Experiment 5:Music Introduction The tones produced by periodic waveforms are example of complex periodic waves.Musicians generally use three terms to describe a musical tone-pitch,loudness,and quality.Pitch refers to the frequency of vibration of the tone.A higher frequency produces a higher pitch.Loudness refers to the amplitude of the sound wave,or to be more precise,to our subjective sense of that amplitude. Quality is a more complicated phenomena.Two instruments,such as a clarinet and a piano,can produce tones of the same pitch and loudness,yet the two tones will be quite distinct.The reason for this is that virtually all musical tones are made up of a relatively high amplitude fundamental frequency,which determines the pitch,and a variety of higher harmonies at lower amplitudes, which determine the quality of the tone.It is these higher frequencies and their relative amplitudes that let us distinguish the same tone as it is played by different instruments. In this experiment,you will examine the relationships between wave shape,as seen on the oscilloscope,and the sound produced when the wave drives a speaker. Procedure 1.Hook up the Fourier Synthesizer to your oscilloscope as described in the SETUP section. 2.Connect a speaker (82 input impedance)between the 89 OUTPUT connectors of the Synthesizer. 3.Turn on the Synthesizer and switch the first fundamental into the summing amplifier.Adjust the amplitude of the wave until it is a convenient size on the oscilloscope.You can adjust the volume of the sound with the GAIN knob on the Synthesizer. 4.Switch the waveform to a square wave and readjust the amplitude to equal that of the sine wave.Now switch to a triangular wave.Switch back and forth between these three waveforms. Describe any differences you notice in the pitch,loudness,and quality of the three tones.Try to relate the differences you hear to differences in the waveforms you see on the oscilloscope. 5.Switch the waveform of the fundamental back to a sine wave.Switch in the 2nd harmonic Vary its amplitude and note the effects on the scope and on the sound.Set the amplitude of the fundamental and the 2nd harmonic to the same level.Does one tone or the other seen to dominate?(i.e.do you hear a single tone that varies in quality as you adjust the amplitude of either harmonic,or do you hear two tones of different pitch?)Change the phase of the 2nd harmonic.Does changing the phase affect the sound? 6.Switch in higher harmonic.Vary the amplitude and again,try to relate the pitch,loudness,and quality of the sound to the waveform you sec on the oscilloscope. 7.The table below show a the harmonic make up of the tones from a violin,a clarinet,and a piano.I'ry each tone.Adjust each individual harmonic to the proper amplitude,then switch them all into the summing amplifier to produce the tone. NOTE:The tones produced by the Fourier Synthesizer will not sound exactly like the chosen musical instrument.Several other factors play a role.One factor is that higher harmonic may be needed to more closely produce the tone.Another is that most musical instruments do not produce a continuous tone such as those of the synthesizer.The shape of the waveform produced by an instrument varies with time for each note.These variations are not reproduced by the Synthesizer. 66 Experiment 5: Music Introduction The tones produced by periodic waveforms are example of complex periodic waves. Musicians generally use three terms to describe a musical tone-pitch, loudness, and quality. Pitch refers to the frequency of vibration of the tone. A higher frequency produces a higher pitch. Loudness refers to the amplitude of the sound wave, or to be more precise, to our subjective sense of that amplitude. Quality is a more complicated phenomena. Two instruments, such as a clarinet and a piano, can produce tones of the same pitch and loudness, yet the two tones will be quite distinct. The reason for this is that virtually all musical tones are made up of a relatively high amplitude fundamental frequency, which determines the pitch, and a variety of higher harmonies at lower amplitudes, which determine the quality of the tone. It is these higher frequencies and their relative amplitudes that let us distinguish the same tone as it is played by different instruments. In this experiment, you will examine the relationships between wave shape, as seen on the oscilloscope, and the sound produced when the wave drives a speaker. Procedure 1. Hook up the Fourier Synthesizer to your oscilloscope as described in the SETUP section. 2. Connect a speaker (8Ω input impedance) between the 8Ω OUTPUT connectors of the Synthesizer. 3. Turn on the Synthesizer and switch the first fundamental into the summing amplifier. Adjust the amplitude of the wave until it is a convenient size on the oscilloscope. You can adjust the volume of the sound with the GAIN knob on the Synthesizer. 4. Switch the waveform to a square wave and readjust the amplitude to equal that of the sine wave. Now switch to a triangular wave. Switch back and forth between these three waveforms. Describe any differences you notice in the pitch, loudness, and quality of the three tones. Try to relate the differences you hear to differences in the waveforms you see on the oscilloscope. 5. Switch the waveform of the fundamental back to a sine wave. Switch in the 2nd harmonic. Vary its amplitude and note the effects on the scope and on the sound. Set the amplitude of the fundamental and the 2nd harmonic to the same level. Does one tone or the other seen to dominate? (i.e. do you hear a single tone that varies in quality as you adjust the amplitude of either harmonic, or do you hear two tones of different pitch?) Change the phase of the 2nd harmonic. Does changing the phase affect the sound? 6. Switch in higher harmonic. Vary the amplitude and again, try to relate the pitch, loudness, and quality of the sound to the waveform you sec on the oscilloscope. 7. The table below show a the harmonic make up of the tones from a violin, a clarinet, and a piano. 1'ry each tone. Adjust each individual harmonic to the proper amplitude, then switch them all into the summing amplifier to produce the tone. NOTE: The tones produced by the Fourier Synthesizer will not sound exactly like the chosen musical instrument. Several other factors play a role. One factor is that higher harmonic may be needed to more closely produce the tone. Another is that most musical instruments do not produce a continuous tone such as those of the synthesizer. The shape of the waveform produced by an instrument varies with time for each note. These variations are not reproduced by the Synthesizer