Recording Audio - in two ways
There are two ways you will probably want to record audio on your computer:
1) With a microphone. Either one built into your machine or a better, external mic, one that connects to the computer usually through a USB or audio in port, and coming from the mic directly or from a pre-amp that the mic plugs into; this depends on the type of mic. Unless you are familiar with audio mics, preamps, etc., or need very accurate recordings, it will pay to obtain a mic intended for direct computer input. Another option is a standalone mic-recorder that writes files to a flash drive for uploading into your computer. If relatively poor quality is all that is needed, this is often the case, you can use the mic built into the machine.
2) By streaming audio recording. That is, direct recording of sound data that the computer is generating, as from playback of another audio file or CD, or sound generated by audio software such as any of the packages mentioned in Software or Falstad applets, and MAX patches . (Some of these packages have an option of writing a sound file directly to disk, and you won't need to separately capture the sound). Note that by capture, we mean direct electronic capture, not using a mic to record the computer sound coming out of loudspeakers!
Examples of direct streaming capture software include Wire Tap Studio for the Mac, www.ambrosiasw.com/utilities/wiretap/, and Streaming Audio Recorder for the PC (free), http://www.apowersoft.com/, and SoundTap (both platforms), http://www.nch.com.au/soundtap/index.html.