Hi-fi Speakers

Types

Wharfdale speakersTower Speakers: Also called floor-standing speakers, these have been around for years and are generally considered the gold standard for speakers.  Larger than other types of speakers, tower speakers are capable of reproducing a wide range of frequencies.

Bookshelf Speakers: These speakers are excellent for limited spaces or budgets.  These compact speakers are a suitable alternative to tower speakers.  Bookshelf speakers come in a smaller casing, so they fit easily on a small table or shelf; they offer superior performance in a small package and come with a reasonable price tag.

Centre Channel Speakers: Essential for a serious home theatre experience, these speakers are engineered to handle a stunning frequency range and deliver precise sound across the board - dialogue, special effects, soundtracks, action sequences, etc.

Surround Speakers: Small enough to fit in the palm of your hand, yet powerful enough to deliver brilliant performance in any home theatre, these speakers are compact, produce rich, full sound and can be mounted on walls, ceilings, shelves or stands.

Subwoofers: The sole purpose of a subwoofer is to deliver the low frequency sound that compact speakers miss.  Though subwoofers are usually quite large, the multi-directional characteristics of low frequency sound make it possible to tuck these speakers out of the way without compromising sound quality.

Sound Bar Speakers: Perfect for rooms that aren't well-suited to traditional speakers, sound bars can deliver full sound despite their compact design.  These speakers need very little floor space and provide virtual surround or enhanced stereo in a single package.

Integrated Speakers: These speakers can be installed directly into walls or ceilings.  Built-in, wireless speakers offer great sound in a stylish, inconspicuous design and are ideally suited for tight spaces.  These speakers are good for new construction or remodelling projects where holes can be easily cut in walls or ceilings to accommodate installation, are nearly invisible and provide ambient sound.

Outdoor Speakers: Outdoor speakers can help turn outdoor spaces into an extension of your home.  Durable outdoor wireless speakers are made to withstand the elements, so they will go anywhere in your garden or around your patio.  They are resistant to wind, rain, heat, snow and freezing temperatures, come in a variety of casings to match or blend into outdoor spaces and are loaded with power to function well in large, open spaces.

Personal Speakers: A must for those on the go.  Personal wireless speakers are highly portable, highly adaptable and deliver a surprising level of power and performance for their small size.  Personal speakers can be connected to a variety of audio devices including radios, CD players, iPod docking systems, MP3 players and portable DVD players.  Most personal speakers require just a set of batteries or a standard cable adaptor, with wireless speakers available for even greater mobility.

Active or Passive?

All speakers are either active or passive.  No matter what particular characteristics or specifications your speakers have - even if they are wireless speakers - they will fall into one of these two categories.  The only thing that determines a speaker's classification as active or passive is its relationship to the amplifier that drives it.

Most speakers are passive.  This simply means there is no integrated amplifier; the speakers must be connected to an external amplifier via a standard wire.  The wire makes it possible for the speaker signal to be amplified just enough to produce good quality sound.

Active speakers, however, have an integrated amplifier and are powered by a low-level signal that gets passed along a cable.  Because an amplifier is an electronic device, it has to be connected to a power source.  This means that an active speaker must be placed near an active electrical outlet.

Most home audio or theatre systems have just one active speaker - the subwoofer.  There is really no reason for most systems to have any others.  Active speakers are hard to find and very expensive.  They also limit your ability to select an amplifier that is tailored to your sound system.  Active speakers usually fall on either end of the price spectrum:  the low-end active speakers are meant to be used with a PC or portable MP3 player; the high-end models cost several thousand pounds each.  Unless you are building a public theatre or are a serious audiophile, passive speakers will meet your requirements quite capably.

Specifications

Sony bar speakerWe won't get too technical here, but it is important to mention a few specifications to help you learn more about how wired speakers and wireless speakers are rated and categorised.  Hopefully, this will make it easier for you to compare different models to find the right speakers for your audio system.

Enclosure: A speaker's enclosure is simply the outer covering in which it is contained.  While this may seem a largely cosmetic choice, the enclosure does affect sound quality.  The size of the speaker enclosure determines how much air moves through the device, which in turn dictates the amount of sound a speaker can throw into the room.  Always match the size of the enclosure to the size of your room - don't just buy the biggest speakers you can afford.  A large speaker has been designed to perform in a large room; it won't sound right in a small space.  Conversely, small speakers are meant for small spaces and won't perform well in a larger room.

Diaphragm: The type of material used on a speaker diaphragm can have a significant impact on performance, particularly the speaker's frequency range.  The diaphragm material often encroaches on the speed with which the driver moves, distorting sound as it moves through the speakers.  High-end speakers have drivers made from titanium or aluminium.  Less expensive materials like silk, paper and some plastics can produce great sound at an attractive price, so these are often used for mid-range and discount speakers.

Power Rating: This spec is defined as the continuous power and the short-term peak input power a speaker can withstand before it is destroyed - basically, testers measure how long a speaker can go at a constant high level of output before it dies, and how strong a blast of instant power is needed to fry it.  While most users rightly assume that a higher power ranking is better, it is possible to destroy a speaker with much less power than that of its peak rating if the speaker is subjected to prolonged periods of time where its continuous power handling limits are exceeded.

Impedance: In simple terms, impedance is the amount of resistance a speaker applies to an electrical signal.  The lower the impedance, the more power the speaker pulls from the amplifier.  A speaker with impedance that is too low for its connected amplifier is likely to burn out the amp in a fairly short period of time, as it will continually draw excessive amounts of electric power.  Impedance is measured in ohms; most home audio speakers should be rated at least six ohms, but no less than four ohms.

Frequency Response: Representing the range of frequencies or musical tones a speaker is capable of reproducing, frequency response is measured in Hertz (Hz), but also usually includes a decibel (dB) measurement as well.  The standard industry variance is ±3dB, which accounts for the fact that a speaker's frequency response is never absolutely consistent over the whole range of tones.  The goal is for a speaker to reproduce sounds at the same volume they were recorded (high highs and low lows), though this ideal is virtually impossible to attain.  Most speaker frequency response measurements look something like this:  20Hz - 25Hz +/- 3dB.  When you are shopping, you want that first number to be as high as possible and that second number to be as low as possible.

Magnetic Shielding: Magnetic shielding has been designed to reduce the stray magnetic fields that are generated as a result of the speaker's operation.  Stray magnetic fields can interfere with images on a television or computer screen and can even destroy data on certain media storage devices; speakers placed near these electronics can be very harmful.  When encased in special magnetic shielding, speakers can be put anywhere without worry that they will corrupt other devices or media.  This is particularly important for wireless speakers, as they are meant to be easily moved.