From this stage in the course onward we'll be looking for homework that departs from the starter code in creative ways. For this homework study, use FM synthesis to demonstrate the perceptual phenomena of "auditory streaming." Run the starter code examples, play with them to understand how they work and then invent replacements and variations which fulfill the assignment. Your Library/Web/220a/hw3.html page should reference files in your Library/Web/220a/hw3/ directory.
Refer to the earlier readings for background on both subjects.
FM SynthesisThe block diagram to the right (Figure 6.14 in the Computer Music Tutorial) shows a typical simple FM instrument.
Grab the starter code and study how it implements a version of this instrument in ChucK: hw3-starter.ck.
Likewise, visit the project presented in the coreLectureSequence "ck-clips" and study how it borrows the notion of movie-style "clips" and abstracts these into units to compose with: ck-clips.
The phenomenon of auditory streaming is a
In this assignment, you'll be using the FM instrument from the lab above to create multiple different sound sources, that then perceptually group as coherent sources.
Download the starter code, and create an auditory illusion that you like - shoot for one that maximally segregates the voices: hw3-starter.ck. The effect depends on differentiation of sonic parameters. Choose your own dimension(s) for the effect e.g., timbral, spatial and/or envelope qualities. Tune the effect by ear and make it different from the start code example. Then, re-program it in the form of a "clip" as described in ck-clips so that one "clip" creates a single (monophonic) streaming example.
We'll be listening to hear the effect of a slow note sequence blossoming into illusory polyphonic lines as it increases speed. In addition, make it into a musical study in which the illusion is present but it's not the only thing going on. Invent some other FM-based sounds to go with it and layer them in as clips. These don't need to be streaming illusions, they could be e.g., a melody, a rhythm, an ambient layer, etc. Concoct at least one big musical change (your choice of what that is, but it should be obvious to the listener) and shoot for a total duration of around 1 minute.
As with HW2, do your work in four channels, even if you don't use all of them all the time. Take advantage of sound arriving from different angles and if you want to, use the spatial dimension as one of the "differentiators" that creates the streaming illusion. Convert the final 4 mono .wav files to a combined 4-channel ambisonic file.
Submit to the Homework Factory an HTML file titled hw3.html that includes the following: