Harpsichords and spinets are mechanised members of the plucked string family and it is well known that the major problem with these instruments is that it is difficult to make the sound vary in loudness.
In the harpsichord the problem is partly solved by having more than one keyboard, each playing an instrument of different loudness. But if, instead of using the keys to pluck a string, we use them to hit the string, some variation is possible, as in the clavichord. It is with the piano, however, that the full range of loudness is possible, and indeed the modern piano is a most extraordinary piece of mechanical engineering.
Any one learning to play a keyboard instrument has to practise scales and this is often regarded as the most boring part of the learning process. The origin of musical scales, however, is quite fascinating. They have often been likened to the grammar of music since they tend to emerge only after primitive compositions have been played or sung for a long time.
Our concern will be mainly with a problem that arises with all keyboard instruments - it is impossible to play scales in all the different keys exactly in tune and a compromise is needed. Fortunately the synthesizers that form the main material of this last lecture also provide us with convenient ways of demonstrating the problem and its solution.
The extraordinary world of synthesizers and computers has developed explosively in the last few years. One could call an electronic organ a synthesizer though of course it does not have the enormous flexibility of recent synthesizers.
Classification is difficult but broadly speaking one can trace a line of development from electronic organs to analogue synthesizers,because in both we start with purely electronic oscillations and then add, subtract, multiply, mix and perform many other functions to make up the complex sounds of useful music.
A second line of development involves digital processing in which even the basic sounds are
