This gives a sound source which sweeps in frequency, with constant amplitude, from 20.48KHz to 20Hz at the rate of one octave per 5 seconds.
You can use this to listen to the frequency response of your speakers for example. The sound should all have the same volume over the whole range of frequencies. Of course your ears have a frequency rolloff which cuts off all sounds higher than 10-20KHz (depending on your age, your ear damage due to listening to too lound sounds, your genetics, etc.) Any increases or decreases in volume of the sound indicate problems (resonances, etc) with your speaker at that frequency.

This uses HTML5 to play the sound. If your browser cannot handle HTML5, you can download the .wav file.
Note that converting to a compressed format (mp3 or ogg for example) is not a good idea as the distortions they introduce produces harmonics of the sound which can mask the frequency itself. Thus this is supplied only in .wav format.
Although the .wav format was a Microsoft invention, Internet Explorer apparently does not support .wav files in HTML5

Frequency Sweep wav file

Note that on my laptop, the soundcard produces a distortion so that even on the high frequencies which I cannot hear (above 10KHz) I hear a fast sort of warbling sound. This should not be there in a good soundcard. The actual signal is constant amplitude and gradually decreases in pitch.

Time ----Freq
0 ------20K
5 ------10K
20 ------1.25K
25 ------640
30 ------320
35 ------160
40 ------ 80
45 ------ 40
50 ------ 20

Copyright W Unruh 2014