Music 680: Special Topics in Music Theory - Electronics in Performance (Fall 2006)
Class 3: September 25, 2006

Karlheinz Stockhausen / Mikrophonie I (1964) for tam-tam, electronics, and six performers
overview of the work
        a particular kind of interactivity
                "dual trios" of percussionist, microphonist, electronics operator
                via the shared tam-tam
                via the interdependence of the three performance roles
        introduction to the notation
                verbal explanation, onomatopoeia, and the scale of vowel brightnesses
				and the relationship to filtering: formants as an acoustical phenomenon
                but also rhythmic, pitch, and gestural precision
        introduction to the form
                moment-form as a series of self-contained gestures/textures/ideas
                        variety of possible durations but all internally unified
                variable arrangement according to a form-scheme
                        specifying the general dramatic arc of the piece but not its specific sequence
                        the "Brussels form" as a worked-out realization (and a standard of performance)

musical structure: moment-form
        division into "monadic" and "complex" moments
                most moments qualify as monadic
                        single or a small number of musical elements
                        typically either static or "punctuated"
                                contrasting center section, or contrasting / evolving conclusion
                                generally sounds exist /persist rather than evolve: material rather than process
                                        at least partly due to the nature of the tam-tam as an instrument
                                even "collage" moment only deals with 2 groups of materials (plus plucking)
                complex moments bear substantial responsibility for form
                        because of distribution in time: periodic insertions with emphasis on back-weighting
                        often involving reprises of monadic materials (X, Y, TUTTI 157)
                                intensification and reinterpretation (via reshuffling) of overall collage form
                        processual in nature: rhythmic and sonic development (cf. gradual changes in Y)
                        rhythmic/sonic connections between collaged materials (vertical and horizontal)
                                (cf. TUTTI 157)
                        as moments of focus / intensification
                                (TUTTI forte, TUTTI pianissimo)
                                strangeness (relative to other materials) as a crucial element
                                        in this case achieved through extension in time (both are long duration)
                                        and through coordination: TUTTIs are unusual in direct vertical relationship

issues for realization:
	filtering: what quality of filtering?
	ergonomics: how to make this viable for the electronics operators?
		can the original be improved upon?
electronics functions: amplification, panning, filtering
        audio modules and useful techniques
                amplification: quartic control
                        implement using Pd abstractions
                                inlet, inlet~, outlet, outlet~ objects facilitate creation of custom Pd objects
                                useful here since every audio function is duplicated for two musicians
                panning: constant power
                        panning front to rear as a curve between 0 and pi/2 radians
                                front output volume as cos theta
                                rear output volume as sin theta
                                [from trigonometric identity: (cos theta)^2 + (sin theta)^2 = 1]
                                        remember that Pd signal~ objects map the unit circle from 0 to 1, not 0 to 2pi!
                filtering: 
                        as an application of delay (and flanging)
                        using constructive/destructive interference to change the spectrum of a signal    
                        typically extremely short delay lengths; can be implemented with/without feedback
                                FIR filters are feed-forward; require longer delays to achieve a frequency spec
                                IIR filters use feedback; shorter delays relative to a spec, but can be unstable
                        "twicing" built-in designs for sharper filters: h[ h[ 3x -2 h [x]]]
        user interface
                MIDI fader surface
                        can't have both operators fighting over a single keyboard and mouse
                        (and indeed might even be preferable to use two separate control surfaces)
                        dual-fader-in-a-single-channel design of the original electronics
                onscreen display: slider objects, font changes, etc.
                control logic governing filter parameters
                        reducing 0-127 MIDI fader ranges to discrete filter steps
                        allowing "high bound" changes to reduce "low bound"
		possibility of automation: mockup of GERAUSCH moment

preview for next week: Babbitt