Analog 0 dB Versus Digital 0 dBFS
Even though audio is exclusively digital in Final Cut Pro, it is likely that your audio will
exist in an analog context at some point. Most digital workflows begin with microphones
and end with speakers, which are both analog devices.
On an analog meter, 0 dB is the optimal recording or output level of a device. If the
voltage is much higher, it may distort. If it is much lower, it may be lost in the noise
inherent in the device. On a digital meter, 0 dBFS refers to the highest audio level
allowed before clipping.
When you look at the meters in Final Cut Pro, you need to consider how the signal
level will correspond to an analog meter. Specifically, you need to choose a point on
the digital meter that corresponds to 0 dB on an analog meter. This point is where
your average signal level should be, providing headroom for occasional peaks.
Headroom is particularly important in digital audio because any audio that goes
beyond 0 dBFS during export or output instantly clips and sounds distorted.
The level you choose for your average audio level affects the potential dynamic range
of your mix. The lower your average signal is allowed to be, the greater the difference
between the average and loudest sounds, providing a larger dynamic range.
However, you should also choose an average level that allows a significant difference
between your quietest sounds and the noise floor.
There are several common digital levels used to correspond to 0 dB on an analog meter:
 –12 dBFS: This level is often used for 16-bit audio such as DV audio, and for projects
with compressed dynamic ranges, such as those for television or radio.
 –18 or –20 dBFS: This level is more common on projects with higher dynamic range,
such as professional post-production workflows using 20- or 24-bit audio.
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Part I
Audio Mixing