Reduced reproduction levels of outdoor soundscapes are deemed appropriate – even after real-world exposure

Laboratory experiments in psychoacoustical and soundscape research indicate that participants perceive a reproduction sound level lowered by 8–10 dB as more plausible than the original level. This bias supposedly roots in an adaptation of perceptual loudness scaling to the laboratory environment, that is overall quieter than urban outdoor soundscapes. To gain further insights into the nature of such loudness bias, we conducted a listening experiment in both field and laboratory using a within-subjects design. Thirty-one participants visited a street and listened to the environmental sounds for one minute, while these sounds were also recorded using a dummy head. Thereafter, they listened to the recording in a quiet laboratory nearby and adjusted its level as they remembered it. About half of the sample did this immediately, the other half about 20 min after the recording. Results confirm a bias towards lower levels with a mean of about 8.9 dB, regardless of the time between the recording and the reproduction in the laboratory. Also, participants with higher musical abilities tended to select higher, more accurate levels, whereas noise-sensitive participants deemed lower levels appropriate. Results suggest that the hypothesized adaptation of perceptual scaling to the laboratory happens immediately and is affected by individual factors.