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Monday, 3 June 2013
How to set up a Home Theatre: Speaker placement
SETTING up a home theatre involves careful consideration and knowledge. This guide tells how to set up five speakers, one subwoofer, in a room.
Most set-up guides show an idyllic viewing room with a perfect rectangular shape, no door, and a single chair in the middle with speakers placed neatly around it. In the real world, most people will have to make the best of what they have.
Front and Centre The front speakers should go to the left and right of the television screen and there should be at least a few feet between the speaker and the TV. Try to avoid putting the speakers right up against the TV; separating the front speakers with some space gives the sound a larger feel.
For floor standing speakers, this can be difficult, since it is easier to accomplish this placement with wall mountable speakers. However, avoid spreading the speakers out so much that they are in the front corners of the room; this can create some weird soundwave after-effects.
The best location for the side speakers is in the middle of the space between the side wall and the screen. If there is only one side wall to deal with, place the opposite speaker the same distance from the screen. Speaker height should put the tweeters at the same height as the listeners’ ears when seated. For higher mounts, angle the speakers so that they are pointed down and slightly in. Angling in of the speakers to a small degree is okay, but do not angle them so far in that they are pointed at the listener.
The centre speaker should be placed directly below or above the middle of the screen. Unlike the sides, this speaker should be as close as possible to the screen and should be angled up or down directly at the listener.
Rear speakers If speakers were kids, the rears are twin problem children. Except for those few who remodel a space specifically for home theatre, optimal placement of the rear speakers is an exercise in compromise. Enemy number one is room size. Lots of people have their couches flat up against the back wall, leaving little room for speakers behind them. Or, on the flip side, homes will feature a wide open living space with miles between the listening area and the nearest back wall, which does not bode well for speakers on stands sitting in the middle of the open floor plan.
The best solution in both situations is to go up. Mount the speakers up near the ceiling and angle them straight down or towards the listening area. If mounting is not possible, it is acceptable to move the couch out a few inches and place them on the floor pointing straight up. The rear speaker volume levels will most likely have to be maxed out in this scenario.
While it is tempting to put the rear speakers on each side of the listening area pointing directly towards each other headphone style, it is not recommended since it can create some odd signal amplifications and cancellations in the listening area.
The subwoofer A quick lesson in reflective sound: The sound level of a subwoofer is multiplied by the number of solid flat surface surrounding its location. A subwoofer in the middle of the floor is increased by a factor of one. Placed against a wall, its sound is increased by a factor of two, and a subwoofer placed in a corner will have its sound level increased by a factor of three.
From a pure sound level perspective; corner placement is ideal. However, the low frequency sound waves produced by subwoofers are very large (a 100 Hz sound wave is about 11 feet long) and will resonate around the room. This can create hot spots where the sound is greater and dead zones where the sound is lower.
The common advice is to move the subwoofer around the room and then test it to make sure there are no dead zones or hot spots in the listening area. A better advice is to realise that there is an inverse relationship between the sub and the listening position. Simply put, you just place the subwoofer in the prime listening area and then slowly walk around the edge of the room. Once a good spot is found with an even volume level that is not already occupied by other furniture, the subwoofer can be placed there.