Demystify the decibel
E2S Warning Signals, independent manufacturers of high-performance audible and visual signals, has published an educational guide that seeks to ‘de-mystify’ the dB (decibel), one of the most common units in engineering, yet also one of the most confusing.
The guide can be found at www.e2s.com/soundbasics.
The main difficulty in comprehending dB measurements is that it is a log-linear scale, which, while it is very useful in representing very large differences in a more user-friendly scale, also compresses the scale.
The guide sets sounder output levels in context with some everyday examples. It also discusses the effect of frequency on perceived loudness and includes some rules of thumb for system designers who are specifying the output and location of warning sounders to provide the desired sound levels as part of a warning system.
