About Audio Meters

Audio meters display the level of your audio signal in an objective way, helping you to set consistent levels throughout your program and ensuring that you have sufficient headroom and dynamic range.

Average and Peak Audio Levels

Before you begin to adjust audio levels, take a closer look at an audio waveform to better understand how it corresponds to what you hear during playback.

Figure. Diagram showing the peaks and average loudness of an audio waveform.

The most important distinction is the difference between an audio clip’s peaks and its average loudness:

  • Peaks: These are short, loud bursts of sound. In spoken dialogue, letters like P,T, and K at the beginning of words can result in peaks if the person speaking is close to the microphone. In music, peaks occur at the very beginning of sounds from percussive instruments such as drums.
  • Average loudness: The average loudness of a clip generally determines its overall perceived volume, and this is probably somewhat lower than the level of the peaks. In the sample waveform, the level of average loudness appears as the densest, darkest part around the middle. Average loudness, rather than the brief peaks, tends to influence your decision about mixing a sound higher or lower.

Analog Versus Digital Meters

The way you set your levels with a digital meter is different from the way you set levels on an analog meter. Compare a traditional analog audio meter with a digital audio meter:

Figure. Diagram showing a generic VU meter and a digital audio meter.

A digital meter displays the sample values of a digital audio signal. The scale on the meter is known as digital full scale, and the signal is measured in dBFS. On this scale, 0 dBFS represents the highest possible sample value. Any samples above 0 dBFS are clipped, distorting the original shape of the audio waveform. Once a signal is clipped, the original shape of the waveform cannot be recovered.

Figure. Diagrams showing a waveform, the waveform displaying clipping caused by too much gain, and the waveform displaying clipping after the gain is reduced.

Important: Final Cut Pro can handle digital audio levels above 0 dBFS by internally using 32-bit floating-point resolution for all audio processing. However, when you export or output to tape, the bit depth of your audio is usually reduced to 16 or 24 bits, so you still need to be aware of the 0 dBFS limit.

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, the signal may distort. If the voltage is much lower, the signal 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.

About Audio Meters in Final Cut Pro

Final Cut Pro uses peak audio meters, which respond very quickly to the audio signal, alerting you to potential peaks over 0 dBFS. The meters in Final Cut Pro display a peak level indicator, which is a yellow line that shows recent peak levels for up to 3 seconds (assuming a higher peak hasn’t been reached).

Figure. Final Cut Pro audio meters showing a yellow peak level indicator.

The peak level indicator can help you get a sense of the dynamic range of your mix because you can compare the current levels to recent peaks. For more information about peak meters, see Average and Peak Audio Levels.

There are several audio meters in Final Cut Pro:

Clipping Indicators

The Master audio meters and the floating audio meters have a clipping indicator that lights up when the output signal reaches 0 dBFS. Once the clipping indicator is lit, it stays on during playback to let you know that part of your signal clipped. The clipping indicator also stays on after you stop playback, but it is turned off each time you start playback.

To turn off clipping indicators during playback
  • Click the clipping indicators in the Master audio meters or floating audio meters.

Figure. Audio meters showing the red clipping indicator.

Floating Audio Meters

The floating audio meters display the output levels of the Viewer or Timeline with a simplified stereo display. If you’ve set up more than two audio outputs in the Audio Outputs tab of the Sequence Settings window, the floating audio meters display the highest levels of any audio outputs in either the right or left channel. The highest level of any odd-numbered audio channel is displayed in the left meter, and the highest level of any even-numbered audio channel is displayed in the right meter.

Unlike the track and Master audio meters, the floating audio meters do not show levels above 0 dBFS.

Figure. Comparison of the floating audio meters and the Master audio meters.