SOUND
MANDALAS
Lawrence
Ball, 22nd February 2001
1.
INTRODUCTION
The term Sound Mandala was suggested by Terry Riley, although earlier
the (not sure what to call them) were called UFO tones and later "Shapetapes".
Apologies if any of this is hard to understand, I will attempt any
angle, depth or aspect of clarification, don't hesitate to ask. Apologies
also for the slightly pig's breakfast" order of these notes.
This work dates from 1983, and I'm still trying to evolve an understanding
of this.
Please
be aware its for me a bit like trying to describe a huge magic cave
of possibilities that goes a long way into the hillside. If any of
you can understand it, it would be really great to get some thoughts
on where to build the roads from here.
2.
ORIGINS/INSPIRATIONS/OVERVIEW
LaMonte Young's work particularly with long held continuous pitches
has always inspired me; the late John Whitney (Sr)'s films and moreover
his principle of "differential dynamics" led me to apply
an extension of such techniques to timbrally-varying drones, (the
tamboura also was certainly present as muse), although later its been
applied to scores and midi. So initially it began life as a 128 harmonics'-modulating
tone/graphics audio-visual sequence where one sees the magical transforms
one hears.
2.1 Whitney's Differential Dynamics
(see Whitney's out of print book 'Digital Harmony' McGraw Hill (1980?))
A Hundred point "radius": Imagine
100 points (or more, or less) forming the radial line of an invisible
circle. Imagine each point, prepared to set off on a circularmotion
at a distance from the circle's centre which is equal to its initial
distance from it. If moving at the same angular velocity, the points
would move in rotation like a stick connected to the circle centre.
But- now start off again with each of the 100 points moving with an
angular velocity proportional to an index number from 1 to 100 assigned
to each point, numbered from one end to the other (it matters not
from which end - each option has interesting and beautiful outcomes).
This is best timed to last between 10 and 30 minutes (I feel). At
first, a winding spiral dominates, but winds itself to 'break-up'
point at which stage crystallisations and dissolutionsof order begin
to occur.(These are really good).
At
the end of the cycle, point 1 ('speed 1 also) will have done one complete
circle orbit, point 2 - 2 circles, point 3 - 3 circles etc. upto 100
orbits for point 100. So the cycle at this point would begin again
from a line identical to the position of the start. At the 'halfway'
stage, all the odd numbered points will have covered n/2 (n divided
by 2) laps (where n is the point's index number), which will be 'an
integer plus one half' orbits, forming a line halfway around the circle
from the start position. The even numbered index points will all
be at their start position.
In
fact, any fraction up to a denominator of about a fifth or a sixth
of the number of points plotted will yield a figure like this halfway
shape- but having a number of projecting radial arms equal to the
fraction's denominator.
This
results in a quite breathtaking display of simple forms emerging from
and dissolving into the teeming of moving points.
Another
elementary way in which the principle can be demonstrated:
A
line of points may be drawn along the leftmost (say), column of a
screen. 256 points (say), are each assigned a row of of the screen
to move along to the right . Upon reaching the far end of the screen,
the points may either reappear at the opposite edge to move again
from the left, or , as an alternative system, each one could 'BOUNCE'
, i.e. travel backwards, and then eventually forwards again.
Making
the points move at speeds proportional to their respective index number,
as described earlier gives rise to comparable effects to the circle
system, only with vertical instead of radial alignments at the crystallization
points.
Maybe
this is how an ant would perceive a 128-harmonic tone or a JI chord
if it were a) musical and b) its time sense was slowed sufficiently??
3.
ORIGINAL EXPERIMENTS
Initially, the question arose- "What happens if I apply Whitney's
differential dynamics to the points in a wave table?"
Imagine
a sine wave, composed (8 bits- this is 1983!) point 1 moves from its
initial position, incredibly slowly, when it reaches the maximum value,
its starts downwards again, and bounces back up again when reaching
the lowest possible value. It completes a cycle in say 44 minutes.
Point 2 completes 2 cycles of movement, and arrives back at the start
point in the same 44mins. Point 3 will do 3 cycles &c &c.........and
point 256 will have completed 256 cycles.
The
sine waveform had index numbers assigned to each point (for speed
assignments) from 0 (!) at the left (say) end, to 255 at the right,
I found that a sonic journey (through 400,000 timbres) was produced,
easily fascinating enough - even on one pitch, which journeyed through
complex timbral 'states' formed from many combinations and amplitudes,
gradually changing, of 128 harmonics. An 'orchestral', 7-octave sheet
of tone-anchored from one, low fundamental.
I
ran this timbre-itself-harmonically-transforming on a low B with the
2 speakers fractionally detuned to create a mobile phase loop. Its
like applying the laws of sound and harmonics of Helmhlotz's "atmospheric
ocean" to the shape itself of the sound waves on that ocean.
It quickly became known as "the tone",and "the UFO
tone".
The
sounds resulting are smoothly varying modulations of timbre that can
be very satisfying or stimulating or both, to listen to. I prefer
the changes on the slower side.
