Quiz 6 Flashcards
Monday October 21 - Wednesday October 23
What is the source?
The glottal source, or noise generated at a constriction in the vocal tract
What is the filter?
The supra-laryngeal cavities
What is source filter theory?
Believes that all sound is a product of sound being filtered
What are harmonics in relation to the source?
A harmonic is simply a wave (component frequency) that is available in the source signal
Speech signals can have infinite number of harmonics
What are the 3 concepts of filtering?
High pass filter
Low pass filter
Band pass filter
What is a pass band?
A filter with a lower and an upper cut off
What is the bandwidth?
The frequencies that make up the pass band
What is a high pass filter?
A filter where any value above the cutoff can pass
What is a low pass filter?
A filter where any value below the cutoff can pass
How do formants relate to filters?
Our vocal tract acts as a series of band-pass filters
The centre frequencies of those filters are the formants we see
What is resonance calculation for an open tube?
λn = 2L/n
What is resonance calculation for a tube that is closed at one end?
λn = 4L/n (n must be odd)
λn = 4L/(2n-1)
2n-1 ensures that it is always an odd number
What type of tube does our vocal tract resemble?
Closed at one end (larynx) open at the other
What are standing waves?
Waves that will sustain if you stimulate a column of air with different sine waves
What does boundary condition refer to?
The rules that must be followed to allow certain waves to “stand” in a tube
What are the boundary conditions?
If a tube allows a node at a certain end (closed end) a sustained wave must have a node at that end
If a tube allows an antinode at a certain end (open end) a sustained wave must have an antinode at that end
Other waves will die
