Neubäcker says that he spent time looking at spectral analyses, seeking "structures in the signal" that could identify a chord's fundamental notes and link each of them with its own overtones. Because sound waves blend and interfere with each other, this is a hideously complicated task. But as Celemony's demonstrations show, it's one that Neubäcker has apparently accomplished.

Direct Note Access represents the notes of a chord graphically: they look like blobs of ink on a timeline. The blobs can be moved up or down to change their pitch, or back and forth to change their timing. An existing chord can be changed from major to minor; notes played at the same time can be strung out to occur in sequence, in what's called an arpeggio.

Neubäcker is quick to admit that the software isn't perfect. It works well with clean, unprocessed instruments, such as acoustic guitar or piano. It will work on a heavily distorted electric guitar but may, for example, read some high-pitched harmonics as separate notes.

Nor is the software quite the equivalent of a human ear, able to distinguish actual instruments from one another. Like an audio idiot savant, it can tease individual notes out of a complicated six-note chord. But feed it a recording in which two instruments are playing the same note--say, the trumpet and piano on an old Ellington record--and it will treat them as a single entity, rather than distinguishing their separate voices.

Like Celemony's Melodyne, Direct Note Access is likely to find its way quickly into studios' tool kits.

"I've seen the video, and I was blown away," says J. Chris Griffin, a producer at the Cutting Room studio in New York, who has worked with such artists as Madonna and Kelly Clarkson. "I can't wait to try it. I'm definitely planning on getting it."

The tool may have cultural costs as well as benefits, however.

Already, vocal tracks on virtually all radio-ready albums are cleaned up; they're perfectly in tune and in time but may lack the unique character of a vocal performance by, say, Billie Holiday or Bob Dylan. Direct Note Access's power could accelerate that homogenization of pop music, says Berklee's Bierylo.

Direct Note Access will be released commercially this fall as a plug-in compatible with most major audio-recording software packages. A stand-alone version will be released later.

But Neubäcker is already thinking about ways to expand the tool's capabilities, perhaps even allowing it to recognize and distinguish the sounds of individual instruments.

"My approach is not to focus on making a product but to understand what sound is all about," he says.