Audacity is an open source sound recorder and audio editing application. Here's how you can install it in Ubuntu 13.10.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each.
sudo add-apt-repository ppa:audacity-team/daily
sudo apt-get update
sudo apt-get install audacity
Audacity free open-source, easy-to-use, sound recorder, multi-track audio editor and cross-platform available for Linux, Windows and Mac OS X. This program is translated into many languages and it's main functionality includes: live audio recording through microphone or mixer, convert tapes and records into digital recordings or CDs, support sound editing (WAV, AIFF, FLAC, MP2, MP3 or Ogg Vorbis), Change the speed or pitch of a recording, and Cut, copy, splice or mix sounds together.More at Noobs Lab
Additional resources for Audacity