the material around the object in which the vibrations are transmitted through
When an object vibrates it...?
It is going to change the pressure in the medium around it and is going to change the pressure in the waves.
How far do molecules and waves go in the medium?
Molecules don't go very far but waves go far until they are obstructered by something else
Sound Waves-
- travel faster through denser medium(faster through water than air)
- Sound Waves we hear are jus fluctuations in air pressure over time
Amplitude
the magnitude of pressure change. The diff between the highest and lowest pressure areas
Frequency
the number of times per second that the pattern of pressure changes, repeats
-measured in Hertz=Hz
1 Hz=
1 cycle per second
Cycle is movement movement all the way up and down
Perceptual qualities of Amplitude
associated with the perceptual quality of loudness.
as amplitude inc. loudness inc.
Perceptual Qualities of Frequency
associated with pitch
low cycles per second= low pitch
high cycles per second= high pitch
Audible Frequencies
human hearing uses limited range of frequencies present in the environment.
Is similar to visible light
We can hear from about 20 to 20,000 Hz
Sensitivity to sound frequency is species dependent(dog whistle)
Audible Intensities
Very wide range
Intensity measured in decibels (dB)
Small decibel increase corresponds with large physical range
Sine Wave
(Simplest kind of Sound Wave)
Also known as pure tone
The air pressure changes continuously at the same frequency
2 Characteristics of Sine Wave
Period-time taken for one complete cycle
There are 360 degrees across one period
Phase-relative position of 2 or more sine waves
Not very common everyday. Can be found in a tuning fork and hearing tests. Flutes can almost produce sine waves.
Complex Tones
Sound wave consisting of more than one sinusoidal component of different frequencies
Pressure changes are not the same throughout the whole cycle
All sounds can be describes as combinations of...?
Sine Waves
Fourier Analysis
allows us to break down complex tones into their component/relative freaquencies (can be broken down into a high frequency and low frequency tones that when put together equal the complex tone)
Complex Tones..
Spectrum?
a representation of the relative energy or amplitude, present in each frequency that makes up that complex tone.
Most complex tones have a Fundamental Frequency(FO)-
the lowest frequency component of a complex tone
Harmonic Spectrum
Energy at integer multiples of the Fundamental frequency
Is typically created by a simple vibrating source such as a guitar string or a sex reed.
In Harmonic Spectrum each frequency is called....?
harmonic
The shape of the spectra changes as instruments play the same notes