.......exactly ...."facingness"
----- Original Message -----
From: Castiglione, Andrew P. -ND <[log in to unmask]>
To: Sursound List (E-mail) <[log in to unmask]>
Sent: 17 November 1999 17:17
Subject: sursound: One Voice One Speaker


>
>
>
>
> Sorry about the formatting... Came from NY Times web site... But an
> interesting article... Gets back to the "one voice, one speaker" basics of
> sound reinforcement idea...
>
> A New Dimension in Recorded Music
> By JAMES GLANZ
>
> When Thomas Edison first demonstrated his phonograph to
> packed houses in the 1870s, the feat seemed so remarkable that
>         listeners occasionally fainted. Digital recordings and
> stereophonic sound have created a much less impressionable listening
public,
> but Dr. William Hartmann, a physicist at Michigan State University,
> recaptured a little of the old magic when he played a radically new type
of
> recording for a jammed conference room during a meeting of the Acoustical
> Society of America two weeks ago.
>     The way Hartmann recorded and played back a Mozart string quartet in
> B flat seems simple enough that it is hard to believe that the showmanlike
> Edison did not try it himself. But acousticians who were there said that
> nothing like the demonstration had been achieved before, and that it
> provided a glimpse of a spectrum of recording techniques that could
> eventually turn up in living rooms of the well-to-do and at elaborate
social
> gatherings.
>     On two channels of an
>     eight-channel digital recording,
>     Hartmann managed to isolate
>     completely the sounds of the first
>     violin during the original
>     performance. He did the same with
>     the second violin, the viola and the
>     cello. In replaying the quartet, he
>     gave each pair of channels its own
>     speaker, built to have sound
>     radiation patterns broadly similar to
>     those of the stringed instrument, and
>     he arranged the speakers on the
>     floor just as the musicians originally
>     sat.
>
>     The result was seven minutes of chamber music in which the audio
> "image" of the players was all but palpable, an unachievable feat for
> two-channel stereophonic sound. And, the usually inevitable distortions,
> created by transmitting more than one instrument through a speaker, were
> absent.
>     "It was so convincing," said Dr. Leo L. Beranek, the dean of the
> world's architectural acousticians, who is at Acentech Inc., in Cambridge,
> Mass.  "You moved around and the instruments seemed to be coming from a
live
> group."
>     The seemingly live musicians also sound as if they are playing in
> the room where the speakers sit, since no reverberations from the hall are
> preserved on the recording. Beranek said he thought the setup could
generate
> its own reverberations and maintain the sense of live presence in
> surroundings ranging from a large living room to the New England
> Conservatory's Jordan Hall in Boston.
>     A sliver of the old sense of excitement is back, too, said Anthony
> Hoover, an acoustician and principal consultant at Cavanaugh Tocci
> Associates who led the session in Columbus, Ohio, where Hartmann gave his
> demonstration. "Not only were people thrilled, but there was standing room
> only," Hoover said.
>     Although the demonstration dealt only with a specific way of
> recording a string quartet, Hoover said the effort should be seen as an
> exploration of the possibilities that would be opened up as DVD technology
> allowed for more and more channels and speakers. "It's very clear," Hoover
> said, "that the industry is moving in that direction."
>     There are several good reasons Edison could not have recorded a
> string quartet in the way that Hartmann and his students, Zachary Constan
> and Timothy McCaskey, did. The project required computers with memory
> capacities of a gigabyte and the ability to handle eight channels of
> digitized music simultaneously.
>     And while the technology for isolating instruments from one another
> with "pick-up" or contact microphones has existed for at least several
> decades, mixing those sorts of recordings to produce the realistic and
> pleasing sounds of classical instruments is still far from routine.
>     And when it comes to reproducing the three-dimensional aspects of a
> string quartet, the complexity of the sound pattern radiated by just a
> single violin shows what the physicists were up against.
