SMOKE alarms would save more lives if the noise they made was a little less shrill.
So say Dorothy Bruck and her colleagues at Victoria University in St Albans, Australia. They played nine different alarm sounds to adults in the early part of their sleep. Most fire-related deaths at home, whether the houses have smoke alarms or not, happen in the first 3 hours of slumber, when people are sleeping most deeply.
The team found that people woke fastest when exposed to a square-wave signal with a fundamental frequency of 520 hertz plus some other low tones. Higher-pitched “pure” tones…
