Homework #2: Delay, Feedback, Moving Average, Polyphony

Due date: 2008.10.22 11:59:59pm (or thereabout), Wednesday.

create a program that is capable of real-time audio input/output (e.g., use the skeleton framework from HW1)
craft the framework for a delay by implementing a circular buffer:
- think about how to implement a delay element that delays the input signal by some integer number of samples
- think about how to implement this efficiently, without shifting all the elements for each sample
  - an array of samples
  - two pointers: one for reading, and another for writing, initialize them
  - advance the pointers accordingly, writing and reading into the corresponding locations via the pointers
- test with with the microphone (with varying delay lengths)
now add feedback, with some attenuation factor (<1)
- take each output sample of the delay, multiply it by attenuation factor (<1), and add it into the input
- test with the microphone (with varying delay lengths)
next, modify the feedback by adding a 2-point moving average filter into the feedback loop: simply average the current output sample with the previous output sample.
final test: on demand (e.g., via console input), load the array with white noise, and let it run

use the framework above, algorithmically generate and/or play a sonic/musical statement
record it turn it in

have fun with it!!!
your code should compile and run on the CCRMA machines
comment your code!
choose your own coding conventions - but be consistent
you are welcome to work together, but you must do/turn in your own work (you'll likely get more out of it this way)
some considerations:
- how to organize the code for the various types of signals?
- how much error-checking and error-reporting on the command line arguments?

turn in all files by putting them in your Library/Web/256/hw2/ directory, and concise online documentation + readme

1) source code to the project (*.h, *.cpp, *.c makefile, etc.)
2) online page for your project (should be viewable at http://ccrma.stanford.edu/~YOURID/256/hw2/). It should include:
- links to your files of various kinds
- instructions on building the project (for example, anyone in the class should be able to download
- a short README text section that:
  - conveys your ideas/comments in constructing each program
  - describes any difficulties you encountered in the process
  - lists any collaborators
3) email Ge with the link to your web page, as a confirmation that you are submitting the assignment

256-fall-2008/hw2