>     Studies by Dr. Gabriel Weinreich of the University of Michigan, have
> revealed that at sound frequencies below about 850 hertz, or oscillations
> per second, roughly a G sharp an octave and a half above middle C, a
violin
> radiates its sound almost uniformly in all directions. But above that
point,
> with higher frequencies and thus higher notes, the violin has what
Weinreich
> calls directional tonal color, meaning that the instrument emits sound
> louder in some directions and softer in others, with patterns that are
> different at nearly every frequency.
>     "All of that is folded into what we call the violin sound,"
> Weinreich said.
>     Such complexities in each of the individual instruments meld
> together in a way that depends on how they are arranged on the floor or
> stage, creating the dynamic, three-dimensional, acoustic presence of a
> string quartet.
>     Realizing that it would be impossible to recreate every detail of
> that acoustic image (a term used by analogy with visual images of
> three-dimensional scenes), Hartmann focused on what he thought were the
most
> crucial brush strokes, like realistic painters who convey a sense of space
> without reproducing every cornice, leaf and cloud.
>     He began by recording each instrument with two contact microphones,
> one affixed to the instrument's body near the squiggly "F hole" and one
near
> the bridge, as four Michigan State music students played the Mozart
quartet
> nicknamed "The Hunt" (K. 458).
>     The acoustic vibrations picked up by the two microphones were quite
> different; the relatively stiff bridge transmitted a greater range of high
> frequencies, many of them corresponding to harmonics of the principal note
> being played.
>     Hartmann experimented with different mixes of those pairs of digital
> recordings that made it sound as if the right tones were coming from the
> right places. But in order to do that, he had to send the sound through
> special loudspeakers with two sets of low-frequency woofers and
> high-frequency tweeters on the front and one set on the back.
>     On the front, one woofer-tweeter pair transmitted sound collected
> mostly from an instrument's bridge and the other pair played sound
recorded
> from the F hole. The back pair transmitted the F hole channel with some of
> higher frequencies filtered out, since more low frequencies tend to be
> radiated backward in a real instrument.
>     Then the loudspeakers were arranged like the corresponding players
> in a string quartet.
>     "If you want to pick up the cello stand and put it some place, why
> then the cello will be there," said Weinreich, who also attended the
> Columbus meeting. "The different tracks are very clean in recording the
> individual instruments," he said.
>     Weinreich said the arrangement also created at least a rough
> approximation of directional tonal color for each instrument. Scaling the
> set-up to a larger ensemble would not necessarily involve more channels,
> Hartmann said. For example, electronic switching might allot an individual
> speaker to a soloist and share the remaining speakers among the other
> instruments. For a symphony orchestra, he said, "obviously we're not going
> to have 100 channels."
>     If more string quartets could be recorded and those recordings made
> available, Beranek said, there might already be a demand for the system at
> classy social functions.
>     "They could just set this up and have it play," he said. "It would
> be very realistic and do the job just as well as live players."
>     But Hoover suggested that the work's significance might lie more in
> its general approach to using multiple channels rather than in this
> particular realization of a string quartet. The demonstration could be
seen
> as a first test of ways to use the multiple channels that are becoming
> available with DVD and related technologies.
>     Six-channel systems are available now, he said, and 10- and
> 12-channel systems are said to be in the pipeline. With the proper
placement
> of speakers, existing systems are good at conveying, for example, the
sound
> of a helicopter as it passes overhead in an action movie. But the extra
> channels are often wasted on music, which blares out of all the speakers
> equally.
>     No matter how good the new systems improve upon Edison's phonograph
> and its progeny, musicians warn that there is still no substitute for a
live
> performance.
>     "I fancy myself, within my budget, a semi-stereophile, and it's
> fascinating to see how close someone can get to the old absolute sound,"
> said Dr.  Robert Greenberg, a pianist and composer, who is chairman of the
> music history and literature department of the San Francisco Conservatory
of
> Music. Still, Greenberg said, the best live music involves "the
performance
> feeding off the energy coming up from the audience."
>     It doesn't matter," he said, "if it's a Bruce Springsteen concert or
> the Guarneri Quartet. If you want the thrill and discovery of the
> interactive act, then it has to be live."
>



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