We've already mentioned that a room's size can have a fundamental impact on the size and type of loudspeaker you should buy now. We'll explain why surround sound speaker placement is so important.
The moving parts in a speaker are called drive units, because they work to ‘drive’ the air in your room. The larger the loudspeaker and the larger its drive units, or in some cases the more drive units it employs, then the more air it can move. This is relevant to speaker placement, because the larger your room, the more air your speakers will be asked to move and as a result the harder they'll have to work. To use the most extreme example, the tiny drive units fitted to most desktop speaker systems would sound lost in a large concert hall. By the same token, a massive pair of floorstanders will excite too much air in a small space, sounding both sonically and to a surprisingly real extent, physically intimidating.
For that reason, choosing speakers of an appropriate size to fit your available space is a significant step towards better surround sound. That means being realistic not only about the room you have available, but also about where you can actually position your surround speakers within that space. If you have to place your speakers close to a wall, or a corner, you might find your buying choices are more limited than you'd first hoped.
Why? Every loudspeaker will interact with its environment and especially with nearby walls. Place your speakers close up to a back wall and you'll find the level of bass on offer increases, but this can be at the expense of openness, stereo imaging and 'speed'. Bigger speakers will simply worsen this effect, sounding bigger and more bass heavy than ever. Conversely, place small speakers too far out into the room, and they can sound lost, again because they're being asked to drive too much air. For that reason it’s vital you plan where you intend to put your speakers before you buy, taking account of the specific space requirements of each model relative to your room. The exact science of positioning can vary from speaker to speaker, often being influenced by cabinet design, but most manufacturers and dealers will be able to give you guidelines. One hard-and-fast rule almost everyone will agree on is that corners are a definite no-no, as they cause significant amounts of boom that no amount of high-quality amplification and source kit can overcome.
The acoustics of your room can also influence sound in other ways. Place your speakers on a hard, polished floor, and you'll find the sound takes on a significantly different character to the results you'd get from a warmer, softer, carpeted room. This is caused by sound reflections, a minimalist modern room is more acoustically live than one awash with soft furnishings. It is immensely difficult for your dealer to compensate in for this effect in a typical demonstration area, but its worth mentioning the particular properties of your living room to him just the same, he may be able to recommend kit that can compensate for its acoustics.