🚀 go-pugleaf

In article <8809071942.AA05026@cory.Berkeley.EDU> dillon@CORY.BERKELEY.EDU (Matt Dillon) writes:
>>>    QUESTION#2)  Is it possible with software and hardware capabilities
>>>                 to digitize a song and have the computer convert the
>>>                 wavelengths into notes/sheetmusic and then print it
>>>                 out?
>>>     **Any soltuions or ideas will be greatly Appreciated!
>>>
>>James Slattery
>
>	This is strictly a (read: major math) processing thing and is not 
>dependant on the particular graphics or sound capabilities for any computer.
>
>	Maybe on a mainframe, if it's possible at all!
>
>			-Matt

I was hoping that there might be some digital signal processing chips
available that might do the job, but I haven't done any research
in this area.  Keith Doyle suggested an array of filters as a substitute
for the FFT stuff.  This might work, but the filters must have a
bandwidth of 6% or less (assuming an equally tempered scale), and you'd
need at least 96 of them to cover the keys on a piano.

Once you get past the logistics of 96 filters, you run up against
another problem to which Keith made reference.  Harmonic content of
musical instruments.  If you had 96 filters with 6% bandwidth, each filter
tuned to the fundamental of each of the keys on the keyboard, then
when you press one key on the piano, you would get many filters
responding to the note that you hear.

To further complicate the issue, some instruments only sound on the
odd harmonics (like an oboe), and a trombone does not even produce
the fundamental!  So..... it is not a simple thing.

If you are using filters and you assume that you are transcribing
a single voice and the voice sounds on the fundamental, then
finding the fundamental is easy: it is the lowest pitched filter
that comes on at any given point in time.  Beware, I have a
patent on this type of music transcription process.
Doing much more is quite difficult, but I've been looking into it.

Oh.... good luck keeping all those filters tuned..... analog is
so much fun...  love those processes that don't work in hot weather...

An FFT soultion runs into all the same difficulties (except keeping
it tuned 8^)).  The FFT solution also has it's own set of problems.
Someday it will happen, but initially it will not be real time.

                                               kev
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