[sdiy] QTC and delurk

Scott Gravenhorst music.maker at gte.net
Mon May 14 13:11:54 CEST 2007


"Paul Perry" <pfperry at melbpc.org.au> wrote:
>I believe there is a proprietary bass frequency detection algorithm, that
>detects the frequency of a note, from only a part of the first cycle of the
>note. (this won't look much like a sine wave.)

This sounds like what the GR-50 guitar synth does.  Roland says it measures dv/dt for
the first quarter cycle and begins the attack portion of the sound with that guess.  It
then continuously adjusts pitch using more direct methods.  The guess is close enough
that the attack sounds good and corrects fast enough that it isn't noticed.

>It is intuitively possible that this can be done, if you imagine a physical
>analogue.
>A neural network algorithm was used, I seem to remember.
>
>(alternatively, I can imagine looking at a family of the initial fragments
>of the first cycle of the alternative possible notes, and seeing which fits
>best to what is seen).
>
>Paul Perry Melbourne Australia
>
>-----Original Message-----
>
>
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-- ScottG

---------------------------------------------------------

-- Scott Gravenhorst
-- GateMan I - Xilinx Spartan-3E Based MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
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