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June 2008
This was not exactly an A/B comparison test; the live performance was at 8 PM on March 17, 1990 at Jordan Hall, while the playback took place at our usual TSC (the Federal Transportation Systems Center in Kendal! Square) location 23 hours later. Steve Owades, past president of the BAS, is a member of the John Oliver Chorale, and was able to obtain tickets. The BAS Speaker • volume 18 number 2 page 2 to the concert at greatly reduced prices. Since the performance was the night before our meeting, and several members would be recording the session with very different microphones and setups, the concert presented a unique opportunity for BAS members to compare the sound of various recording setups with one another and with live music.
The Live Performance There were many microphones hanging in the hall. Out in front of the entire ensemble were a dummy head (a Neumann head specially modified by engineer David Griesinger), a pair of Schoeps spaced omnis (belonging to BAS member Micha Schattner), and a closely-spaced pair of Cambridge ribbon microphones, which have a figure-eight pickup pattern (also Micha's). Dave Griesinger also placed a Calrec Soundfield single-point stereo microphone over the woodwinds and two Neumann KMF 4i cardioid condensers pointing at the chorus (see the accompanying diagram.) Recorders used included PCM-F1s and both tabletop and portable DATs.
Playback Brad had spent Sunday afternoon transferring the same excerpt from various tapes of the session onto a DAT tape and preparing forms for the listening tests. The DAT format is ideal for the demonstration since it is very easy and quick to skip from one selection to another. Brad performed a single-blind test: he did not mention the microphone setups used for each selection. He wanted us to comment on the sound, and guess which setup was used. His main objective was to minimize any prejudices. The forms included spaces to indicate preferences on a scale of 1-10 in the categories of sound quality and balance for chorus, soloists, strings, brasses/winds, and the overall recording. Each attendee was also asked to specify whether (s)he had attended the concert, and if so, where (s)he was seated. There were additional spaces for the proportion of CDs and LPs in the respondent's listening habits, and the brand and model of loudspeaker. Names were not required.
The last five minutes of the piece were played on each of the following setups, in this order: 1) a mix of all of Dave's microphones—the dummy
head supplemented with the chorus mikes (Neumann cardioids) and solo array (the Calrec
Soundfield microphone); Among those who did not attend the concert, the Telarc CD was the favorite (5 votes), followed by Micha's ribbons alone (3 votes). Both the DG and Micha's omnis alone got 2 votes, with the last vote going for Micha's mix. With a greater weight for concert attendees, the tape made with Micha's ribbons alone was the favorite, followed by the Telarc CD. Preferences, as it turned out, were partly dependent on where one sat in the playback room. Those sitting near the front (including me) preferred the more ambient recordings, while those sitting near the back of the room preferred the drier recordings. Those sitting near the back moved forward after the formal evaluation, and some changed their preferences. My two favorites were the recording with Micha's ribbon microphones (#4), which has the least congested, most effortless sound (I correctly identified the selection as being recorded with the ribbon microphone), and Dave Griesinger's mix of dummy-head, chorus mikes, The BAS Speaker • volume 18 number 2 page 3 and solo mike array (#1). The former is closest to the balance I heard in the concert hall. The Telarc recording did well in the comparison. My ranked preferences are very close to the weighted frequency-of-first-choice statistics above. It was an enjoyable evening. This is the closest one can get to an A/B comparison between live music and various microphones and setups. We should all thank Brad, Micha, Steve, David Griesinger, Frank Cunningham (who collaborated with Dave on the on-site mix), David Moran, and Bob Brundage for making this meeting possible. — Poh Ser Hsu and E. Brad Meyer
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