Adobe AUDITION 1.5 - Manual (Page 280)

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Digital Audio Primer
Amplitude resolution is just as important as frequency resolution. Higher bit depth means
greater dynamic range, a lower noise floor, and higher fidelity. When a waveform is sampled,
each sample is assigned the amplitude value closest to the original analog wave. With a
resolution of two bits, each sample can have one of only four possible amplitude positions.
With three-bit resolution, each sample has eight possible amplitude values. CD-quality
sound is 16-bit, which means that each sample has 65,536 possible amplitude values.
DVD-quality sound is 24-bit, which means that each sample has 16,777,216 possible
amplitude values.
Higher bit depths provide greater dynamic range.
Where Adobe Audition fits into the process
When you record audio on your computer, Adobe Audition tells the sound card to start
the recording process and specifies what sampling rate and bit depth to use. The sound
card determines the supported sample rates and bit depths. Most cards can record and
play at CD-quality settings, but many also support other settings (for example, a 48 kHz
sample rate, which is common in film and video post-production). Your sound card
probably has both Line In and Microphone In ports through which it can accept analog
signals. The sound card samples the audio at the specified sample rate and assigns each
sample an amplitude value. Adobe Audition stores each sample in sequence until you stop
recording. Once you've recorded the audio, you can use Adobe Audition to edit the audio
or save it to disk as a file.
When you play a file in Adobe Audition, the process happens in reverse. Adobe Audition
tells the sound card that it will play a file and sends a series of digital samples to the card.
The sound card reconstructs the original waveform and sends it as an analog signal
through the Line Out port to your speakers.
192 dB
48 dB
0 dB
96 dB
8-bit 16-bit 32-bit
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