Apple Soundtrack Pro 3 - Manual (Page 339)

To connect physical outputs for monitoring surround sound
1 Connect the audio interface to your computer.
For detailed information on connecting your audio interface to your computer, see the
documentation that came with the audio interface.
2 Double-click Audio MIDI Setup in the Utilities folder, then choose the audio interface from
the Default Output pop-up menu.
For more information, see Setting the Audio Input and Output .
3 Connect your 5.1-channel surround sound speakers to the appropriate outputs of your
audio interface.
Soundtrack Pro uses the SMPTE/ITU standard for routing output channels.
Speaker Audio interface output
Left 1
Right 2
Center 3
LFE 4
Left Surround (Ls) 5
Right Surround (Rs) 6
For detailed information on connecting external speakers to your audio interface, see the
documentation that came with the speakers.
Stereo Mixdown
If you have set up a project for surround mixing, including surround panners and surround
channel assignments, but you do not have sufficient output jacks for surround playback,
Soundtrack Pro automatically provides a surround-to-stereo mixdown of what would
otherwise be sent to jacks 1-6. This stereo mixdown follows the Dolby guidelines: the Ls
and Rs channels are attenuated by 3 dB and mixed into the Left and Right channels. The
Center channel is also attenuated by 3 dB and mixed evenly into the Left and Right
channels. The LFE channel is discarded.
Surround Speaker Placement
There are several ways you can arrange 5.1 surround speakers for playback. You can follow
the International Telecommunications Union Operational Bulletin No. 775 or the “ITU
Standard” for 5.1 surround sound. Here are the basic points of this recommendation:
• Place all the speakers on the same plane. In other words, if you place some speakers
on the floor and mount some on the ceiling, you will defeat the psychoacoustical
benefit of having surround speakers in the first place.
339 Chapter 13 Mixing Surround Sound