Assignment 1, Weeks of Feb. 1 and 8: Due: Tues. Feb. 16

Building a Comb Filter and Using it

• Reading: chapters 1-3 of the text (phasors, strings, sampling and quantizing)
  
  
• In the lab: First, there are several pieces of software you should learn to use. They are
  
  
  
  
  • ein - You can also read an article in postscript or in pdf format.
    
    
  • Other tools and essential things to setup and know.
  
  
  
• Then, try the following. Note: We realize that your backgrounds are varied and that some students will not be able to do all the math for the two problems -- don't worry about it, do as much as you can, and we'll see where we stand when we discuss this assignment on Feb. 16.
  
  
  
  1. Generate a few sine waves with arbitrary pitch. Can you vary the pitch during a note?
     
     
  2. Do Problem 1.9 (chirp signal) and implement in ein. What do you observe? Explain.
     
     
  3. Do 1.13 (instantaneous frequency of a beat) and implement in ein. What do you observe? Explain.
     
     
  4. Implement the simplest possible comb filter in ein. This will be discussed in class. Measure its pitch. Create a scale by varying the loop length. How good a scale can you get in the octave beginning with C8? With C9? (This may be easier to do in Cmix/einwrap.)
     
     
  5. Download some (non-Microsoft) soundfiles from the net. Convert them to 16-bit, 22050hz snd files. Create a Cmix instrument from your comb ein script. Write a short composition mixing one or more of these soundfiles through this filter in different ways.
  
  
  
• What to submit:
  
  
  • On paper, your theoretical work on Problems 1.9 and 1.13.
    
    
  • In the directory /var/cs325/_your_user_name_, einscripts and soundfiles for the parts above.