The Beosystem

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- for the sake of good music, logically

In the 1970s a new form of hi-fi system - the Beosystem - came about as a result of Bang & Olufsen's search for hi-fi perfection by the blending together of compatible units - from receivers to cassette-recorders and from integrated record decks to passive loudspeakers - both aesthetically and in terms of performance and price. Many may argue that Bang & Olufsen's first true music system was the Dirigent system of 1962 or even the Beosystem 1200 that followed a few years later. However, the idea didn't truly gain ground until well into the 1970s. The Beosystem lasted well into the 1990s when more individualistic products took over. Not that one couldn't 'mix and match' with a Beosystem - they were 'created' as merely a guideline. Ultimately the choice, as ever, was that of the consumer's. We are all accustomed nowadays in seeing 'off the peg' products. However, the Beosystem was the first bespoke amalgamation in hi-fi. This is its story.

The following extract is taken from the 1974 Bang & Olufsen catalogue on music systems and provides a glossary of what true high-fidelity sound, in the eyes of Bang & Olufsen, is all about. Although written nearly thirty years ago, it gives the twentieth-first century view of providing high-fidelity - for the sake of good music.

"Today, music has become an important feature of everyday life for a growing number of people. It is sheer lunacy to suggest that one should be able to read and write music in order to appreciate it fully. Just so with electronic high-fidelity equipment. Products should be designed and constructed so that they can be operated by people without engineering degrees. A child. A housewife. The most impractical bachelor. All members of the family should be able to operate high-fidelity equipment with ease. To limit the functions of its products to the essential and to develop logical operation facilities to execute these functions, are two of Bang & Olufsen's key jobs. But what constitutes logical operation? It is largely a matter of asking whether the number of buttons and knobs which we often see is a real necessity towards fulfilling the simple wish for music at home. Naturally, the answer is sometimes no. By thinking carefully about what equipment is necessary and the quality each unit ought to have, you will discover that, although you are a music lover, your home need not look like a sound laboratory. It is impossible to give a detailed explanation in these few pages. However, we have tried to give a general guide and present basic facts which we feel you ought to know before you invest in the high-fidelity system you hope to enjoy long into the future.

The high-fidelity norm: its relevance and its use. The DIN 45500 high-fidelity norm is a set of rules which establish the minimum demands a product must fulfil before it can be called "high-fidelity". These rules include not only standards but also describe measurements upon which technical data must be based. The measurements are of interest to you because they help you to evaluate and compare the products of several manufacturers before you choose to listen to them. Obviously, you need not master technical details in order to listen to music. Technique is the means, not the aim. The high-fidelity norm and its basic data provide a background from which to begin. Use this knowledge now but forget it when you listen to music.

The frequency range: the limits of audibility. Our sense of hearing permits us to experience certain sound modulations, which we call the audible frequency range. The high-fidelity norm states that a sound system must be able to reproduce a range of sounds between 40 - 12,500 Hz per second without discernible changes in the level of sound power. Variations in sound level are expressed in dB, decibels. The lower the dB figure, the better.


The correct name is 'harmonic distortion'. It expresses how much unwanted overtones (or harmonics) of a basic tone are audible. Harmonic distortion is measured in percentages. The lower the figure the better the sound quality. All musical instruments and voices have a basic tone and a number of harmonics which determine their characteristic timbre. Naturally these overtones must be present in the reproduction of sound.

Dynamic range

How important is high power output in an ordinary living-room? Sitting in a concert hall, you can hear that the sound intensity from the various musical instruments varies all the time. The difference between the loudest and the softest passages is called the dynamic range and should be retained during reproduction at home. Luckily only very few of us have a living room which is the size of a concert hall, otherwise an amplifier with several hundred watts power output would be necessary! In the following, we present Bang & Olufsen products which have a power output of between 15 and 60 watts RMS per channel values which are ample in a normal sitting room. The dynamic range is thus the ratio between the strongest and the weakest passages but it is also related to another term often used in audio specifications: Signal-to-noise ratio, i.e. the ratio between the desired amplified sound and the noise inevitably produced by electronic components. A low signal-to-noise ratio means that the weakest passages will be drowned in noise. This measurement is stated in dB. The higher the figure, the better.

Transient response

High-fidelity equipment must be able to meet all musical demands. Transient response is characterised by a short sharp sound of high intensity. It might be a hard intonation on a grand piano or the note from a triangle! Transients place demands on an audio system, not least on the loudspeaker. These sounds consist of tones in the treble area. A high quality audio system is characterised when these transients are not reproduced with a blurred image. Each high pitch instrument must come through clearly and transparently as the original, the reality.

Why four loudspeakers when you have only two ears?

The majority has accepted that stereo reproduction with two loudspeakers gives "correct sound reproduction. So why four loudspeakers? In order to understand this we have to look at the various sound reproduction systems - their advantages and their disadvantages.

Mono - monophony

Mono or a one channel sound system is the original form of recreating sound in radio, on records or on tapes. Mono can offer high-fidelity reproduction since we can transmit a wide range of tones with low distortion and a good dynamic range.

Stereo - stereophony

Stereo or a two channel sound system improves the sound experience with two loudspeakers at reproduction. The sound picture "widens" so that we can localise various instruments and experience the breadth of the orchestra. The illusion of "being there" in the concert hall becomes greater.

How can one ascertain the maximum integrity of a high-fidelity system?

A high-fidelity system consists of several units. A radio with built-in amplifier and a pair of loudspeakers is the simplest audio system. 'Beosystem' is Bang & Olufsen's name for a high-fidelity system in which the units are matched in technical design so that they form a harmonious whole. By choosing a recommended Beosystem you are certain of an optimum solution in terms of performance-to-cost ratio. But naturally the suggested Beosystems are guides only, as all units may be purchased individually. The choice is yours and depends on personal factors."

Created: 12th January 2007
Modified: 6th April 2007

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