Transcript EFC Media Center Training

EFC Media Center Training
Introduction
• What is Sound ?
• Properties of Sound
– Speed 340m/s
– Frequency / Pitch
– Loudness / SPL
Introduction
Range (dB Sound Pressure Level)
0 - 30 Very Quiet
This is the threshold of human hearing, up to
the sound of a quiet whisper.
31 - 50 Quiet
This is an average quiet house, with maybe the
sound of a fridge running or someone
moving around.
51 - 70 Normal
Regular daily sounds like people talking.
Introduction
71 - 90 Loud
This is the point where a sound becomes annoying or
distracting. Vacuums or a noisy car on a busy street
are at these levels.
91 - 110 Very Loud
Most people will try to avoid being in areas this loud.
Prolonged exposure can cause permanent ear
damage. Temporary effects, like "stereo hiss", may
happen.
111 + Painful!!!
Even limited exposure to levels this high will cause
permanent hearing loss.
Introduction
• How do we perceive sound
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–
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20 ~ 20KHz range
Perceived loudness at different frequency
Perceived spectral response at different
average loudness level
Introduction
• Purpose of Audio System in Church
– Amplify voices so that it will be noise free,
intelligent, with sufficient volume even for our
elderly.
• Purpose of Sound Engineer
– To operate and maintain audio equipments so
that our congregation is free to worship
without distractions.