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Loudness of Sound

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Last updated date: 28th Mar 2024
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Introduction Loudness of Sound

The sounds we encounter in our daily lives vary, and we are equipped with mechanisms to analyze and comprehend these variations. Mothers have a different voice from those of the children they speak to. Have you ever thought about why everyone has a different voice? We need to understand the loudness of sound, its pitch, and the difference between them.

What is the loudness of sound? Which factors determine it?

Answer:

There is a relationship between the loudness of a sound and its amplitude. In general, loudness refers to how large the amplitude of the sound wave is. The decibel (dB) scale for measuring loudness is directly proportional to the square of the amplitude of the vibration. Thus, noise is defined as sounds above 80 dB. 

Explanation:

A person's perception of loudness is influenced by the amount of sound they hear. A sound's volume is determined by its intensity, which is itself governed by its frequency. Sounds are measured by their intensity or the energy they hold. Intensity is measured in decibels (dB). In this way, the loudness of sounds is determined by its intensity. There are two factors that determine how intense a sound is: the size of the sound waves and the distance from their source.

  • Sound waves are measured according to their amplitude.

  • Wave amplitude is determined by the energy that caused them.

  • Waves with larger amplitudes have more energy and are more intense, so they are louder.

  • The following table gives us data about different sound sources.

Normal Breathing

10 dB

Soft Whisper (at 5 m)

30 dB

Normal Conversation

60 dB

Busy Traffic

70 dB

Average Factory

80 dB

 

In sound waves, the amplitude is directly associated with loudness, since all waves have the same amplitude. An ocean wave on a calm day may only be a foot high, whereas a surf wave can reach heights of 10 feet or more. As the amplitude increases during a storm, it may reach 40 to 50 feet.

Pitch of sound

  • Depending on how fast the waves vibrate, the effect is different.

  • Sound that has a high pitch and a high frequency is called shrill or shrill sound. A sound's pitch is expressed as its frequency of vibration if it has a lower pitch.

  • While birds produce high-pitched sounds, lions produce low-pitched sounds when roaring.

  • An average woman's voice has a higher pitch than an average man's.

Pitch vs Loudness

Although these two phenomena sometimes appear to be the same, they are not exactly the same. The key difference is the quality of the tone. Sound pitch is a response our ears have to a sound's frequency. In contrast, loudness is determined by the strength of the wave. Generally speaking, pitch accounts for the difference in voice quality between individuals.

 

The Pitch and loudness of sounds are determined by their frequency and amplitude, respectively. It is amazing that trained musicians have the ability to detect a difference in frequency between sounds that is as little as 2 Hz.

Loudness

Pitch

As a sound property, loudness can help distinguish between loud and faint sounds

Pitched sounds are distinguished from one another by their pitch characteristics.

The level of loudness is determined by the amount of energy received by the ear during a given period

An ear's pitch is determined independently by the amount of energy it receives at any given time

There is no relationship between loudness and frequency

The pitch changes as the frequency changes. A shrill sound becomes louder as the frequency rises.

 

The Loudness of Sound Formula

L = log (I)

 

Where I: Intensity of sound.

 

Difference of loudness, L2 - L1 = 10 log10 \[(\frac {I_1}{I_0})\]

The Intensity of the Sound

Accordingly, the intensity is defined as the ratio of energy per unit time per unit area, and since the ratio of energy to time is the same as the power per unit area, the intensity is simply the power per unit area.

 

Intensity = \[\frac{\text{Energy}}{\text{(Time * Area)}}\] or Intensity = \[\frac{\text{Power}}{\text{Area}}\]

 

The units used to express the intensity of a wave of sound are Watts per meter2.

FAQs on Loudness of Sound

1. What do You Mean by Loudness of Sound?

Loudness of Sound Definition: It refers to how loud or soft a sound seems to a distant listener. The loudness of sound is determined by the intensity or amount of energy present in sound waves and is expressed in decibels. As the level of decibel gets higher sound waves have greater intensity and sounds are louder.

2. What are the Characteristics of Sound?

Characteristics of sound are Pitch, Loudness, and Quality.


Pitch: It is based on the frequency of the sound wave. A note has a lower pitch when the frequency is low, and a note of a higher frequency has a high pitch. The word ‘pitch’ is frequently used in music. We can distinguish a female and male voice without seeing them.


Loudness: It is a feeling of how strong a sound wave is at any place. It is a relative term and has no dimension quantity. It is based on the amplitude of the vibration and will be louder when the amplitude is high.

The pitch of a sound is dependent on the frequency while the loudness of a sound depends on the amplitude of sound waves. These two phenomena are considered to be the same sometimes, but they are not the same. They both differ based on tone quality Whereas loudness is dependent on the energy of the wave.


Quality: The word Quality is also known as Timbre. As we know different sources produce a different variety of sounds, the timbre helps us to distinguish between them. A sound of good quality is good to listen to. The instruments having different shapes and sizes create different harmonics of loudness hence their sound can be distinguished easily.

3. Explain the Decibel Formula?

A decibel of 0.1 bel is said to be equal to 10 times the common logarithm of the power ratio. It is said to be expressed as a formula that is the intensity of a sound in decibels is 10 log10 denoted as S1/S2 where letter S1 and S2 are said to be the intensity of the two sounds.

4. How Would You Describe the Loudness of Sound?

The perceived loudness of a sound is based on its perceived intensity by a distant listener. The decibel level indicates the intensity of a sound depending on its energy level. The decibel level increases with the intensity of sound waves. This leads to louder sounds.

5. Can you explain the Decibel Formula?

According to this formula, decibels of 0.1 bel are equal to 10 times the common logarithm of the power ratio. It is stated that a sound's intensity is expressed as 10 log10, which is written as S1/S2, where S1 and S2 represent the two intensities of the sound.

6. What are loudness and intensity?

In simple terms, loudness is a measure of how the ear responds to a sound. It is defined as a measure of how much power is transmitted per unit area. Decibels (db) measure loudness, while Watts per meter square (W/m*2) measure intensity.

7. What is the normal loudness range?

An average, healthy young person's hearing frequency range is about 20 to 20,000Hz. It is considered harmful to exceed 85dB in the loudness range, even though the standard range is 0 to 180dB. The upper frequencies of our ear lose their sharpness as we age.