a-weighting acoustic impedance acoustics american national standards institute amplitude atmosphere audio bit depth audio frequency audio signal processing auditory imagery automobile bird bird vocalization characteristic impedance communication compression decibel density diffraction doppler effect drum ear earth earthquake elastic modulus equilibrium fire frequency frog gas hearing aid hertz human hydrosphere international electrotechnical commission jackhammer jet engine krakatoa liquid longitudinal wave loudspeaker mammal mel scale microphone music musical instrument navigation noise note ocean surface wave parametric array particle acceleration particle displacement particle velocity particle velocity level periodicity phon physical compression polarization predation pressure psychoacoustics radio rain rarefaction resonance reverberation rijke tube root mean square sense shear stress sine wave solid sonar sone sonic weaponry sound energy density sound energy flux sound intensity sound intensity level sound localization sound power sound power level sound pressure soundproofing species speed of sound state of matter surface telephone temperature threshold of pain timbre transmission medium transverse wave ultrasound vacuum velocity vibration wave vector wavelength wikibooks wikiquote wind