[sdiy] Music

[Scott Gravenhorst]

Scott Nordlund <gsn10 at hotmail.com> wrote:
>
>>>Good results, it's a really pleasant tone.  What's generating the
>>>pitches?
>>
>> There are two FPGA instruments. One is a 56 string digital harp 
>(phsyical model), the other is a > 16 voice 8 operator FM bell 
>synth. The bell synth has some of it's signal passed thru a lowly 
>MXR > Phase 100. 
>
>Are you following Julius O. Smith's stuff for the physical 
>model?  I've looked into his work but only tried it in a really 
>naive sort of way.  Very rich territory though.

The strings are simple one dimensional Karplus-Strong models.  In fact, there aren't even any
fractional delay filters involved, so very simple.
  
>
>I'd love to see someone try gong/cymbal/acoustic instrument 
>resonator model, but I think that's still a little too crazy for 
>right now.  My own not very well considered efforts all sounded 
>like microphone feedback or defective reverb. 

I've looked into this subject with little success.  I've been able to make some fairly convincing
ride cymbal sounds using FM (total of 16 operators per cymbal though).  

For a short time, I looked into using some special filters with karplus-strong models, all pass
with a nonlinearity which moves energy to higher frequencies.  I think that many of these are
needed to adequately model an instrument like a cymbal.

>> They are both driven by a sequencer that generates semi 
>structured phrases of notes. The scale is > entered as a set of 
>probabilities per chromatic scale note to play on any given beat. 
>An array is > initialized with random notes to play based on the 
>scale probability table. The array is "played" > through, one 
>item per beat and then repeats. When the array has been 
>completely played, one note's > pitch value is changed based 
>again on the table's values. This is done for two parts. 
>
>Shocking understatement of the century: algorithmic music is hard!

heh, yeah, harder than it appears on the surface.

>I got kinda tired of the diatonic/modal noodling type random 
>stuff so I tried something different.  To get it not static but 
>also not incomprehensible is really difficult. 
>
>Another idea that's been brewing for a few years: I came up with 
>a chord progression generator based on an "increment sequence".  
>Imagine a mod-24 counter (spanning 2 octaves of chromatic notes) 
>that is incremented by some sequence of intervals, and the 
>resulting stream of numbers is split up into groups of 3 (or 
>whatever) to make chords.  So a sequence of "0, 4, 3, 0, 3, 4" 
>with each set of 3 notes forming a chord will play alternating 
>major/minor triads around a circle of fifths over a 2 octave 
>range.  Throwing in some more complex (but carefully considered) 
>stuff can get something more exotic, sort of impressionistic 
>sounding.  It's kind of like serialism but doesn't sound so 
>rigorous.  I used to do this manually but it's way, way too 
>tedious.  It also seems well suited (if not particularly 
>intuitive) to the 19-TET scale, since you can make a "circle of 
>anything" in that. 

Interesting idea!

>I kinda figured that since my music ended up turning into strange 
>sounding chord progressions, if I can get something to do it for 
>me I can sorta write myself out of the creative process. 

LOL...  I'll tell you one thing - aleatoric generators tend to "think" of things I never would.

>> I'm still working on this sequencer - no doubt - I think it will likely
>> never actually ever really be finished.
>
>I know the feeling.  I've got a million ongoing things in PD and 
>I'm always getting inspired to start more.  Everything I do can 
>easily be re-purposed, though, so it works out. 

One of these days, I need to play with PD.  I keep hearing lots of good things about it's capabilities.

-- ScottG
________________________________________________________________________
-- Scott Gravenhorst
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