Signals and Sounds

This demo illustrates how signals with different frequency components look and sound.

Click on the signal to hear the tone.

 Signal Waveform and Spectrum


 This is a pure tone arising from a sinusoid. Synthetic music can be made by concatenating sine waves of different frequencies. More on this.

 This should sound the same as the pure sine wave since your ear would not pick up a DC bias. If it doesn't sound the same, your speaker is probably saturating causing the singal to clip.

 This adds a harmonic to the tone. It should sound richer.

 This adds a lot of harmonics of equal strength. You should hear the additional high frequency content when compared to the previous example.

 This should have slightly lower frequency content than the previous example due to the decreasing strength of the higher harmonics. It sounds a little less shrill.

 This has a lot of frequency content, sounds more like a buzzer!

 This is the result of a high frequency sinusoid (usually called the carrier signal) multiplying a low frequency sinusoid. The high frequency singal is the tone that you hear. The low frequency signal modulates the amplitude of the tone, thereby affecting its loudness in a sinusoidal pattern.

 This chirp signal is essentially a sinusoid with a frequency that is increasing over time. You can hear the increasein pitch.

These figures and wav files were generated using soundex.m.