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Working with audio

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Working with audio

  1. 1. Working with Audio Sound and Audio Engineering
  2. 2. Capturing Audio • Convert changes in air pressure into electrical voltages • A microphone is a transducer (converts form of energy). • Electrical voltages are “analog.”
  3. 3. States of Sound • Acoustic (Sound Waves) • Analog (Electrical Voltages) • Digital (Numerical Values) • Acoustic  Analog  Digital (and back again) – Analog to Digital Converters – Work with audio in a non-linear way on computer, etc. – Send it back out through cables to speakers into sound waves into air and into ears, etc.
  4. 4. Sample Rate • Number of samples per second (also expressed in Hz) – 8,000 Hz – Telephone, Walkie-Talkies – 44,100 Hz – Audio CD – 48,000 Hz – DVD – 96,000 Hz – HD, Blue Ray Discs – 192,000 Hz – Highest currently available
  5. 5. Higher sample rates = greater accuracy
  6. 6. • Dynamic Range: available range of volume between the loudest and the softest audible sounds. • Signal to Noise Ratio: the difference in volume between what you want to hear (signal) and what you don’t want to hear (noise).
  7. 7. Bit-Depth • Dictates the number of discrete volume levels that create the dynamic range available in digital audio.
  8. 8. Sample Rate and Bit-Depth • Camera Analogy: Sample rate is how many pictures you take in a second, bit-depth is the number of colors your camera can discern. • Higher of each gives you better quality but also gives you larger file sizes.
  9. 9. Waveform • Visual representation of digital audio file.
  10. 10. Digitized audio files in Pro Tools (editing software)
  11. 11. Audio File Formats • Uncompressed – WAV – AIFF – SD2 • Compressed – MP3 – AAC – WMA

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