Impact of standing waves on human auditory perception of low-frequency direction

This paper studies the effect of room modal resonances on the localisation of very low-frequency sound sources. A subjective listening test is conducted with 20 participants in an anechoic chamber, where the listener must detect the direction of the sound source for pure sinusoids at 31.5, 50 and 80 Hz. A synthetic standing wave pattern modelling a room resonant effect is created with two additional sound sources located at the left and the right side of the listener. Results show that the perception of low-frequency direction is negatively impacted by the minimum pressure node of the standing wave, even when the standing wave has a relatively low level, whereas the maximum pressure node does not have as strong of an effect. The results of the experiment demonstrate that in the low-frequency spectrum, direction judgement is strongly impacted by room resonances. The localisation ability in this frequency range depends on the direction of the direct sound in comparison with the position of the standing wave, and the level difference between the direct sound and the standing wave.