Page 14 - INCOLA EXCLUSIVE DATA CATALOGUE

Sound Insulation

2.1 Characteristics of Sound

Objects, usually being elastic in nature, produces and transmits sound
waves. Sound waves carry the energy from the source of vibration. This
energy is transmitted through various media. In order for a sound caused
by a vibration to reach our ears, there needs to be a versatile
environment between the source of the sound and our ears – in solid,
liquid and/or gaseous forms.

2.2 Denitions of Sound

• Tone: An audible hum possessing the same level of vibration in a single frequency.
• Harmony: Several tones that wave together harmonically.
• Sound: Several partial tones that are not harmonic.
• Noise: A mixture of disturbing tones and harmonic sounds.

Harmony Sound Noise

Figure 4. Characteristics of Sound: Harmony, Sound and Noise

2.3 Loudness of Sound (Volume)

The loudness of sound is defined as an atmospheric pressure of a
vibration. Loudness is measured in decibels (dB). The human ear can
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distinguish a 1000-Hertz sound once it has reached or exceeded
0.00002 N/cm2 (0 dB) of pressure. The human ear has a hearing range
of 30 dB(A) to 130 dB(A).

Typical Sound Typical Loudness (dB(A))
Whisper 30
Talk 40-60
Yell 80-90

Plane take-off 120-140
Gunshot (short distance) 130

Table 4. Typical Sounds and Loudness

Derived unit of frequency defined as cycles per one second.
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