tags: mus-407 sound sound-properties amplitude decibel

Decibel Scales

There are two distinct cases of the [decibel] scale for use of measurement:

Sound pressure level

• dB SPL (decibel sound pressure level)
• used for measuring sound level of an acoustic environment
• 0 dB = threshold of hearing
  • below 0 dB, you cannot hear it
• 120-130 dB = threshold of pain
  • when representing [dynamic range] through [bit depth] in a digital system, we don't need to exceed a bit depth that allows for more than the pain threshold

Electrical signal level

Decibels are often used to describe [audio signal] levels.

• analog: dBV (voltage) , dBu (unloaded)
• digital: dBFS (relative to full scale)
• What does 0 dB mean?
  • analog: nominal operating level, optimal I/O linearity
  • digital: highest representable level without introducing clipping/distortion
    • positive digital dBFS values are bad: clipping, nasty distortion
• signal levels below 0 dB have negative values