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Re: OT: Apple has a patent on tremolo!

Jeff Evans wrote:
? Seems to me that what Kurzweil is talking about is merely that they offer a chance to specify the Hertz of a pitch instead of using a named pitch predefined by equal temperament. This would allow one to affect the beat rate produced by harmonic combinations, tuning for example a major third so that it was beatless, as in "just" intonation.

It could also be used, true, to create an artificial tremolo by slightly detuning two waves of the same nominal pitch, but the process is not automatic as it is in the patent. The patent covers an automatic method, simple as it is, of making an artificial tremolo constant over a wide pitch range.

But that doesn't mean I believe the the patent office actually looks at these applications.


What's to automate? Detuning by interval is a common procedure (as used for example in harmonizer efffects) - the interval might be as much as an octave, a major third, or some fraction of a semitone. The second way is a fixed frequency offset, as in the Kurzweil example - just as common. It is simply a matter of providing the parameter to the user. Both will likely be provided together, so you get conventional keyboard tracking ~plus~ the constant-Hz shift - as clearly described in the Kurzweil manual, and in the patent description and "circuit" diagrams.

There is even a third way to frequency-shift detune, which is to apply the fixed offset harmonic by harmonic, which ostensibly can only be done when the synthesis is by additive oscillator bank. This makes literally all beats the same - but of course the timbre detuned in this way becomes increasingly inharmonic (883/443 != 2) as the difference increases. It is a standard additive method to achieve structured inharmonic timbres. The sort of thing that might be left as a student exercise in classes teaching Csound, Max/MSP, etc. We even have pvoc (+ peak detection) processes dating back decades, that apply this linear frequency shift to a sampled sound.

All three methods are therefore long-established and standard practice. Any patent can only be valid if it finds some cheaper, faster or otherwise novel way to do it. To do this it first has to establish a ~genuine~ problem, where solutions either do not exist, or are expensive or intractable for one reason or another. There is no evidence of any such advantage even claimed in the patent (and, um, patently, the "problem" hardly exists as such), which simply thinks it has discoved the idea of frequency shift. Unless of course they are trying to patent addition?

Richard Dobson

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References: 
 >Re: OT: Apple has a patent on tremolo! (From: Paul Evenblij <email@hidden>)
 >Re: OT: Apple has a patent on tremolo! (From: Ben Cox <email@hidden>)
 >Re: OT: Apple has a patent on tremolo! (From: Richard Dobson <email@hidden>)
 >Re: OT: Apple has a patent on tremolo! (From: Jeff Evans <email@hidden>)



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