Sound Source System for Investigating the Auditory Perception of Infrasound Accompanied by Audio Sound

To gather more basic knowledge about both infrasound-perception mechanisms and the annoyance caused by infrasound, it is important to investigate the influence of the interaction between infrasound and sound at frequencies inside the common audio frequency range (audio sound) on the auditory perception. This paper gives a detailed description of a newly developed sound source system allowing simultaneous monaural stimulation of listeners with infrasound and audio-sound stimuli in psychoacoustic experiments. The sound source system covers a frequency range between 4 Hz and 6000 Hz. It can generate infrasound stimuli and audio-sound stimuli up to at least 123 dB SPL and 80 dB SPL, respectively, with inaudible harmonic distortions. Likewise, during simultaneous generation of high-level infrasound and audio sound, residual unwanted modulation frequencies remain imperceptible, owing to special design features. It can be concluded that the sound source system is suitable for investigating the auditory perception of infrasound accompanied by audio sound.