9

Track information, Tracks 6-9

[6] E. E. Bagley: The National Emblem (ADD) 1:18
Nether Providence High School Band
Recording Venue: Nether Providence, PA
Recording Date: 1948
Recording Engineer: J. Gordon Holt
Microphone: Brush crystal
Recorder: Brush BK401 Sound Mirror ¼" open-reel recorder (mono)
Transfer to digital: Nakamichi 1000 R-DAT
Digital Transfer Engineer: Robert Harley

[7] Theodore Dubois: Les Sept Paroles du Christ (excerpt) (ADD) 4:32
Philadelphia Oratorio Choir
Recording Venue: First Baptist Church, Philadelphia, PA
Recording Date: 1961
Recording Engineer: J. Gordon Holt
Microphones: two Sony C37 cardioids in ORTF configuration
Recorder: Ampex 601/2 ¼" open-reel recorder at 7.5ips (NAB EQ)
Transfer to digital: Nakamichi 1000 R-DAT
Digital Transfer Engineer: Robert Harley

[8] Maurice Ravel: Chanson hébraïque (Absolute Polarity Test) (ADD) 2:34
Sam Jones (tenor), pianist unknown
Recording Venue: University of Wisconsin
Recording Date: 1964
Recording Engineer: J. Gordon Holt
Microphones: two Sony C37 cardioids in ORTF configuration
Recorder: Ampex 601/2 ¼" open-reel recorder at 7.5ips (NAB EQ)
Transfer to digital: Nakamichi 1000 R-DAT
Digital Transfer Engineer: Robert Harley

[9] Armas Järnefelt: Praeludium (ADD) 2:31
Delaware Symphony Orchestra (in concert)
Recording Venue: Wilmington Opera House, Wilmington, DE
Recording Date: 1977
Recording Engineer: J. Gordon Holt
Microphones: two Sony C37 cardioids in ORTF configuration
Recorder: ReVox A77 ¼" open-reel recorder at 15ips, with dbx noise reduction (NAB EQ)
Transfer to digital: Nakamichi 1000 R-DAT
Digital Transfer Engineer: Robert Harley

These four recordings made by Stereophile's founder, J. Gordon Holt, were selected from many hours of tape, and we are sure you will agree that the venerable JGH (in whose ears we trust) is truly talented when it comes to picking the best spot to place his pair of microphones. We are particularly proud to be able to present Gordon's very first tape recording, made in the year the magazine's current editor, John Atkinson, was born! (Gordon was 18; American tape recording was 2!)

A note on Gordon's preferred microphone technique as used in the three stereo tracks: "ORTF" refers to a technique devised by the French broadcasting organization (Office de Radiodiffusion-Télévision Française) whereby two directional ("cardioid") microphones are angled at 110 degrees and spaced apart by around 7", the average distance between a human being's ears. The two microphones basically encode the directions of the voices and instruments by the different loudnesses they pick up. In itself this would give a very narrow stereo image—"fat mono" is how one writer described it—but by spacing the microphones apart, a little time information is added which ensures that the image extends across the full spread of the loudspeakers. (Sound reaching the microphones from the left, for example, will reach the left-facing microphone approximately 0.7ms before it reaches the right.)

This is but one of a number of "purist" techniques, all of which share the characteristic of being able to capture a "real" soundstage, so that the listener's loudspeakers seem to disappear. Individual vocal and instrumental images on tracks 7-9 should be precisely located in the space between and behind the loudspeakers.

Track 8 features an "absolute phase" demonstration. The sound starts out with its overall polarity one way around, but finishes with its polarity inverted. According to many writers, especially Clark Johnsen in his book The Wood Effect (footnote 3), the sound of human voice and many instruments will be more natural with the polarity correct—ie, so that an acoustic compression that reaches the microphone will be reproduced as an acoustic compression that reaches the listener's ear—than it will the other way. We have no idea which way 'round on Gordon's recording is correct, but as we have inverted the polarity somewhere in the middle, you will be able to hear for yourself if there is an audible difference between the two states. And can you identify where the change in polarity occurs?



Footnote 3: Clark Johnsen's excellent The Wood Effect is available from The Modern Audio Association, 23 Stillings Street, Boston, MA 02210. Tel: (617) 357-8040. Price: $7.95 plus $1.05 shipping and handling.
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