![Page 1: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/1.jpg)
PHYSICS
FREQUENCY (HERTZ)
AMPLITUDE (DECIBELS)
PSYCHO
PITCH (MELS)
LOUDNESS (SONES)
![Page 2: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/2.jpg)
![Page 3: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/3.jpg)
PHYSICS
FREQUENCY (HERTZ)
AMPLITUDE (DECIBELS)
PSYCHO
PITCH (MELS)
LOUDNESS (SONES)
Human Psychoacoustics shows ‘tuning’for frequencies of speech
If a tree falls in the forest and no one is there to hear
it, will it make a sound?
![Page 4: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/4.jpg)
![Page 5: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/5.jpg)
Simple Sounds(A Pure Tone)
Air
What do ‘speakers’
do?
![Page 6: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/6.jpg)
Com
ple
x S
ou
nd
s
![Page 7: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/7.jpg)
Com
ple
x S
ou
nd
s
![Page 8: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/8.jpg)
Fourier Analysis Most Complex Sounds Are Composites of Multiple
‘Simple’ Frequencies Fundamentals and Harmonics
Sound Complexity: Perceived ‘psychologically’ as TIMBRE (sound quality). Timbre is a function of the number, intensity, and duration of harmonic frequencies associated with a complex sound
‘complex’ sound wave‘simple’ sound wave
![Page 9: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/9.jpg)
Fouri
er
Analy
sis
of
aC
om
ple
x S
ound
Wave
+ + + +=
Fundamental (pitch)
Harmonics (timbre)
Is there an easier way to
see this?
![Page 10: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/10.jpg)
Fourier Analysis
500 Hz
1000 Hz
1500 Hz
2000 Hz
2500 Hz
Trumpet
Time
kHz
0
1
2
3
4
Frequency Spectrogram(linear scale)
![Page 11: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/11.jpg)
Fourier Analysis
500 Hz
1000 Hz
Flute
Time
kHz
0
1
2
3
4
Frequency Spectrogram(linear scale)
Are You Ready For Some. . .
![Page 12: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/12.jpg)
+ + + + =
Fourier Synthesis: 5 values encode the waveform (high quality)
Digital (CD) Audio: 2 values encode the waveform (very low quality) 18 values encode the waveform (med quality)
Low sample rate Med sample rate
= or
Requires multi-voice (multi-frequency) synthesizerIn this example, a ‘5-voice’ synthesizer would be needed
![Page 13: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/13.jpg)
+ + + + =
Fourier Synthesis: Modeling an ‘acoustic’ instrument
+ + + + =
However, since each frequency is produced independently, harmonic frequencies can be
manipulated directly to create completely new timbres not possible with acoustic instruments: the birth of
techno! Amplitude modulation of high
freq harmonic
![Page 14: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/14.jpg)
Fourier Analysis
500 Hz
1000 Hz
1500 Hz
2000 Hz
2500 Hz
Synth
Time
kHz
0
1
2
3
4
Frequency Spectrogram
![Page 15: PHYSICS Frequency (Hertz) Amplitude (Decibels)](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813aeb550346895da35746/html5/thumbnails/15.jpg)
A E I O U
Guess who else does amplitude modulation of harmonics?
The ‘raw’ complex sound waves for each vowel sound
Fourier Analysis breaks each complex sound wave into individual frequency components