10.6

909Logic Pro User Guide
This positioning creates a broad surround sound field throughout the listening area,
approximating cinema speaker systems. If the speakers are placed too far forward,
the rearward effect will be insufficient. If the speakers are too far back, the surround
information won’t be integrated with the overall sound field. Experiment with placement
and angles until the surround sound field seems to encompass you, rather than come from
behind you.
If your studio doesn’t have walls in the perfect place to mount surround speakers, try
placing them on stands above ear level. If you need to wall-mount the speakers, place them
well above ear level, and try aiming them at each other, toward the front, or to reflect off
the side walls.
LFE speaker
The LFE is a discrete effect channel for low frequencies (explosions, avalanches) in film
and TV soundtracks. In surround music mixes, LFE is used as a low frequency channel for
certain instruments (bass drum or electric basses placed on the center with a frequency
divider that sends lower frequencies to the LFE speaker.
Bass frequencies travel much slower than higher frequencies, and are less directional.
Ideally, you should place the LFE speaker (often, a subwoofer) in a central position in front
of the listening position.
Set surround speaker timing and levels in Logic Pro
Most people with undamaged hearing can identify where a sound is coming from:to the
left, right, in front, or behind them. Certain sounds, however, are very difficult to “position”
in relation to the listening position. For example:
• A gunshot or car backfiringis hard to place because the sound is both loud and
quick. You may initially be able to tell that it came from your left or right but not
where, specifically, to the left or right it came from. This is because early reflections
(reverberations) rapidly build up and diffuse, making them hard to discern, directionally,
from the initial sound peak.
• Aircraft jet engines are a low rumble that is hard to place until the plane flies directly
overhead. When it does, the volume of the sound, and the higher frequencies of the jet
engines, enable you to hear it moving from left to right or front to back.
Some sounds are easier to place:
• Trucks, cars, and motorbikes generate a constant combination of low- and high-
frequency sound, allowing you to track their movement.
• Individual human voices are sounds that people are most familiar with, and contain a lot
of high-frequency content.
In a surround playback system, you need to set different levels and different delay times
for each speaker. This allows you to compensate for latency perceived at the listening
position, which affects your ability to correctly “place” where sounds are coming from.
Level—in particular—can alter your perception of how close a sound is, so you should
ideally set the same level for the front left and right speakers. These speakers are usually
used for incidental music/effects tracks and the main score of a film, and also often carry
an amount of the dialogue track.