15-110 Summer 2017

Lab 8

Warning: before listening to any sound files through ear buds turn down the sound.


This lab is intended to develop your understanding of encodings and how to exploit them. Specifically, you will work with a sound encoding, but the ideas are more widely applicable. Warning: If you don't use the linux server for this lab you will have to be able listen to .wav files on your personal machine. (The Chrome browser will play them for you, for instance.)

When you are done, you should be able to do the following:

  1. Explain in terms of sampling and sampling rate, how splicing two lists of numbers together can create a longer sound out of two shorter ones.
  2. Choose a number to speed up or slow down a sound by a predictable amount and explain your reasoning in terms of samples and sampling rate.


  1. composer.py
  2. speed.py

Place these files in a lab8 folder. Before leaving lab, zip up the lab8 folder and hand the zip file in.

Python Audio Information

This lab uses module snd110 which is in snd110.py. Download this file into your working folder.

Part 1 - Sounds and Songs

1.1 - TA Demonstration

1.2 - Class Activity

Part 2 - Manipulating Sounds

2.1 TA Demonstration

2.2 Student Activity