3.1
Timbral Analysis
A very thin ripple of amplitudes (1 or sometimes 2) harmonics wide
runs slowly up and then down the harmonic axis (from 1 to 128 and
then back the same way) forming a difference tone at the fundamental
resulting from the ascending (ie n+1th) and descending (ie nth) harmonics.
4.
BOUNCE MK 2 - MODIFIER SHAPES
A modification of the assignment system of speeds to points was then
developed. Rather than always having the linear array of points moving
at speeds proportional to their "index number" , it became
desirable to assign the speeds in different ways. Such as having the
middle points in the sequence travelling fastest, and those at each
end slowest. Or vice versa. This gave rise to the concept of a MODIFIER
shape. In the elementary system described before, a graphical shape
of position in sequence plotted against speed was a ramp form (either
ascending or descending). If fastest (or slowest) speeds are assigned
to the middle, this can be called a VEE (because of its shape) or
TRIANGLE modifier.
In
another variant, fastest (or slowest) speeds are assigned to the 1/4
and 3/4 positions along the sequence of movable points. The most successful
sound/visual combination (on the video/Sound mandala piece called
Triangles') was a triangle wave starting point (this now referred
to as the SEED form, with 'two triangles' as a modifier. (Two 'mountains'
with maximum speed at 1/4 and 3/4 points. The two halves of the image
were set to move in different directions at the start. Many nteresting
forms arise, which suggest Inca designs. The timbral and graphic sequences
are each characteristic of a particular quality, right through the
whole cycle.
4.1
Timbral Analysis
These sound sequences (or tones as they have been called) create on
the palette of 128 (or more of course) harmonics constellations or
virtual harmonics, gathering, scattering and reforming eg a ripple of amplitude
running up and then down the axis of harmonic numbers. If I start
with a sine wave and modify it with two humps (like the modulus of
a sine wave- values without a minus sign), and starting by moving
the left half up and the right down I get a strange bundle (looking
at a dynamic FFT) of harmonics 4 or so harmonics wide, travelling
up and down.
5.
EDIT or PREDESIGN?
We (my then students Michael Tusch, James Larsson and other friends
in the 80s, and now Dave Snowdon in the 90s and 00s) decided we like/d
to listen to an unedited algorithm, rather than edit fragments a la
Shakespeare with portions, we have gone for designing the action into
the spec. (in the envisioning of the characteristics and the ramifications)
rather than cutting up bits. This I feel is an interesting paradigm
approach for all kinds of computer-generated art. More organic? What
do you think? John Whitney Sr had a bad reaction to this approach
at first, but when I later met him, and discussed/elaborated it, he
seemed much more open to what I had been doing.
6.
FROM BOUNCE to SEQUENCE: DIFFERENTIAL DYNAMICS TO HARMONIC MATHEMATICS
We quickly generalised Whitney's principle to not only governing motion
(controlled by a large 1D array of integers) but also the movement
through a table of values (instead of just travelling at constant
rate, points would sweep through eg a timbre wave table's values,
each at a different integer rate).
I
wanted then to make the motions do better than simply go up and down
and back to where they started. I conceived of a sequence of values
(i.e. positions) through which each point moves, but, again, at speeds
related to assigned integer values, which are in turn in whole number
ratio (and hence harmonic) to each other. Hitherto, each point moved
up, bounced, moved down, bounced, and moved back to starting point.
A
harmonically constructed complex timbre form, (eg a timbre with harmonics
1,2,3,4,6,12 with amplitudes gradually decreasing) is used instead
to control the movement sequence of each point. This 6-harmonic timbre
gives rise to a sequence of intricate, smooth bobbing motions, each
point gradually rolling in and out of alignment with others.
The
points' motion in this more complex way I call SEQUENCE technique.
The
crystallization points are spectacular in different ways, the way
in which they are approached are also, being not simply an 'overtaking'
process, but also having unrolling and twirling motions, implying
a 3-dimensional interpretation. Also one gets "magic carpet"
effects where layers of points waver and hover.
'Helix'
uses a timbre, comprised of those harmonics 1,2,3,4,6 and12, as a
sequence. The points start off as a horizontal line (silence), and
each point moves through the sequence at a rate proportional to its
distance from the left hand end. (i.e. a ramp modifier).
The
timbral journey resulting consists of the 6 harmonics "themselves
going
on a journey" up and down the 7-octave spectrum of that synthesizer,
at a
speed proportional to the no. of the harmonic.(ie at speeds 1,2,3,4,6,12).
This I gleaned from FFTs I ran in the 80s.
Why
these particular timbral/harmonic motions ? I don't know, and would
like to know, so I can find interesting variant animations of these
harmonics' ripples. Doing an FFT is one thing, predicting how to get
interesting results is another. Help!
The
maths of how and why specific harmonic processes result from the seed
and modifier shapes (in BOUNCE technique) and from the modifier and
sequence tables (in SEQUENCE technique) still evades me.
Thanks
if you got this far.
Let
me know any feedback if anyone finds this useful or inspiring I'd
be glad to know about it.
Yours
mathematically, musically and spiritually
Lawrence Ball
composer, math tutor, director Planet Tree Music Festival
http://www.planettree.org
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