October 24

Thought for the day: Sound is layers upon layers of motions (some coupled, some just adding)
and music is even more layers. Long-term structures coexist or interact with very short-term ones.
Sound and music analysis uncovers structures, composers create them. Acousticians and
psychoacousticians, as well.

Examples through today:
  • sines.scm
  • sweep.scm
  • impulse.scm
  • noise.scm
Signal synthesis
fm.scm (hw#1)
bird.scm (hw#2)
periodicity
sampling rate / Nyquist frequency
dynamic range
Signal processors
tube.scm (hw#3)
finite impulse response
infinite impulse response
difference equations
pole / zero symmetry
large order / low order
Physical model synthesis
exciting.scm (hw#4)
complex resonance
closed / open reflection
impulsive excitation
self-sustained excitation
linear / non-linear (commutability)

Important unit conversions:

Homework #4

Create a resonator cutting a short (about 1 foot) piece of tube from the one provided in the ballroom (like the white one showed today in class).
Tap on the end of the tube and record the impulses obtained.
Save it in a soundfile tube.wav
Use the Scheme code seen today in class (for example, starting from the plucked string (pluck.scm), or clarinet.scm) to create a resonator.
The resonator must have the same fundamental frequency as the one of your tube.wav.
What is the length of the delay line used in your synthetic resonator? (justify your answer)
Save a screenshot with the Scheme code and a soundfile with your synthetic resonator.
When you are done, e-mail serafin@ccrma with the results.