Apple Soundtrack Pro 2 - Manual (Page 310)

310 Chapter 9 Mixing Surround Sound
Placing Stereo Music in a Surround Mix
The simplest option for stereo music in a surround project is to just leave it in stereo. If
you just use the stereo panner for a music track, the left and right signals remain in
their respective channels. However, some surround mixes include a hint of music in the
rear channels as well. With the Surround Panner HUD, you can place the right music
channel somewhere between the right front and right rear position, with more
emphasis on the front speaker. Do the same with the left side and listen to the mix.
Make adjustments as needed.
Using the Center Channel
In a multichannel system, there are three ways to achieve a centrally placed sound image:
 Create a “phantom center” (mix sound to the left and right equally, as with stereo). This is
a common strategy, but it assumes the listener is seated exactly between the
speakers. The timbre of sound is not the same as from a direct speaker because of
cross-cancelation effects.
 Use the center channel alone. This creates a stable center image for listeners in any
location. (To prevent the audio from sounding too focused or narrow, its reverb can
be spread to the left and right channels.)
 Use all three front channels equally or in various proportions. This method allows for
greater control of the range of spatial depth and width. The phantom center can be
reinforced by additional signals in the center channel, which can be enhanced by
signal spread into the left/right pair. The disadvantage is that sound from all three
speakers may not blend well or may not arrive at the listener at the same time,
causing side effects such as comb filtering, shifts in tone color, or smearing. To
counteract these side effects, you can first process the additional signals to change
their spatial character, timbre, or prominence relative to the main center signal.
Using Surround Channels
Subtle surround effects can greatly enhance the listener’s sense of depth compared to
conventional stereo. Popular music often benefits from creative use of surround. But
don’t overdo it. The film industry guideline for visual effects applies equally well to
surround effects—don’t let effects distract the listeners from the story.