Inventor of decibel scale
Thus we have seen how overall gain can be calculated by adding individual gain instead of multiplying them.
In decibel scale this overall gain is 10 log15 11.76 dB which is nothing but 4.77 + 6.99. Logarithms (or logs for short) are simply a way of describing numbers which vary by very large amounts in a much smaller range. Now in logarithmic or dB scale these gain are 10 log3 4.77 dB and 10 log 5 6.99 dB respectively. By definition, a decibelabbreviated dBis a unit to measure the ratio of two power levels. For example, the 5 of the bottom scale corresponds to the 15 of the top scale, meaning that 3×515. Just about every piece of audio equipment (microphones, loudspeakers, sound cards, amplifiers, mixers, etc) will have specifications expressed as logarithms (i.e. In this illustration, two log scales are aligned to multiply by 3. 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. A decibel is a logarithmic value to the base 10. It is normally measured using the A scale, which approximates the human ear’s response to a wide range of frequencies. To make a sound twice as loud, you need to multiply its intensity by about 10. Decibel: Named after the inventor Alexander Graham Bell, a decibel (dBA) is the unit used to express the intensity of sound. 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.