In this article we will learn:
- How speakers classify according to their function & size.
- A few words about how speakers placement can enhance the sound
- & about wires and connectivity.
- A few details about installing a home theater system.
Speakers size & function
According to enclosure sizes & functions there are five types of speakers:
- Floor-standing
- Bookshelf
- Subwoofer
- In-Wall & in-ceiling
- Outdoor
Floor-standing speakers, also known as tower speakers, have been around for quite a while. They are the largest type of speakers, reproducing a wide range of frequencies, including deep bass, they are more efficient and usually stand on the floor, whereby their name.
Concerning design, floor-standing speakers tend to occupy more space. Given a smaller room, one can choose from the many "slim tower" models available.
Bookshelf speakers are of use when the space is tight and you also care about lowering costs. The boxes are smaller and they can be placed on stands or on shelves. They are almost always two-way, and can output an overall, accurate stereo sound, but not as low bass frequencies as tower speakers. That is why in home theater systems, a powered subwoofer is added.
Subwoofer/satellite systems
Instead of having a lot of space occupied by speakers, you can choose a combination of satellites and a suboofer. The satellites have more advantages because they are so small and can be placed virtually anywhere in the room. They deliver rich, full sound but can handle only high and mid-frequencies.
The subwoofer unit is much larger. Because the sound spreads out omni-directionally, there's no much limitation in where to place it.
In-wall and in-ceiling speakers seemed not long ago to be useful exclusively in the area of commercial applications. However, in the latest years there have been many changes in design trends and tastes, and many home arrangements include this kind of speakers.
In-wall speakers are not different from shelf-speakers, and the wall-frame they are mounted in replaces successfully the speaker cabinet.
In-wall speakers are full range but a powered subwoofer can be added for low bass frequencies.
The greatest thing about in-wall/ in-ceiling speakers is they fuse with the decor, mastering the aesthetics of the room. However, the sound quality and efficiency is lower than that of normal speakers, because of the wall, which doesn't have the acoustics of the usual speaker-cabinet. The major drawback is about installation: wires need to be run behind walls, which may not always be possible.
Outdoor speakers - a few tricks
The best outdoor speakers are certainly bigger than any of the previous types, develop greater power and are water-resistant. At least that's what most manufacturers say. Yet, they recommend placing the speakers in a location that is less exposed to rain. Speakers cone slightly facing down is preferred for drainage.
When mounting outdoor speakers, one must keep in mind the amount of background noise to be covered (wind, traffic etc.)
Tips on outdoor speaker placement:
- placing the speakers near a wall: improves bass output
- mounting the speakers higher: the sound travels farther, and the quality is better.
- try not to run the wire through doors or windows, but through walls, in order to avoid accidents (a door-slam can damage the wire);
- speaker placement directly on the ground is not recommended;
- theoretically, speaker-wires should not disturb the reunion attendants.
Speaker placement inside the room
The placement of the speakers inside the room is not only about the aesthetics of the arrangement, but mostly about acoustics optimization.
First thing to do is try to put yourself or, if possible, your audience in the center of the audio area. In a stereo system, the speakers and the stereo should create a triangle with the audience placed in the center. This center should have the best possible acoustics, just like trying to recreate a complete image by overlapping two negatives of different tonalities. That's what we call imaging. In a home theater system, imaging is the tridimensional efect of the sound.
When the speakers are placed outside, focus is easy to obtain. But things are different inside.
The walls reflect the sound waves. When we listen to music inside, we hear a mix of direct and reflected sounds. Some frequencies are reinforced, some are suppressed. Thus, the original sound is altered. In this conditions, attention is required towards the following aspects:
- Distance to the side and back wall: place the speakers as far from the walls as possible, but not less than 1-2 feet; this helps reducing early reflections (link to glossary); the distances from the side- and back-wall must be (most preferable) unequal;
- The distance among speakers: usually, increasing the distance between speakers widens the sound-stage up to a point, when the center image is broken; the speakers should be symmetrical to one another, if possible.
To sum it all up, the answer when it comes to best speaker placement is experimentation. An alternative to placement, when space inconveniences can't be surpassed, is tweaking the speakers set-up.
Wiring & connectivity
Most speakers don't include wires. The reason is that you buy the exact amount of wire you need for your home needs. On the other hand, choosing the right type of wire is often confusing.
First, it is important how thick the wire is. Thicker wires are better conductors, thus more efficient. On the other hand, thicker wire is more expensive. The wires are identified by their AWG number (American Wire Gauge), or just "gauge". The smaller the number, the thicker the wire. For speakers, most users recommend wire gauges ranging from 12 to 16. Anything thinner than 16 gauge is not recommended for home audio.
The speaker wire carries amplified signals from the amplifier's output to the speaker's input, where the signals are usually routed through a crossover and out to individual drivers. In order to carry the amplified signal, speaker wire consists of two leads, typically encased and bundled in plastic insulation — one for the positive signal, and one for the negative. Sometimes, the speaker wire is marked (+) and (-) to help the user distinguish the two leads — if not, there will be other way to tell them apart.
Connections to the amplifier:
- the five-way binding post - offers superior surface contact, solidity of connection and connection options;
- the spring connection (or guillotine connection) - usually found on less expensive speakers and receivers.
Installing a home theater system
Home theater systems include the following speakers:
- Front speakers, left and right
- Center channel speaker
- Surround speakers
- Subwoofer
Front speakers, left and right, are the main stereo speakers in the system. Floor-standing, bookshelf, and satellite/subwoofer speakers can be successfully used as main speakers in a home theater system.
The center channel speaker is crucial in the home theater system, because it reproduces almost 50% of the soundtrack information. The center channel must perfectly syncronize with the main speakers, as it also reproduces most of the voices and dialogues.
The center channel speaker is smaller, and placed above or on a shelf near the TV.
The surround speakers create the depth of sound by reproducing atmospheric and ambient sounds. They will be placed in the background of the audio field.
The powered subwoofer is able to reproduce deep bass frequencies and is usually placed to a side.