The physical positioning of speakers is key to creating mixes that translate well to other surround playback systems. Because the 5.1 format is the most widely used, this section covers 5.1 speaker placement. Much of this information can be applied to the other formats.
The International Telecommunications Union (ITU) 5.1 surround definition states that front speakers should be arranged left, center, and right, with the angle between the left or right and center speakers being 30 degrees. A narrower angle of 22.5 degrees is suggested for use in cinematic systems where the left and right speakers should be within four degrees of the edge of the screen.
In the studio, you should use the wider 30-degree angle, even if scoring for film. Use of this angle allows stereo signals to be auditioned correctly using the left and right speakers, without moving them each time you switch between stereo and surround mixes.
The three front speakers—left, center, and right—should be placed in an arc (not a straight line) at an equal distance from your listening position. The center speaker should be set back slightly from an imaginary line drawn between the left and right speakers. If this isn’t practical, don’t place the center speaker closer to the listening position than the left and right speakers. All three speakers should be at the same height—at ear level.
If possible, your listening environment should also include a position where the left and right speakers are at an angle of 45 to 60 degrees from the ideal central “viewing” position. An angle close to 45 degrees is preferred if watching movies, as it approximates the way film soundtracks are mixed and monitored. A wider angle, with the left and right speakers farther apart, is recommended if your system is principally used for listening to music, rather than watching movies.
It’s not essential to have a full surround setup in the studio. If you have a home theater system, make your surround mix in the studio, then listen to or watch it in your theater room.
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 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 directly 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, 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.
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.