Digital Sound & Music: Concepts, Applications, & Science, Chapter 5, last updated 6/25/2013
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The difference between potential dynamic range and actual dynamic range is illustrated in detail
in the interactive Max demo associated with this section. This demo shows that, in addition to
choosing a bit depth appropriately to provide sufficient dynamic range for a sound recording, it’s
important that you use the available dynamic range optimally. This entails setting microphone
input voltage levels so that the loudest sound produced is as close as possible to the maximum
recordable level. These practical considerations are discussed further in Section 5.2.2.
Figure 5.15 Potential SQNR compared to actual SQNR
We have one more related usage of decibels to define in this section. In the interface of
many software digital audio recording environments, you’ll find that decibels-full-scale (dBFS)
is used. (In fact, it is used in the Signal and Noise Level meters in Figure 5.15.) As you can see
in Figure 5.16, which shows amplitude in dBFS, the maximum amplitude is 0 dBFS, at
equidistant positions above and below the horizontal axis. As you move toward the horizontal
axis (from either above or below) through decreasing amplitudes, the dBFS values become
increasingly negative.
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