Apple MA261Z/A User Manual - Page 640

Overview of Audio Filters Filters in Final Cut Express HD are always nondestructive, meaning they are applied to clips but not to the media files themselves. You can disable or remove filters at any time, so you can experiment without worrying about altering your media. The most useful Final Cut Express HD audio filters can be separated into four broad categories:  Equalization (EQ)  Dynamics (compression and expansion)  Noise reduction  Echo and reverb Note: You can install additional third-party Audio Units plug-ins as needed. Filter parameters can be viewed and adjusted in the Filters tab in the Viewer. Apply an audio filter to an audio clip, then click the Filters tab. You can also double-click a filter in the Effects tab to view its parameters in the Viewer, but you won't be able to hear any changes you make since the filter is not applied to a clip. For more information about applying filters and adjusting parameters, see "Applying Filters to an Audio Clip" on page 648 and "Making Real-Time Audio Filter Adjustments" on page 651. Equalization (EQ) Filters An audio equalizer allows you to increase or decrease the strength of an audio signal within selected frequency ranges, or bands. For example, a three-band equalizer may have a gain control for the lows, midrange, and highs, so you can change the sonic "shape" of a sound by turning up some frequencies or reducing others. In general, it is much better to subtract frequencies than to amplify them, as this eliminates the possibility of distortion. If you find that a sound is lacking "brilliance," or high-end frequencies, try filtering out some of the bass or midrange frequencies. The overall effect is that the high-end frequencies are stronger than the lower-range frequencies. It's easy to go too far when amplifying some frequencies, so get in the habit of reducing frequencies first. Particular kinds of sound-men's voices, women's voices, tape hiss, and traffic noise-all appear at different frequencies of the audio spectrum. EQ filters can be used for many things, from minimizing background noise in a recording to accentuating a narrator's voice over background music. EQ filters can also create effects like making a voice sound like it is coming through a telephone or loudspeaker (this is because telephones and loudspeakers generally don't reproduce the high and low frequencies, only the midrange). 640 Part VIII Audio Mixing