Current convention dictates that sound levels are assessed and reported using the unit ‘decibel’. It can be reported in a number of different ways – sound pressure, sound power, sound intensity, A/B/C weighting filters etc. The decibel is also mathematically complex, as it represents a ratio to a reference pressure and is based on a logarithmic scale.
Decibels are very much an accurate indicator of how ‘noisy’ a product is, and form the basis of the current Quiet Mark award scheme. As the science of acoustics evolves though, finding new ways to measure and assess sounds, our assessment methods will follow.
Sound Quality is the cutting-edge of acoustics right now. It looks at all of the different elements of a sound – loudness, sharpness, roughness, tonality – and how these are perceived by the human hearing system. By using panels of people, listening to and grading different sounds, you get a whole new level of insight on the types of sounds that humans prefer. For example, a mosquito’s wings make a very quiet sound, however for most it is a very unpleasant sound to listen to due to the frequency.
Quiet Mark is working with HEAD acoustics, who are at the forefront of measuring and assessing sound quality, with a view to launching an enhanced Quiet Mark award in 2017 for sound quality. This will recognise products that are not only less noisy, but create more pleasant sounds for the human ear.