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The advent of sound in film technology has revolutionized films beyond what we can fathom. Today we take video and television sound effects such as surround sound, Dolby Digital sound, etc. for granted. We cannot imagine video/television without sound. But let us try watching our favorite soap or for that matter our favorite music video without sound. Even the best visuals will fall flat.
Amateurs often tend to take utmost care of the shots at the expense of sound in their productions. The inclusion of every bit of sound in video ambience sound, music, sound effects, even the spoken word is a conscious decision and has to partner well with the visuals. The manner in which every bit of sound is included or excluded, and enhanced or downplayed, affects the programme to a large extent.
Sound is created when an object vibrates. Pluck the strings of a guitar. They create a sound because they vibrate. If you pluck the strings hard, the sound gets louder. The sensation of loudness depends upon various factors (in the case of the guitar, the kind of string and the pressure applied on the string). The intensity of sound is measured in decibel units (dB) and is logarithmic in nature. Therefore, if 10 dB is 10 times 1 decibel, 20 dB is 100 times 1 dB (10X10=100) and 40 dB is 10, 000 times 1 dB (10X10X10X10=10, 000).
The ‘threshold of hearing’, that is, when sound is just about audible, is about 0 dB. The following table shows sound levels of different situations:
| 0dB
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Threshold of hearing
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20 dB
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A quite living room
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50 dB
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Office space
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| 70 dB
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Main road
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| 90 dB
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Factory
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| 115 dB
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Thunder
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| 125 dB
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Airport
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| 130 dB
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Threshold of pain
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When sound levels increase beyond 130 dB, we begin to experience pain in the ears. This level can be termed the ‘threshold of pain’. Constant exposure to sound levels above 130 dB is dangerous for our ears. In fact, we begin to feel uncomfortable right at 70-80 dB. Anything beyond this range can be painful
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