A recording of a single violin tone is analyzed. The pitch is 500 Hz which is approximately B above concert A. A recording of a single trumpet tone of the same pitch is also analyzed. The program recognizes the following commands.
|Select the violin.
|Select the trumpet.
|Play the recorded musical tone.
|Play the first harmonic of the recorded musical tone. (The overtones were stripped from the tone, leaving only the first harmonic. Note that the violin and trumpet sound the same without the harmonics. It's the harmonics that cause them to sound differently.
|Display a segment of the sound wave from the tone. Note that the wave form repeats every 2 ms. This is the period of the first harmonic of the wave. The frequency f=1/(2ms)=500Hz of the first harmonic is called the pitch of the tone. Note that the wave for the trumpet contains fewer high-frequency oscillations than that for the violin. The high-harmonic content of the trumpet tone is not as intense as that of the violin tone.
|Display the spectrum of the tone. Peaks occur at multiples of 500 Hz and arise from the harmonics contained in the tone. Note that the vertical scale is dB which is logarithmic in intensity. The noise is about 60 dB below the tone which is about a factor of 100,000 in intensity. Also note that the scale for the trumpet is extended to -10 dB. The higher harmonics have less intensity in the trumpet tone than in the violin tone.
|Display the wave and play the tone of each harmonic in the tone. Press next to display the next harmonic and add it to the tone. Press add to add it to the wave. After 16 harmonics have been added together, we obtain the wave for the complete tone. (Higher harmonics have negligible contribution to the wave form.)