Lecture 3-Amplitude, Pitch, Frequency & Phase Flashcards
How does amplitude affect how the sound pressure is acting on air particles?
The greater the sound pressure (or intensity), the louder the sound.
How does the frequency effect how fast the air particles are vibrating back and forth?
The greater the frequency the higher the pitch.
How does phase effect when the vibrations reach our ears relative to other sound sources?
Sounds from different sources can add together to create louder sounds or can completely cancel each other out.
How do we measure vibration?
Number of times the air particles move back and forth in one second (cycles per second or Hz).
What is the equation for frequency?
Frequency (in cycles/sec)= 1/periodic time=1/T
What does phase do in waveform?
Indicates where on a cycle a waveform is, we divide each cycle into 360degrees.
What is constructive interference?
When sound waves double the level.
What is destructive interference?
Phase cancellation, sound waves cancel each other out.
How can all real-world sounds be expressed?
A summation of pure tones.
What are the two ways of visualising audio signals?
Time domain (amplitude fluctuations over time). The frequency domain (the frequency content).
Why is it difficult to visualise audio signals in time domain?
Difficult to tell what frequencies make up the sound, but we can see how the signal evolves over time.
Why is it difficult to visualise audio signals in frequency domain?
We lose information about the timing of the signal but we do know what frequencies are in it (spectral content).
What do spectrograms do?
Useful plots as they tell us the temporal and frequency information simultaneously
