### sound:

Knock
* are blows
  - bumps
  - criticism
  - misfortune
* is sound

Murmur
* Many murmurs are organic indicating valvular defects or other abnormalities within the heart.
* Some murmurs occur even though the heart and blood vessels are completely normal.
* are extra sounds heard over the heart and are associated with eddies and flow turbulence.
* is bands.

### sound | murmur:

Systolic murmur
* is murmur
* occur when the heart is contracting.

Musical sound
* Some musical sounds can cause changes in metabolism.
* are produced by regular vibrations.
* have a much broader bandwidth than speech
  - an experienced loudness and pitch
  - very powerful influence on human mind
* is one which is pleasing to the ear.

Natural sound
* Most natural sound occurs within ranges.
* Some natural sound occurs in parks.
* are a mixture of high and low pitch frequencies
  - unadorned production sounds
* is the result of a stream of continuous changes of vibrations in the atmosphere.

### sound:

Noise
* Most noise is associated with the vibrations of a structure, or of surrounding structures.
* affects hearing and can result in several adverse physiological and psychological effects
  - human behavior
  - millions of people worldwide on a daily basis, especially children
  - people in several ways, from nature cause noise to artificial noise
* appears as small, random variations in brightness or color.
* are sounds that someone or something makes.
* can damage hearing, too.
* carries many properties with it including the number, size and speed of vehicles.
* causes stress, and stress leading cause of illness and suicide.
* comes from the Latin word nausea, originally meaning seasickness.
* consists of all unwanted sound - sound that is loud, unpleasant or unexpected.
* depends on vehicle design, age, maintenance, operating speeds and track conditions.
* destroys many noise-sensing cells in the inner ear that no hearing aid can replace.
* exists in every area, where some sorts of energy of any kind occur.
* generated by an external source can often create disruption in electronic circuits
  - tractors, harvesters, chain saws, and other equipment can cause hearing loss
* interferes with sleep
  - speech communication
* is combination of intake and mechanical
  - cries
  - garbage perceptible to the ear
  - garbage, and it particularly insidious form of garbage
* is in general an irregular vibration in the air
  - pairwise steps due to the subtraction of successive pairs of frames
  - inherent in a telephone system and can have many sources
  - less noticeable when no one part of the audible spectrum is apparently dominant
* is located in big cities
  - carnivals
  - casinos
  - classrooms
  - concerts
  - crowds
  - factories
  - streets
  - transmissions
  - work
* is present both in the environment and in the sensory system of the observer
  - in all analog devices, but the digital domain is principally noise free
  - trouble
* is used for alerting
  - warning
  - usually the result of unavoidable random electron motion in electronic devices
  - waves
* limits all forms of communication, including vision.
* means life, silence means death.
* negatively affects learning and behavior.
* often scare animals unnecessarily.
* plays a crucial role in communication systems.
* produced by animals and animal care activities is inherent in animal facilities.
* raises blood pressure without impairing auditory sensitivity.
* refer to the signal level and noise level in dBm.
* refers to disturbances which take place in the communication process
  - natural noises such as static
  - unwanted electromagnetic waveforms which corrupt a message signal
* travels great distances across lakes.