Music 680: Special Topics in Music Theory - Electronics in Performance (Fall 2006)
Class 2: September 18, 2006

John Cage Imaginary Landscape no. 1 (1939)
	introduction to the work
		works integrating instruments and electronics: new compositional resources
		Cage and percussion music as timbral novelty
	sinusoidal synthesis
		for Cage, because this is the technology available: test-tone records
			[and radios - until tape becomes available with Williams Mix in the 1950s]
			later works (Credo in US) using vinyl in a more collage-oriented, "DJ" fashion
		Cage's work as precisely but also practically scored
			unfortunately, insufficient information regarding contents of records
				or about the style and capabilities of the turntables used
			concentrating on the present rather than anticipating the future
			[show photographs of the actual LPs]
		"Composition is written to be performed in a radio studio."
		sectioning of the work
			measure structure: 5+5+5+1, 5+5+5+2, 5+5+5+3, 5+5+5+4
				doesn't have the fractalization pioneered in the three Constructions
					(and later used in the Sonatas and Interludes)
				but note the importance of unusual lengths: measures of 6/4 and groupings of 5
			material structure: a+a+a+b, a+b+a+b, a+b+a+b, a+a+b+b
				where a is defined primarily by inside-the-piano strums and cymbal rolls
				and b is defined primarily by muted piano ostinato

Alvin Lucier / Still and Moving Lines of Silence in Families of Hyperbolas (1973-74, 2nd version 1984)
	sinusoidal synthesis as acoustics
		for Lucier, single frequencies can be used to palpitate particular acoustical facts
		integration of acoustical concept & composition = career commitment to sines
	beating and standing wave phenomena
		two closely-tuned sinusoids will "beat": perceived as a single pitch with amplitude change
		standing waves are wavelengths tuned to fit the physical dimensions of the room
			wave crests and troughs are audible locations in space
			wave nulls are inaudible locations in space
			amplitude varies by physical location in the space
		get acoustics dimensions from Benade
		Lucier's first instantiation as incredibly open: happening-style
		second instantiation is quite specific but all in prose
		Lucier: wide-open nature of first instantiation
		what is the appropriate form or structure of a performance? "Incessancy"
			extremely linear and demonstrative nature of second instantiation
			typical simplicity and process orientation of Lucier's music
technical issues for Cage realization
	what are the correct frequencies given the ambiguous relationship between score and recording?
	control of sinusoids
		frequency: logarithmic vs. linear sweeps, mtof object
			(2^([deviation in cents]/1200))*[starting frequency in hertz]
		amplitude: logarithmic vs. linear ramps: linear, quartic, dbtorms object
			quartic as a similar curve to logarithmic but with a true zero
				(logarithmic curve only equals zero at minus-infinity)
		static placement as "historically authentic" for Cage 

Pd revisited
	array of "objects" on a "canvas"
	right-click on any object for a help window, with demonstration and related references
	distinction between "audio" ("tilde"/"~") and "control" objects
		"audio" objects compute at audio rate: smooth, click-free, computation-intensive
		"control" objects compute less frequently - use where audio rate is not necessary
	osc~ - sine oscillator
	dac~ - output to audio driver / soundcard / loudspeakers
	+~ - sum audio signals (mixing)
	*~ - multiply audio signals (amplitude envelopes, ring modulation, etc.)
	line~ - control frequency, amplitude, etc. at audio rate
		lists (expressed in messages) as the correct way of communicating with the line~ object
	"number box" - simple form of user input and display output

sinusoidal synthesis for Imaginary Landscape no. 1
	two turntables as two sine oscillators: produce fixed, changing frequencies
		line~ objects control pitch of osc~ objects
		independent line~ objects generate amplitudes
		amplitude set through *~
		oscillators mixed through +~
		output gain scaled through *~
		scaled, mixed, output sent to dac~
	this is the fundamental technique for additive synthesis!

sinusoidal synthesis techniques more generally
	additive synthesis
		any acoustical event can (theoretically) be analyzed and resynthesized as a sum of sines
	modulation synthesis: to be covered in detail on October 30
		ring modulation and sidebands
		amplitude modulation and the input signal
		frequency modulation as an extension of vibrato

preview for next week: Mikrophonie I