Apple Final Cut Pro 7 - Manual (Page 963)

Note: Different devices define these ranges differently; the following ranges are
approximate.
Low Frequencies
Low frequencies range from approximately 20 Hz to 250 Hz. Audible bass frequencies
start around 20 Hz, though many speakers cannot reproduce frequencies this low. This
is an example of how audio meters can be deceiving, because the meters may show very
high signals but the speakers are not capable of making sounds that low. The lowest
frequencies are felt as well as heard and require the most power to amplify. Often,
subwoofer speakers are used just to handle the low frequencies in the mix (the 0.1 channel
in a 5.1-channel surround sound mix is a dedicated low-frequency effects channel).
If you are trying to increase the impact of sounds like kick drums or explosions, add gain
around 30 Hz or so. Filtering out 60-80 Hz removes a lot of low-end noise and rumble
from wind or microphone handling. Between 150 and 250 Hz, you can add “warmth” to
the audio signal (or subtract it).
Midrange Frequencies
Midrange frequencies range from approximately 250 Hz to 4000 Hz. Humans are most
sensitive to this part of the audio spectrum. Most of the frequencies that make speech
intelligible are in this range. You can make audio tracks stand out more in the mix by
subtly increasing the frequencies in this range. At the top of this range, around 4 kHz, is
where vocal sibilance occurs. Too much sibilance can be grating, but a little bit can make
the voice sound crisp and detailed. If your track has too much sibilance, try reducing the
4 kHz range.
High Frequencies
High frequencies range from approximately 4000 Hz to 20,000 Hz. The high end of the
frequency spectrum adds “brightness” or “brilliance” to a mix but does not affect factors
such as impact (bass) or speech intelligibility. High-end frequencies can be grating, so
don’t boost these frequencies too much.
Using Equalization Filters in Final Cut Pro
The following equalization filters are included with Final Cut Pro:
• 3 Band Equalizer
• Band Pass Filter
• DC Notch
• High Pass Filter
• High Shelf Filter
• Low Pass Filter
• Low Shelf Filter
• Notch Filter
963 Chapter 59 Using Audio Filters