Interactive soundscape augmentation by natural sounds in a noise polluted urban park

Inappropriate sound environments are able to strongly deteriorate the user experience in parks. A possible remediation is adding positively perceived sounds. The case of an urban park, fully surrounded by busy roads, was studied to explore the potential of adding natural sounds in an interactive way. With a smartphone app, recruited users (N = 165) were allowed to mix in a combination of eight types of natural sounds, played back by a hidden loudspeaker, until their personally optimized soundscape was composed. These preferred soundscapes were then evaluated by other participants. A questionnaire showed that these compositions are able to improve the general appreciation of the auditive environment, especially for park visitors that rated the reference situation as poor. Road traffic noise, the dominant sound source in the park under study, was heard to a much lesser extent, showing the masking potential of the augmented natural soundscapes. Most people prefer a balanced combination of various types of (natural) sounds, in which songbirds and house sparrows were prominent. There was consistency among the participants to optimize the signal-to-noise ratio of the added natural sounds in the frequency range between 2.5 kHz and 8 kHz. So without the common and most often visually intruding noise abatements solutions, interactively augmented soundscapes can improve the sonic environment in noise polluted parks. More in general, the current ICT-based approach can be considered as an efficient methodology to improve the perception of urban public spaces.