![]() To make this adjustment without altering the unit increase in intensity level for each factor of 10 increase in intensity, we need only divide each number in the left column by a factor of 10 12, keeping the right column unchanged. Actually, the sound intensities we deal with typically range from 10 –12 Watts/m 2 (threshold of hearing) to 1 Watt/m 2 (threshold of pain), so we prefer that the zero of the intensity level scale correspond to 10 –12 Watts/m 2 rather than 10 0. We see that each number on the intensity scale is the power of 10 of the intensity. Table 1 shows that each time the intensity increased by a factor of 10, there is a unit increase in intensity level. Since it is easiest to deal with factors of 10, the simplest scale that might be tentatively proposed is: Intensity Intensity-Level Scale: Since each jnd in intensity corresponds to the same multiplicative factor of 1.25 (a 25% increase), an appropriate scale to describe intensity levels should increase by equal additive amounts each time the intensity increases by the same multiplicative factor. In this example, the percentage increase in the stimulus is 10%.įor hearing, a jnd occurs with approximately a 25% increase in sound intensity I ( I = energy per second per unit area). Weber's Law: The minimum perceptible increase in the intensity of a stimulus is proportional to the percentage increase in the stimulus.Įxample: If the addition of one candle to 10 candles produces a just noticeable difference (jnd) in brightness, then the addition of 10 candles to 100 candles, or 100 candles to 1,000 candles, etc. Over the years of teaching physics and physics of sound, I developed a system by which decibels can be understood and estimated without the use of logarithms. Understanding and Estimating Decibels Without a Calculator or Logarithms ![]() Understanding Decibels Without Logarithms
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |