Absolute and Relative Measure of Acoustic Power
The rate at which sound energy is transferred through a medium.
What is Acoustic Power?
Relationship between a decibel and a bel
What is a decibel is 10 times a bel?
What is 62.5 Hz?
Defines the starting phase as a function of frequency.
What is Phase Spectrum?
Has an absence of periodicity, so it is impossible to know what the wave will look like from interval of time to another.
What is Aperiodic Wave?
The unit measure of power or acoustic power
What is watt?
1 dB converted to bels
What is .1 bels?
Complex waves and all other sound waves that are not sinusoidal are composed of a series of simple sinusoids that can differ in amplitude, frequency and phase.
What is Fourier's Theorem?
An octave always refers to a frequency ratio not to a frequency difference. T/F
What is True?
Two examples of aperiodic sounds
What is speech sounds ("sh" "s" "th" "f") or aircraft noises, cars or speedboats?
We generally refer to the pressure associated with a sound wave rather than its acoustic power or intensity. T/F
What is True?
Intensity (I) is proportional to pressure squared. T/F
What is True?
The harmonics are numbered consecutively from highest to lowest frequency. T/F
What is false?
The location of each vertical line along the horizontal axis indicates the frequency of that component and the height of each line is proportional to its relative amplitude.
What is amplitude spectrum?
An aperiodic waveform with equal energy within any frequency band 1 Hz wide and with all phases present in random array.
What is white noise?
Absolute power in one sound wave is compared with the absolute power in another (reference) wave
What is relative measure of power?
Not the absence of sound. The pressure in question equals the reference pressure.
What is 0 dB SPL?
Three important characteristics of both periodic and aperiodic sound waves.
What is the waveform in the time domain, the amplitude spectrum in the frequency domain, and the phase spectrum in the frequency domain?
A complex periodic wave with energy at all odd and even integer multiples of the fundamental frequency.
What is Sawtooth Wave?
Equal energy at all frequencies is not a requirement for all aperiodic waveforms. T/F
What is true?
Ix = 10^- 5 watt / m2, and if Ir = 10^- 10 watt / m2
The absolute intensity, Ix is
The relative intensity is
The level of intensity in bels is
What is 10^- 5 watt / m2, 10^5 and 5 bels?
The difference between log equation for sound pressure and intensity.
What is 20 log(P1/P2) vs 10 log(I1/I2)?
100 Hz, 200 Hz, 300 Hz, 400 Hz
The 2nd harmonic is
The 2nd partial is
The 2nd overtone is
What is 200 Hz, 200 Hz, and 300 Hz?
The difference between a triangular wave from a square wave.
What is the slope of the spectral envelope of a triangular wave is twice as steep,–12 dB per octave?
Spectral envelope slope of white noise
What is 0 dB per octave?