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Reviewed by:
  • Virtual Bach
  • Eliot Handelman
David Cope : Virtual Bach Compact disc, Centaur Records CRC 2619, 2003; available from Centaur Records, Inc., 136 St. Joseph Street, Baton Rouge, Louisiana 70802, USA; telephone (+1) 225-336-4877; fax (+1) 225-336-9678; electronic mail info@centaurrecords.com; Web www.centaurrecords.com.

We seem to accept the achievements of machine composing at an alarmingly uncritical pace. In an article in the EE Times, Colin Johnson writes that "computers can compose a new Bach cantata, but cannot compose anything novel, because their algorithms merely encapsulate a particular style of music" (eetimes.com/at/news/OET20021230S0015). The reference can only be to David Cope, because no one else—as far as I'm aware—has produced work to substantiate the first and last of those claims. Since the mid 1980s, Experiments in Musical Intelligence, Mr. Cope's program, has been generating Bach-like inventions, Chopin-like nocturnes, Mozart-like symphonies or, as on this CD, Bach-like instrumental concerti and suites, at an unprecedented level of technical accomplishment. There are, in fact, no other contenders for machine-composed music anywhere approaching this level, in consequence of which Mr. Cope's work has excited enormous admiration and speculation. An article in New Scientist calls it a "requiem for the soul" (www.newscientist.com/hottopics/ai/requiem.jsp), and theorists like Leonard Meyer, Fred Lerdahl, Ray [End Page 91] Kurzweil, and Douglas Hostadter have expressed interest, approbation, and amazement (arts.ucsc.edu/faculty/cope/biography_page_2.htm).


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Figure 1.

Example from near the opening of the first section of Suite for Solo Violoncello.


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Figure 2.

Example from near the end of the first section of Suite for Solo Violoncello.

I seem therefore to be somewhat in the minority by remaining in wonderment as to how any of this stuff is actually generated. The theory is that a few carefully chosen pieces are automatically analyzed, separated into parts, broken down by commonality, and recombined into new works which, thanks to the preservation of "signature"—phrases and such that recur in a given style—come out sounding as though ghosted by the composer whose works have been sampled. Mr. Cope has written four books that detail the operations, and these have been praised for their lucidity and scope (see, for example, Michael Theodore's review of The Algorithmic Composer at mitpress2.mit.edu/e-journals/Computer-Music-Journal/reviews/25-2/theodorecope.html). Yet I find the descriptions, theories, and algorithms offered in these books mystifying. I don't see how they could not fail to produce an incoherent jumble of bits and pieces of destroyed music. Nor do I see how they can account for the consistently coherent pieces exhibited as the product of a program.

Figure 1 shows a few measures near the beginning of the first movement of the Suite for Solo Violoncello (my transcription: I've assumed that the performance on the CD uses Baroque "a," a semitone below A440). Note in the last measure how the F descends to E before rising to the top note of this section, G. Figure 2 shows a parallel passage toward the end of the first section, beginning identically but varied so that the "f" ascends directly to "g." It's as though the first phrase holds back from completing the upward scale so that a greater sense of resolution can be created upon its return. Small details of this kind add powerfully to the music's coherence, and many more could be mentioned. My question is how EMI knows how to do this sort of thing.

In order to try to enlighten myself I studied SARA, the Lisp program that accompanies Virtual Music (Cambridge, Massachusetts: The MIT Press, 2001), which then seemed to be the most extensive and revealing program Mr. Cope has made public. Buried within it are functions like "schenker-plot," "translate urlinie," "layer-analysis," whose names promise potentially interesting theoretical techniques to handle the kinds of problems that EMI handles so well—ensuring that the music expands its highest register by degrees, creating long-range purposive movement upwards, getting a...

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