Wel een ander doel ja. Maar het effect kan dus hetzelfde zijn.
Ik kreeg ongevraagd een berichtje over een onderzoek. Ik weet niet wat ik er mee moet maar plaats het maar hier:
http://www.icben.org/2014/papers/Team4/ ... Ueda_1.pdf
Thirty-one subjects (89%) answered that the sound could be heard clearly, and four
(11%) answered that the sound can be heard. Figure 5 shows the evaluation results
of the impression of the sound generated (the scores were averaged among 35
responders for each adjective). The discomfort score was 4.0, indicating that many
responders felt the sound generated was uncomfortable. The score of “noisy” was
also high. For physiological influences, the scores of “pain in the ear” and
“restlessness” were high, while the scores of “nausea and dizziness” were relatively
low.
For the degree of the sound source awareness, 43% of the subjects answered that
they “know (the device).” However, when asked about the kind of sound, many of
them mistook it for a “mosquito sound.” In addition, some responded that “my head
may split” and “I will never come here again because of the pain in the ear.”