Home Theater Speakers - Size, Science & Sensitivity
Home theater speakers give a voice to your system. Although a large display screen looks impressive mounted on the wall, the movies you watch would be nothing without good audio. What’s the point of being able to see a historical battle scene in glorious Technicolor if the cannon-shots don’t make you jump? This is why you should spend time and money on your home theater speaker system. It’s even worth wading through the technical terms, which is why this page explains some of the most common phrases along with giving a little advice. (See our page on reviews for more jargon-busting.)
It’s best to buy your speakers as a whole set, rather than trying to assemble a home theater audio system out of pieced-together speakers from different manufacturers. Speakers work as a team, and they’ll be a tighter team if they’re designed as a set. That means better sound quality for you. There’s advice on where to place your speakers in our sections on setting up your home theater and adapting your home.
Home theater speakers: size matters
When you’re working out how to integrate your home theater system into a room of your house, the main consideration is the shape and size of the equipment. Speakers come in various shapes and sizes, so you can choose according to your budget and the space available. For example, it’s possible to buy floor-standing speakers the height of a grown man, but this might not be practical in a smaller room.
At the other end of the size scale, you can buy slimline speakers that are designed to fit in with the trend for flat-screen TVs. The only disadvantage of the new slimline speakers is that their bass output isn’t as good as that of bigger speakers. However, the technology is advancing so fast that it may only be a short time before that changes.
As a general rule, size and sound are related: big for bass, small for squeaky. If you’re on a mid-range budget, you won’t be able to get away without having a floor-standing bass speaker (also known as a subwoofer). Subwoofers are usually too big and heavy to put on a bookshelf. As for the other speakers, these can be wall-mounted or put on a shelf. However, when we talk about “bookshelf speakers”, that doesn’t necessarily mean speakers kept on a bookshelf – it just means speakers that are small enough for you to do so. Bookshelf speakers usually handle high and mid-range frequencies, as do wall-mounted speakers.
Your home theater audio: the science bit
There’s a reason why the pitch of the noises that come out of your speaker is linked to its size. It’s to do with the drivers – the cone-shaped part of the speaker that sits behind the grille. A larger driver (also known as a woofer driver) handles lower frequencies. A smaller driver (also known as a tweeter driver) handles high frequencies. Mid-range drivers handle frequencies between the two. It’s to do with sound waves; higher frequencies require the driver to vibrate faster, and smaller drivers are better at moving quickly. Similarly, lower frequencies require slower vibrations, and larger drivers are better at doing this. If it helps, think about how rapidly a shrew moves when compared to an elephant. If that doesn’t help, just think “smaller is speedier”.
Why sensitivity is important for home theater speakers
The sensitivity of a speaker measures the volume of noise it produces in relation to the amount of power it’s given. It’s usually measured in terms of the decibels (dB) a speaker produces with one watt of power, measured at one meter’s distance. The more sensitive a speaker is, the less amplification it needs to reach a given volume. Most users agree that a high-sensitivity speaker has sensitivities of above 90 decibels. Below 89 decibels, a speaker is low-sensitivity.
In our page on home theater receivers, we explained that the WPC, or watts per channel, of a receiver is important, but that you also have to consider other factors. One of those factors is the sensitivity of your speakers. The higher the sensitivity of your speakers, the less you need a high WPC. Many mid-range and high-range receivers have a WPC of over 100, but with high-sensitivity speakers, your home theater probably won’t need more than 70 WPC.