One of the main reasons why some sounds are loud and others quiet is the effect of a temperature gradient. This temperature gradient makes the air near the ground have a lower index of refraction than air above it. This temperature difference bends sound waves towards the earth. This is a well-known phenomenon in optics.
Acoustic energy
The acoustic energy that causes some sounds to be loud and others to be quiet is produced when an object vibrates. The sound waves then travel through the medium, carrying kinetic energy with them. Loud sounds are produced by waves that have a higher amplitude than the surrounding medium. For example, if you listen to very loud amplified rock music, you may be hurting your ears. These sound waves can be as loud as 120 to 140 decibels (dB) and may cause temporary or permanent damage to your hearing.
As a sound travels away from its source, it spreads out the energy in it, resulting in a spherical shockwave. As the shockwave travels further, it spreads out the energy more evenly and less intensely. The same amount of energy is spread over a larger area.
Frequency
We hear sounds in a variety of frequencies, and the frequency of a loud sound is much different from the frequency of a quiet one. The frequency of loud sounds, or pitch, is measured in hertz (Hz). It refers to the number of oscillations in a sound wave per second.
Generally speaking, loud sounds produce high pitches, whereas low pitches produce low pitches. In general, human ears can detect sound frequencies ranging from 20 Hz to 20,000 Hz. However, people with hearing loss have trouble recognizing higher frequencies. Moreover, speech is typically found in the range of 100 to 8000 Hz, and can sometimes be difficult to understand when the frequency is higher than this.
Interestingly, louder sounds can also be found on other planets. For example, gas giants in our Solar System have denser atmospheres than Earth, which makes it possible for them to create louder sounds. These planets are also known to have powerful storms.
Amplitude
Amplitude is the change in pressure caused by a sound. It can be expressed as peak to peak pressure or the root-mean-square (RMS) pressure. The RMS value is obtained by squaring the amplitude values and converting them back to amplitudes. Amplitudes are proportional to the flow of sound energy.
Amplitude measures are often used in biological acoustics. An oscilloscope measures successive cycles, while a sound level meter records average amplitude over a longer period of time. Both types of amplitude are useful for analyzing sound, though they have their own specific applications.
The amplitude of sounds is directly related to their loudness, and the higher the amplitude, the louder the sound. Sound intensity is measured in decibels (dB), a scale that is a logarithmic scale, which means that each 10 dB difference represents an increase in sound intensity of ten times.
Motion after effect
You may have noticed that some sounds are loud while others are quiet. This phenomenon is called the motion after effect. This effect can affect lightness-darkness perception, colour perception, and hearing. After the brain has adapted to a high baseline level of noise, the absence of sound is perceived as quieter than other quiet sounds.
Researchers have studied the motion after effect of sound by presenting arbitrary sounds accompanied by motion information. They found that the auditory-induced effect of sound was persistent for at least 2 days. This finding suggests that the perceptual system can rapidly establish new neural representations based on the sound-motion pairings.
Intensity
Sound intensity, also known as acoustic intensity, is the power carried per unit area by sound waves. It is measured in SI units, such as watts per square meter. Sound intensity is important because it can affect the way we perceive sounds. The intensity of sounds depends on many factors, including the volume and frequency.
Sound intensity models predict the intensity of sounds based on their frequency. These models assume that short tones are louder than long tones. This is because the intensity of sounds is the amount of energy that is transferred over a short period of time.
