[sdiy] Chance music - more

[Peter Grenader]

Someone contacted me offlist about what I touched upon on chance or
aleatoric music that I thought some may find of value?  Here goes:

To answer your question, no -- the chance elements in a chance piece needn't
come from the physical world, they can be generated by any means. But they
SHOULD be determined from a defined process - that's the key.

When one studies music in college, especially composition, you are shown
many different musical forms - allegro sonata, 12 tone, chance, many of
them.  It is customary to then be assigned to compose a piece incorporating
that form after the instruction.  If you were assigned to compose a chance
piece, and did nothing more than use a sample voltage to control various
parameters of a piece of music - rhythm, pitch, timbre, location, etc - it
would in fact be chance music, but I wouldn't expect to get anything higher
than a D for such little effort at a college level.  But there are many
processes which would yield more interesting results and in fact get you an
A!

One famous example is Charles Dodge's Earth's Magnetic Field.  He used
periodic NASA readings of  the EMF's magnitude as a pitch and rhythmical
score.  The results were fascinating and the work was released on  Nonsuch
amidst a lot of fanfare in the mid seventies .  One may argue if these
readings were in fact determined by chance, but you can argue than for any
random process - the amount of random, it's pureness - that argument would
(and has) gone on forever and personally,  it drives me bats.  The Buchla
Source of Uncertainty had only 265 different voltages to choose from in it's
selection of the next 'random' element  - not a lot - but the result was
very interesting and to most, useful psuedo-random

I actually got a commission to compose a piece of chance music a million
years ago because somebody found the process I had set up to be interesting:
It consisted of taking a series of cameras on the overpass of a five lane
highway (freeway, turnpike, autobahn, whatever).  Pictures were taken
simultaneously from each camera at regular intervals. This is how pitches
and polyphony was determined. Their duration was calculated by the length of
the vehicle in the crosshairs of the lens at any given frame. The color of
the vehicle also had a baring, with rules allowing for glissandos rather
than incidentals if the vehicle happened to be two wheeled and crossing
lanes when a picture was taken. Inflection was determined by the location of
the vehicle over the sampling region. One final rule allowed me to raise or
lower a given note an octave if the driver had their turning blinkers on and
it was transposed in the direction the indicator was 'pointing'!!

Later on all of the photos we examined and plotted in a single score of
about 3 minutes (this was all the film my tiny grant allowed for). This
particular realization of the score could be considered more translational
than chance in nature in that certain liberties were taken and a result the
outcome is remarkably tonal - but I set my rules up so that would happen.
That part was NOT by chance.

 I was free to set up what time of day to do this and I sat on that chosen
overpass many times to determine one in which the result wouldn't end up
sounding like a bunch of crap, or drones consisting off all notes on the
staff, which would certainly be the case if we had done this at rush hour.
Not that that would be bad, it's just not the result I wanted.  Again, while
chace elements were involved, they didn't rule the roost - I did.

The net result was largely bullshit, but there was about 30 or so seconds of
brilliance.  In 2002 I actually converted that 30 seconds to midi and put it
through my TX816. You can hear it on my second music samples page (older
works)  at buzzlick-music.com -  Scroll to SPACE GROOVE.  I go into some of
the history of chance music there, you might find it interesting.

Anyway, I hope this helps.  With all music, what makes chance music good is
the process - chance just frees some of the parameters out of the composers
control, but it is the composer who defines how that's handled.

- Peter