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  • Wave Fronts

    The shape or configurations of the component compressions and rarefactions as they diffuse through a medium.


    The dissipation of sound energy or weakening of wave trains as they travel through a medium.


    The bending of wave fronts as they pass through media having unequal or varying density.


    The spreading out of wave fronts into areas behind and around physical barriers. The filling-in of areas behind physical barriers that are blocked and not in a straight line from the sound source.


    The periodic reinforcement and cancellation of two wave fronts with frequencies closer together than 20Hz.

    Difference tones

    The periodic reinforcement and cancellation of two wave trains with frequencies further apart than 20Hz. May be perceived as a third tone.

    Summation tones

    Subjective tones produced by the ear that are perceived as the sum of two external frequencies. These are heard best when they occur near the middle of the audible frequency spectrum.

    Subjective Tones

    Tones that do not exist in the environment but by forcing parts of the ear into non-linear vibration, are created within the ear itself.


    The perceived phenomenon of multiple echoes mixing with the primary sound.


    The trapping of sound waves in fibrous or porous materials which weakens the wavefront by reflecting and diffusing sound energy.


    Preventing sound waves from traveling through physical barriers. This may be accomplished by various combinations of reflection, absorption, diffusion, or by creating a barrier that will not transmit vibration.

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