Quiz #2 Flashcards
True or false:
the lower the fundamental frequency is the more frequencies will appear in the harmonic series?
True
What is the equation for a wavelength?
See physical flashcards
Can we measure a wavelength from any point in one cycle to the same point in the next cycle?
Yes
Frequency is directly related to…?
Pitch
What is harmonics?
All the tones created by complex vibrations
What is periodic?
The pattern of vibration repeating itself
True or false:
a simple sine wave is always periodic?
True
What is a complex wave?
Multiple frequencies
What can young and healthy ears detect vibrations as low as and as high as?
20 Hz and 20,000 Hz.
Speech is heard at 100 Hz to 5000 Hz
What does a spectral plot give us?
Amplitude on the Y axis and frequency on the X axis
What are the physical properties of Sound?
- Time
- Intensity/amplitude
- Frequency
- period
- Velocity
How do you calculate the harmonic series when the sound is 200 Hz and the fundamental frequency equals 200
first harmonic = 200x1= 200Hz
second harmonic 200×2 = 400 Hz
third harmonic is 200×3 = 600 Hz
And so on
How can a periodic wave be distinguished from an aperiodic wave?
Based on the mathematical relationships among the frequencies of their components. Aperiodic won’t have a pattern or a mathematical relationship
What is the fundamental frequency?
Lowest frequency there is in a waveform/complex tone
What is a phase relationship?
Where waveforms meet
What is amplitude measured in?
Decibels (dB)
When would you expect to see higher frequencies that are farther apart?
Whenever you start with a higher fundamental frequency
For a child with a high pitch will they have more frequencies in the harmonic series or less
Less. Fewer frequencies and are farther apart because you start with a higher fundamental freq.
Are intensity and loudness linearly related?
No
What are boundary behaviors?
Sound bouncing off the object and sound returning
True or false:
as frequencies get higher, it takes a larger change in Hz to cause a change in sensation of Pitch?
True
Can a simple tone/waveform be aperiodic?
No
What is always the first harmonic in the series?
Fundamental frequency
Does a harmonic need to include all the harmonic series?
No, it can skip, but it must be a mathematical relationship between odds and evens
What is a constructive pressure wave?
When crest meets crest or troughs meet trough
In phase and 90% out of phase
What are the perceptual properties of sound?
- Loudness
- Pitch
What is pitch measured?
Mels
What is Hz measured in?
Cycles per second
What is a complex wave?
Different frequencies
What is “in phase”?
When troughs and peaks of the waveform are in the same wave
What is reverberate?
Sound bounces back and forth. Echo
What is a wave pattern of vibrations, no matter how complex and how often it repeats itself?
Complex periodic soundwave
What is a destructive pressure wave?
When crest meets trough (silence)
If the vibration of a wave is random and has no repeatable pattern it is…?
A complex aperiodic soundwave
Sound = tone Wave = how it travels Waveforms = when we draw it out
.
Is loudness perceptual or physical?
Perceptual
It is perceived that if the intensity is higher than it is louder
What type of tone will you get with two pure tones of the same frequency?
Pure tone/sine wave
What are waves characteristics?
- Boundary behaviors
- Interference patterns
- pure tones
What type of tone will you get with two pure tones of different frequencies?
A complex tone
What is the velocity for meters?
344 m/seconds
What is velocity measured in feet?
1130 feet/second
What is the resulting wave of two signals of the same frequency and 180° out of phase?
The result is silence. Each particle has been subjected to equal forces acting in opposing directions
Proper acoustic design helps with what?
Sound travel through space ( e.g. Concert halls)
What is the Fourier analysis?
A different sort of displaying called a spectral plot. That allows us to indicate the frequency and amplitude of each harmonic in a complex periodic wave
What two factors does wavelength depends upon?
- The velocity of a soundwave (c)
- The frequency of the vibration (f)
See the equation for wavelength
What is a Pure tone?
- A single periodic frequency vibrating in simple harmonic motion/creates a sign wave.
- A vibration that repeats itself at a constant number of cycles per second.
- It is unnatural
What is the resulting wave of two signals of the same frequency for “in phase”, 90% out of phase and 180% out of phase?
They will have an amplitude equal to the sum of the amplitudes of each wave
What is considered noise?
An aperiodic complex tone of two or more components frequencies not harmonically related. No fundamental frequency. No harmonics.
What does a wavelength represent?
The velocity over the frequency. It represents one cycle.
What is aperiodic?
No repeatable patterns of vibration in the soundwave
We can determine the fundamental frequency of the sound the waveform represents by…?
- Counting the number of times it’s patterned is repeated per cycle
- We can then calculate the frequency of the individual harmonics
- We cannot discover the amplitudes of individual harmonics
What is pitch?
- a sensation
- a perception by listener when frequencies change
What is a harmonic series?
Each tone created in a complex vibration is called “harmonic”. The whole set of tones is called harmonic series
What are interference patterns?
- Signals of the same frequency can interfere with each other
- Same frequency, two sources or signal is reflected from a barrier and competes with itself
Loudness is directly related to what?
Amplitude/intensity
What is loudness measured by?
Phones and sones
The amplitude of the vibration is…?
The extent of particle displacement, which is an indication of the intensity or power of the sound
What is a sine wave?
A pure tone. Single frequency
What are the three graphic representations for analysis of sound?
- Waveform
- Spectral plot
- Spectrogram
Low-frequency wave has more or less vibratory cycles/second?
More
Do lower frequencies have a bigger or smaller wavelength?
Bigger
High-frequency waves have more or less vibratory cycles per second?
Less
Higher frequency sounds have shorter or longer wavelength
Shorter/smaller
