Ear Protective DevicesHearing Loss, Noise-InducedNoise, OccupationalNoiseSignal-To-Noise RatioAuditory ThresholdAircraftPerceptual MaskingArtifactsAcoustic StimulationSound SpectrographyStochastic ProcessesRailroadsAudiometryAlgorithmsPsychoacousticsSpeech PerceptionAudiometry, Pure-ToneAuditory PerceptionSignal Detection, PsychologicalHearingSensory ThresholdsLoudness PerceptionMotor VehiclesComputer SimulationSpeech IntelligibilityAutomobiles