Apple Logic Pro 9 - Manual (Page 1183)

Positioning the Surround Speakers
The rear speakers (surround channels) should ideally be placed at the same distance from
your listening position as the front speakers, at an angle of around 110 degrees from the
front center speaker. This angle is a compromise between producing an all-encompassing
sound stage (at 90 degrees) and the best rear-quadrant imaging (at 135 degrees).
The surround speakers should be placed alongside and slightly to the rear of (but not
behind) the listening position, well above ear level, to help minimize localization effects.
They should be aimed across the listening area, not directly at the listening position.
This positioning creates a broad surround sound field throughout the listening area,
which approximates cinema speaker systems. If the speakers are placed too far forward,
you won’t get sufficient rearward effect, and if the speakers are too far back, the surround
information will not be integrated with the overall sound field.
Your studio may not have walls in the perfect place to mount surround speakers. If this
is your situation, try these options:
If you’re in a rented space, place the surround speakers on stands above ear level.
Generally, placing surround speakers on the wall directly behind the listening position is
not ideal. If you have no other choices, mount them well above ear level, and try aiming
them at each other, toward the front, or to reflect off the side walls.
You can also try placing them to the sides or rear aimed upward, either on the floor, or
a couple of feet off the floor.
Experiment with placing and aiming the speakers until the surround sound field seems
to “wrap around” you, rather than seeming to come from behind you.
Positioning the LFE (Subwoofer) Speaker
If you mix “traditionally,” by sending the bandwidth-limited LFE signal (all frequencies
below 120 Hz from all channels) to a subwoofer in your surround speaker setup, you don’t
need to concern yourself too much with its placement.
Bass frequencies travel much slower than higher frequencies, and aren’t very “directional,”
so placing the subwoofer under the desk or to the left or right of the room (but in front
of the listening position) will be fine.
Speaker Timing and Levels
You may or may not have wondered why the front speakers are ideally arranged in an
arc, why the subwoofer positioning isn’t too important, and why specific angles are better
than others for surround speakers.
1183 Chapter 39 Working with Surround