Shelf stereos, also known as compact or micro stereo systems are home stereo entertainment systems that can be conveniently situated in a variety of locations, most popularly, a living-room or bedroom shelf. They are designed to be small but also to be powerful enough, and of high enough quality, to provide full stereo music entertainment for the home.
What a Typical Shelf Stereo System Consists Of
Shelf stereos consist of a main unit that sits neatly between two matched loudspeaker cabinets plus an infra-red remote control for operating the stereo. The central unit may be a single unit comprising the main 'receiver' plus various internally connected audio players, all housed in the central unit. Alternatively, the various components may be separate stack mounted units. Depending on the manufacturer and the model, a modern shelf stereo system may comprise some or all of the following components.
The receiver is the controller of the whole system. All inputs, either from external sources or on-board players, are fed into the receiver, which processes, amplifies, and equalises the audio signals as necessary. Outputs, too, are fed from the receiver to the loudspeakers or to other external devices via the included output channels. Both the power and quality of the whole system are determined by the power and quality of the receiver. Typical inputs include: microphone channel, line-in or aux channel plus digital inputs, such as USB port and SD card slot. Output channels can include: left and right channel stereo speaker outputs, video out, headphone socket, line out socket, and USB digital port
CD and DVD Player
The player will be designed to be compatible with the usual array of common CD formats. Some models also support DVD formats. Formats supported will be specified in any advertising material. Audio playback is delivered via the shelf stereo's loudspeakers or headphones, while DVD video content (if supported) can be fed from the shelf stereo's video output to any suitable television or monitor. The CD player may also have an auto changer mechanism to enable uninterrupted play of several discs loaded together.
A digital AM-FM radio tuner will be included. These normally have a large range of tuning presets, typically amounting to between 20 and 40 user-adjustable presets. Look out for advertised features such as DAB (digital audio broadcasting) and satellite radio if radio reception is an important requirement.
Radio Alarm and Timer System
Shelf stereo systems have a clock displayed on the front LCD panel. Advanced alarm features may be included too. These enable the alarm timer to sound a buzzer or to play the radio or a CD at the selected time. Expect all the usual digital alarm functions, such as 'sleep function', which allows a few minutes more of silence before coming on again. Gradually increasing alarm volume is also a popular alarm function. Timer functions are also available, and some people find these features useful enough to justify keeping their shelf stereo in the kitchen. Complex time schedules needed for cooking elaborate meals can easily be overseen with the stereo's timer functions.
Docking and Audio Player Inputs
Many modern shelf stereos include docking facilities to allow an iPod or iPhone to be 'docked' and played through the system or to be recharged. MP3 players can also be directly connected to provide another digital audio source.
Many shelf stereos offer preset equalisation controls. These settings alter the frequency response of the stereo to better match the frequency characteristics of certain styles of music. Some shelf stereos include a user controllable graphic equaliser. Graphic equalisers offer the ultimate in tone control. Increase or decrease any parts of the audio frequency response at will for an overall tone level that best suits any particular music being played.
Cassette Player and Turntable
Some shelf stereo systems include either of these obsolete features as retro-style extras for those who have a lot of music on compact cassettes and vinyl discs. Most shelf stereos are front-loading and facing. That's what makes them suitable for placing on shelves. Those with a turntable, however, need to be top-loaded and placed on a lower shelf to allow easy record changing and stylus placement.
The supplied loudspeakers are separate units that are designed to be placed on either side of the main unit. They can be placed anywhere, however. Speaker extension cables will be necessary if they're taken any distance from the main unit. Note that excessive distances from the main unit will require much longer extension cable, which may reduce the power levels available to drive the speakers.
An advantage of buying a shelf stereo is that the manufacturers will have ensured the best possible electrical matching of the loudspeakers with the rest of the shelf stereo system. The shelf stereo's specifications will normally provide full technical information on the loudspeakers' construction, frequency response, and power handling and matching capabilities.
Printed specifications are supplied with every new shelf stereo. Advertisements of particular shelf stereos will also publish some of those specifications, especially those at which it excels. The two main 'quality' specifications of stereo systems refer to power output and frequency response of the receiver's amplifier as well as the included loudspeakers.
Traditionally, small stereo systems were modestly-powered and unable to match the power and quality of larger home stereo systems. Not only was it impractical, at first, to make them more powerful, but even if those problems were overcome, loudspeaker technology wasn't advanced enough to enable small loudspeakers to handle large power outputs, especially where bass frequencies were prominent. Advances in miniaturisation has gradually eliminated most of those power and quality limitations for shelf stereos and their loudspeakers, and a power output rating as high as 500 watts isn't that uncommon nowadays. Note that there are different ways of measuring power, such as maximum peak power rating or RMS power rating, which is more of an average rating, so always try to compare 'like with like' when comparing the power output of any stereo system.
If any shelf stereo advertises its power rating as 'total power', it's normally referring to the power consumed by the whole shelf stereo system rather than the stereo's output power. While the total power rating may give some idea of what the shelf stereo costs to run in terms of electricity used, it says nothing about how loud it will sound. It's necessary to know the output power, preferably as an RMS (root mean square) value, which will always be a lot less than the total consumed power.
Music consists of a wide range of frequencies, from low bass tones to high-pitched treble tones, and a good stereo system has to be able to reproduce those high and low-pitched tones equally well. The frequency response of the stereo, which is usually shown in the specifications as a graph, shows how well the stereo can reproduce frequencies, wherever they lie in the audio spectrum.
Normal human hearing has a frequency range of from 20 herz (vibrations per second) to around 20,000 herz. If a particular stereo unit's frequency response falls short of those limits, those extreme frequencies in the music will either be missing or severely reduced. A shelf stereo with a frequency response that exceeds the entire audible spectrum will be able to produce the highest and lowest audible frequencies with greater power and clarity.
How to Find a Shelf Stereo on eBay
Finding a shelf stereo on eBay isn't difficult as many are available on the site and more are added every day. Keep in mind, however, that some individuals and companies selling them may list them ascompact stereos or micro stereos rather than shelf stereos. That means that all three of those are useful search terms that can be entered into eBay UK's internal search engine to produce a list of suitable results. eBay's convenient category system enables searches to be made that are highly specific. These can be seen clearly displayed on the left-hand side of the pages containing the listings.
The Sound & Vision category is the main category containing the greatest number of shelf stereos. The accompanying filtering check-boxes enable the search to be as specific as required. They make it possible to deliver search results according to, for example, how expensive they are, whether they're new or pre-owned, or whether they're being sold as an auction item or directly as a Buy it Now item. Many more selectable options are available.
Although shelf stereos aren't new, they have distanced themselves from their earlier versions by incorporating far more connectivity features. Docking capability and digital and analogue inputs and outputs make for home stereo systems that offer far greater flexibility and functionality. Their future seems assured as their popularity is showing no signs of waning.