Realistic noise reduction measures require soundscape recordings rather than pink noise.

Evidence

Adaptive ANC measurements require a more ecologically valid test signal than uncorrelated pink noise, so engineers have created methods to record and reproduce different environmental soundscapes or noisescapes through an array of loudspeakers and measure how effective the headphone reduces the noise. A solution from Head Acoustics (Schäfer et al., 2019) uses an eight-microphone array to capture different noisescapes and reproduces the recordings through an 8-channel loudspeaker system. Butterworth (2024) visited Head Acoustics lab and describes the recordings ranging in level from 82 to 96 dBA. They include leaf blowers, lawnmowers, woodshop with power tools, airplane cabins and music venues. He provides a description of the measurements and some test results for two popular ANC headphones compared to two relatively inexpensive passive ear plugs (see Butterworth, 2024, figure 1). The entire process from measurement to processing results can take up to 3 hours but yields several psychoacoustic metrics that capture how effective the ANC reduces noise in phons and improves the speech intelligibility. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1757

Categorization

• XREF: Connects to the reader’s broader interest in ecologically valid stimuli vs. laboratory artifacts, similar to issues in architectural acoustics. — connects to: Noise-level reduction alone often fails to improve sonic environments perceived as unpleasant. — Almo Farina, Soundscape Ecology: Principles,…, 71