In fact, “miles of standard cable”-MSC-was probably the first measurement, giving way to Bell Lab’s Transmission Unit-TU-in 1924.Ĭapitalism being capitalism, a number of measurements were put forth by competitive entities. They needed a measurement, one to define the amount of signal lost over, say, a mile of standard cable. To fix the situation, engineers needed a method of quantifying this loss in the first place.

Engineers immediately saw that early phone calls lost signal strength over distance: signals grew fainter the further they had to travel.

The decibel’s history is found in communications-particularly, the cables that carried phone calls. The Telegraph? Both the British Royal Navy and the Emperor of Russia were involved in the earliest, practicable designs. The radio? Same deal: it transmitted messages to soldiers without the need of telegraph lines. The compressor? Originally, it was used to ensure no radio orders to troops would be inaudible. Logarithms (or logs for short) are simply a way of describing numbers which vary by very large amounts in a much smaller range.Fun fact: you can generally assume that your favorite piece of audio technology was invented for the purposes of the military, communications, or communications for the military. Just about every piece of audio equipment (microphones, loudspeakers, sound cards, amplifiers, mixers, etc) will have specifications expressed as logarithms (i.e. We need to get familiar with the idea of a logarithm. The decibel is a better fit to how our brains perceive sound. The relationship between perceived loudness and the decibel is a straight line. On the next graph below, a logarithmic decibel scale is used and now the curve becomes a straight line. Our ’10x’ rule means that as the overall level increases, we need increasingly large changes in intensity to get a similar change in loudness. An intensity of 1,000 is also half as loud as an intensity of 10,000. So an intensity of 1,000 is twice as loud as an intensity of 100. To make a sound twice as loud, you need to multiply its intensity by about 10. In the graphs below, the x-axis represents the perceived loudness of a sound, and the y-axis represents the acoustic intensity needed to create that loudness. After analysis, I could offer various recommendations to rectify the issue − all distinctly individual from each other, as acoustics can be affected by nearly everything!” Rob Bungay, Acoustic Consultant, WSP What are decibels? To understand and try to reduce these causes of complaints, among other things I installed sound level meters throughout the room to record noise levels during the day and night, and used acoustic models of the space to assess changes within the room. “I recently worked on a multi-bed intensive care ward where patients and visitors were complaining about the intrusive noise made by the alarms from bedside monitors.

In acoustical and audio engineering, decibels are used everywhere because knowing how loud a sound is important whether you’re assessing whether the noise from a new road is going to be a problem or setting the loudness of music in an arena. Graphic: Nick Maroulis Where are decibels used? When a sound is perceived to double in loudness, this corresponds to roughly an increase in 10 dB. It makes things easier if a logarithmic scale is used this is what the decibel scale is. The ratio of intensities between silence and ‘ow that hurts my ears’ is about 1:100 million million. The human ear is capable of hearing very quiet (low intensity) sounds and extremely loud (high intensity) sounds.

Decibel scale decibel scale