Design Tips for Home Theater & Whole House Audio Systems
Home Theater Speaker Design Guide
Speaker PlacementCenter Channel Speaker
The center channel speaker should be the first speaker you place in your home theater room. Because the center channel speaker's job is to anchor dialogue and other on-screen sounds to the screen, its position depends upon where you put your TV.
Place your center channel directly above or below your TV — centered, if possible.
If it's atop your TV, make sure the speaker's front edge is precisely aligned with the front edge of your TV screen. This reduces distortion caused by sound reflecting and diffracting off the TV's cabinet.
If possible, the height of the center channel speaker's tweeter should be close to the height of your front speakers' tweeters — ideally, within about 24" or less.
Front Left & Right Speakers
Your front speakers pull double duty: along with handling movie soundtracks, they're responsible for reproducing all of the sound when you listen to stereo music. This makes their position relative to your listening position especially important.
Position your front left and right speakers in front, and at equidistant points to the left and right, of your primary listening spot.
For the best possible sound, the tweeters should be at ear level when you're seated. Most floor-standing speakers are designed with this in mind; smaller speakers can be positioned on stands or mounted on the wall to achieve the proper height.
Make sure there are no solid objects (like furniture) blocking the pathway of the sound traveling to your listening location.
Your home theater's surround speakers are there to envelop you in sound and special effects, so you feel like you're actually in the middle of the action. Here are some recommendations to help you achieve this effect, but it's important to note that surround speaker placement is one area where positioning may vary widely depending on the room and furniture layout.
Ideally, your primary pair of surround speakers should be placed to the left and right of your listening position — either in line with it, or just behind it.
For a 6.1-channel system, place the speakers behind your listening position, facing the front of the room. For 7.1-channel system, place two speakers to the side and two behind.
Surround speakers should be placed high enough so that the drivers do not fire directly at your ears when you're sitting down. If your surround speakers fire directly at your ears, they can overpower your front speakers.
If your surround speakers are mounted on the side walls on adjustable brackets, experiment with aiming them. You may get good results from pointing them at the ceiling or toward the rear corners of the room.
Avoid locating a surround speaker too close to secondary seating. It will become a distraction for the person seated there.
A subwoofer delivers crucial impact in a home theater system, but is one of the least demanding speakers to position.
Low bass frequencies are omnidirectional, so you can place your subwoofer just about anywhere in your home theater room, with good results. It is best to place it in the same end of the room as your TV and not to close to any one seat.
Placing your subwoofer near a wall will generally result in more bass, and placement near a corner — where three room boundaries come together — will get you even more. Keep in mind that even though the bass increases as you place the sub near a wall or corner, the quality of bass may be slightly "boomier" and less controlled. Aim for a spot where you get a compromise between quality and quantity of bass.
One way to test the placement of your subwoofer is to put your sub in your listening spot, play some music, move around the room, and listen. You'll probably notice that the bass sounds a little bit different as you move around from location to location within the room — the spot where it sounds the best may be where you want to put your subwoofer.
Whole-House Audio System Design Guide
Single Zone Multi-Room SystemsWhen designing your distributed home audio system, one of the first questions you need to ask is this: Do I want a single-zone system or a multi-zone system? In a single-zone system, the same source is played to all areas that have speakers. A multi-zone system allows different sources to play in different areas at the same time (see next topic). The single-zone system is the most common. The audio sources- radio, CD, ipod/mp3 player, computer- are connected to an amplifier that drives speakers throughout the home. Each pair of speakers can be controlled by a switch box, volume control box, or wall volume control. These controls offer impedance protection to maintain the proper load on the amplifier. A local source can be added to a room to override the "house" source. A manual or automatic A/B switch selects the local source over the house source.
Multi-Zone Multi-Room SystemsA multi-zone system allows different sources to play in different areas at the same time. A zone can be one room or a group of rooms, such as a Master Suite. There are several companies making multi-zone control preamplifiers and multi-channel amplifiers. Keypad or remote control select the source and control the source components in each zone.
Speaker Selection & PlacementVirtually any type of speaker will work with a distributed audio system, so it is important to select speakers for each area that provide the sound quality you want and are aesthetically pleasing. This discussion will focus on inwall and in ceiling speakers for interior areas. Here are a few guidelines for speaker selection and placement:
1) Most speakers emit sound in a cone-shaped pattern. For the most even sound coverage in rooms with low, flat ceilings, inwall speakers will work better than ceiling speakers. You can often cover more area by using inwall speakers. For example, inwall speakers in a Foyer may provide coverage for an adjacent Dining Room and formal Living Room. However, the more speakers you use, the more even the coverage.
If aesthetic concerns outweigh performance concerns, ceiling speakers are a good comprimise. Ceiling speakers will also work well in rooms with high ceilings, or rooms that do not have the proper wall space needed for inwall speakers.
2) In general, larger speakers have better bass response. In larger rooms and critical listening areas, it is better to go with a larger speaker. Less critical areas, such as bathrooms, hallways, secondary bedrooms, etc., can usually be covered satisfactorily with smaller, less expensive speakers.
3) The interior finish of each room should also be considered when selecting speakers. Rooms with hard surfaces, such as tile or hardwood floors, are acoustically "bright". The reflected high frequencies (treble) become more apparent, and can make a speaker seem to have less bass output. Area rugs, overstuffed furniture, and draperies can help compensate for this. For these types of areas, a speaker with more bass response, or a full-range speaker, rather than a 2-way or 3-way design, can help achieve a more natural tonal balance.
4) When it comes to placement, it is best to place inwall speakers on the same wall of a room, six feet or more apart. Optimum height is ear level, but inwall speakers are usually placed closer to the ceiling for aesthetics and furniture placement. Locating them close to an adjacent wall will also enhance bass response. It is best not to position a speaker close to any one seat where possible. Ceiling speakers hould be placed along the center line of the room, six to twelve feet apart.
5) There are also some specialized speaker types to consider. A subwoofer/satellite configuration is a 3-piece system with a woofer that can be placed low on the wall, near a corner, and small satellite speakers, handling the midrange a high frequencies, that are placed in traditional locations in the wall or ceiling. The sub/sat system can provide great sound quality with the improved aesthetics of small speakers. For small, secondary rooms, like bathrooms and hallways, a single-point stereo ceiling speaker combines the sound from the left and right channels into a single package. This is accomplished with a dual voice coil woofer and two coaxially mounted tweeters. This provides stereo sound from a single speaker.
Control SystemsIn addition to local volume control, control of source equipment from other areas of the home is a convenient option. An IR remote repeater allows the use of infrared remote controls from other rooms. A target IR receiver is installed in the wall or in a cabinet and wired back to the main equipment location. IR emitters re-transmit the remote signal to the source equipment. All remote control functions that can be controlled at the equipment location can be controlled from rooms with a target IR receiver.
Wall keypads are a convenient way to control source equipment from a remote location without having to find your remote. Most multi-zone systems utilize keypads to control source selection, volume, and source control in each zone. Some keypads are proprietary, and only work with specific distributed audio systems. Other keypads are programmable, and work with a variety of systems. Many of these systems integrate with other home automation sub-systems to control lights, security, intecom, HVAC, etc.