Apple Final Cut Pro 5 - Manual (Page 943)

156 Part I Media and Project Management
Unlike a compressor, which affects the loud parts of a signal, expansion affects the
quiet parts of the signal:
 Threshold: This slider defines how low the lowest portion of the clip can be before
expansion is applied. This is the first setting you’ll adjust.
 Ratio: This affects how much expansion is applied to boost the signal.
 Attack Time: This defines how quickly the filter reacts to changes in volume (the
default is usually fine, but you may want to experiment).
 Release Time: This defines how slowly the filter lets go of the change in volume it
made (the default is usually fine, but you may want to experiment).
Noise Reduction Filters
Final Cut Pro has three noise reduction filters for use in specific situations:
 Hum Remover
 Vocal DeEsser
 Vocal DePopper
Hum Remover
The Hum Remover lets you get rid of “cycle hum” that may have been introduced into
your audio recording by power lines crossing your cables, or by a shorted ground wire
in your setup. Hum from power sources generally sounds like a low buzzing and has a
frequency that corresponds to the electrical power in your country (for example,
countries in North America use 60 Hz AC power, while most countries in Europe use
50 Hz power).
 Frequency: This slider lets you select the frequency of hum that this filter will attempt
to remove. Different countries use different power frequencies, so you need to
specify exactly what frequency to tune out. In general, most AC (alternating current)
operates at either 50 or 60 Hz.
 Q: This slider allows you to select a range of frequencies to filter. If the important
elements of your recording overlap into the frequencies that are being filtered out,
you might want to narrow this value somewhat.