How is Sound Level Measured?
Sound level is measured using a device called a sound level meter. It measures sound pressure level (SPL) in units of decibels (dB).
Here's how it works:
1. Microphone: The sound level meter uses a microphone to capture sound waves.
2. Conversion: The microphone converts sound waves into electrical signals.
3. Amplification: The electrical signals are amplified to a measurable level.
4. Measurement: The amplified signals are then processed to determine the sound pressure level in dB.
Decibel scale: The decibel scale is logarithmic, meaning that a 10 dB increase represents a tenfold increase in sound intensity. For example, a 40 dB sound is ten times louder than a 30 dB sound.
When Does Sound Become Noise?
The line between sound and noise is subjective and depends on various factors, including:
* Context: A sound that is pleasant in one situation might be considered noise in another. For example, music is enjoyable at a concert but would be considered noise in a library.
* Intensity: The louder the sound, the more likely it is to be perceived as noise.
* Frequency: High-frequency sounds are generally perceived as more annoying than low-frequency sounds.
* Duration: Prolonged exposure to loud sounds is more likely to be perceived as noise.
* Personal sensitivity: Some individuals are more sensitive to noise than others.
Generally speaking, sounds above 85 dB are considered hazardous to human health, and prolonged exposure can lead to hearing damage.
Examples of Sound Levels:
* 0 dB: The threshold of human hearing
* 10 dB: A whisper
* 30 dB: A quiet library
* 60 dB: Normal conversation
* 85 dB: Traffic noise
* 100 dB: A motorcycle
* 120 dB: A rock concert
* 140 dB: A jet engine
It's important to note that sound levels can vary significantly depending on the distance from the source and the environment.