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Speech Science
01 Frequency
Term | Definition |
---|---|
Hierarchy of Speech Acts | 1. Neural Signals 2.Muscular Contractions 3. Structural Movement(lips, jaw, tongue, velum, vocal folds) 4. Areodynamic Events (result of structural movement- friction sounds, building up & releasing of pressure) 5.Acoustic Consequences 6.Speech |
In order to have sound, you must have | 1. Something put into vibration 2. Something to conduct (i.e., carry or transmit) the sound vibrations |
In order to have vibration | Something with elastic properties must be put into motion |
Elasticity | -the tendency for an object to return to its normal resting state. |
Inertia | -the tendency for a body at rest to remain at rest, or a body in motion to remain in motion. |
Conductors | -conduct sound well |
Insulators | -don’t conduct sound well |
How Sound is Conducted | Compressions & Rarefactions |
Degree of max compression | 90° |
Degree of max rarefaction | 270° |
2 tones are presented, with identical frequency and intensity. However, they are 180 degrees out of phase. What happens? | cancellation |
2 tones are presented, with identical frequency and intensity, and the exact phase relationship. What would happen? | A single tonewith increased amplitude |
Amplitude | -The maximum displacement during a cycle of vibration -The point of maximum compression |
Sound is conducted through a medium by | The traveling of the disturbance. Air particles do NOT move a great distance, just enough to disturb the next air particle and so forth. |
Rarefraction | point of stretch |
Trough | valley that's the point of maximum rarefaction |
Amplitude | peaks are point of maximum compression |
relationship pf amplitude/compression and intensity. | The greater the compression/amplitudue, the greater the intensity. |
We perceive intensity as | loudness |
Damping | The gradual decrease in the amplitude of vibration over time |
Psychological perception of frequency | Pitch |
Psychological perception of Intensity | Loudness |
3 Physical Properties of Sound | -Frequency (# of cycles, pitch)-- measured in Hertz (Hz) -Intensity (height of wave, amplitude)-- measured in decibels (dB) -Duration-- measured in milliseconds (ms) |
Frequency is determined by what? | -The number of complete cycles occurring during one second. -The more cycles that occur in 1 sec the higher the frequency and vice versa. |
In order to have a perceptible pitch, a frequency that you can hear, there has to be... | -Repetition -each cycle must occur and reoccur at the same rate |
periodic wave | A sound wave that repeats itself at regular intervals |
aperiodic wave | -A sound wave that is non-repetitive, has a different rate for each cycle -No specific frequency can be assigned to -it has no perceptible pitch -it is random noise |
If a tone has 1000 cycles in one second, how long does it take to complete one cycle? or what is it's period | -each cycle takes 1/1000 of a second |
How long does it take to complete one cycle of a 250 Hz tone? or what is it's period | -1/250 of a second |
period | -The length of time it takes for a tone to complete one cycle of vibration |
tones with higher frequencies have what kind of periods. | shorter |
How to Convert to milliseconds | pull decimal to right 3 places. |
What is the period of a 1000 Hz tone? | =1/1000 sec =0.001 sec =1 ms |
What is the period of a 2000 Hz tone | =1/2000 =0.0005 sec =0.5 ms |
What is the period of a 250 Hz tone? | =1/250 sec =0.004 sec =4ms |
What is the period of a 500 Hz tone? | =1/500 sec =0.002 sec =2ms |
What is the frequency of a tone that has a period of 50 ms? | decimal moves left 3 times = 0.050 sec = 1/0.05 = 20 Hz |
What is the frequency of a tone that has a period of 5 ms? | 5 ms= .005 sec 1/.005= 200hz |
What is the frequency of a tone that has a period of 20 ms? | =0.020 sec =1/.02 =50 Hz |
How to calculate frequency with a graph | -must know the time per divion -count how many seconds it takes to complete 1 cycle -Ex:2ms to complete one cycle 2ms= .002 sec 1/.002 =500 Hz (frequency) |