Collection VII

Lucas in White

Casey Mongoven

June 10, 2008

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Catalogue Entry B961 & Files
Parameters   Sequence Values & Graph
description of sequence: Lucas sequence; define a(0) = 2, a(1) = 1, for n > 1 a(n) = a(n - 1) + a(n - 2)
description of piece: This piece is based on Lucas harmonic partials. The fundamental frequency (1st partial) can be defined, but it must be 30 Hz or under. White noise is filtered with an FFT bandpass filter (or a Butterworth bandpass filter in another version). The filter makes a linear sweep upward from the fundamental frequency; this means that everything below the fundamental frequency is cut off in the beginning. The bandwidth expands as the filter sweeps upward until the filter reaches the next Lucas harmonic partial at which point everything below that partial is filtered out. Once the 843rd partial is reached by the filter, the piece ends. An anti-click envelope is used - see Csound file.
optional: Using a long piano string with a base frequency at or below 30 Hz, attach a transducer to the string at one end and a piezoelectric microphone at the other. Set the fundamental frequency of the piece to the same frequency as the fundamental of the string and send it through the string with the transducer, using the microphone to record the sound or play it back through a loudspeaker. Real-time is optional.
offset: 1
number of members used: 14
number of channels: 1
piece length: defined by base note value multipled by 2204
base note value: definable, .04138 seconds or greater
orientation: ascending
temperament: based on series of harmonic partials
lowest frequency: definable, 30 Hz or lower    highest frequency: lowest frequency multiplied by 843   
number of unique frequencies: infinite
synthesis technique: white noise filtered by bandpass filter
dynamic: definable, from ppppp to fff
synthesis language used: Csound