Introduction This unit is concerned with the tools required to perform music, namely musical instruments. When you see the term musical instrument, you probably automatically think of the instruments found in an orchestra such as the violins, trumpets and flutes. Maybe you think of keyboard instruments like the piano or the organ. Or perhaps you visualise more modern instruments such as the electric guitar or the electronic synthesiser. You may even think of the human voice. These are all certainly
10.4 Summary The decibel (symbol dB) is a way of expressing a ratio. It is based on logarithms, and so adding decibels is equivalent to multiplying their corresponding ratios. Decibels can be used to express absolute values by referring them to a reference value. A common use of decibels is to express ratios of amplitudes. For instance, the amplification (or gain) of an amplifier can be expressed either as the ratio of the output and input amplitudes, or as a certain number of decibels. With a multi
10.3 The decibel as a measure of sound amplitude As I mentioned earlier, because a decibel is a way of expressing a ratio, it cannot by itself express the absolute size of anything. To express absolute values it must be referred to a fixed reference quantity, against which whatever is being measured can be compared. In the context of acoustics the reference used is the lower limit of audibility – the threshold of audibility. This varies from person to person, but has a nominal value that can be expressed as a pressure wave with an
8.3 Summary A fundamental musical and acoustical relationship is the octave. Pitches that are one or more octaves apart are heard musically as different instances of the same sound. A one-octave increase in pitch corresponds to a doubling of frequency. For musical purposes, a pitch range of one octave is divided into discrete steps, known as scales, the individual pitches of which are given letter names (A, A
8.1 The octave sound One feature of pitch that seems to be universal to all cultures is that for musical purposes the pitch range is divided into discrete steps: for instance, the notes of a scale. This is not to say that musicians rigidly adhere to those steps when they play, but the existence of such steps is fundamental to the way music is conceived and organised. Different cultures have different ways of defining the steps in their scale of pitches, but nearly all cultures take the octave as their starting po
7.2 Summary Pitch and loudness are subjective properties of sound. Pitch is closely correlated with frequency, and loudness is closely correlated with amplitude. However, under certain circumstances, slight changes of pitch can be created by changes of amplitude, and changes of loudness can be created by changes of frequency. The ear's uneven response is part of the explanation for these latter phenomena. In the pitch standard known as concert pitch, the note A4 (the A above middle C) is set t
7.1 The subjective experience Two of the properties of sound that we have examined from an objective stance, frequency and amplitude, have a fundamental importance to our appreciation of sound and music. In this section I want to look more closely at the subjective interpretation of these two properties of sound. I should stress that I am talking about sine-wave sounds in this section. The complex, non-sinusoidal sounds encountered in music add extra layers of complexity to the relationships I am discussing here. Ke
6.2 Practical units of amplitude The amplitude of a sine wave is measured in whatever units are used to calibrate the vertical axis, as you saw in connection with Figures 18 and Author(s):
Introduction This unit contains material that is essential to learning about music technology. Here you will explore the concept of sound and be introduced to the physics behind travelling pressure waves as the physical manifestation of sound. You will also learn about the subjective perception of pitch and loudness, in particular their relationship to frequency and amplitude. This unit is an adapted extract from the Open University courseAuthor(s):
7.2.2 Trap 2: the impoverished rich picture A distinguishing feature of rich pictures that turn out to be useful seems to be they are just what they say they are, rich. If I take usefulness as the criterion, the useful rich pictures are the ones bursting with interest and activity. They don't seem to tell a single story, there are lots of stories going on simultaneously. They reveal stories you didn't consciously build into them. How is such a rich picture to be achieved? Use everything you find in the situation. This means
7.1 Introduction The last activity was a demanding task. People I asked to do it during the writing of this unit, found it took a lot of concentration but it brought up lots of ideas, feelings and suggestions for action. Most of them were also concerned their rich picture might not be good enough. I imagine you will share some of these reactions. If you share any of these concerns, remember there are lots of ways of drawing a good rich picture and almost all rich pictures can be improved. Improving your rich
6 Part 2: 2 Immersing yourself in complexity The first three activities in Figure 4 are to plan a strategy, then to immerse yourself in an example of complexity, and then represent that complexity through drawing a rich picture. I've selected a rich picture as the focus of this task because it is a means of bringing you into a r
Part 2: 1 Introduction I have a number of purposes in mind as I write Part 2. You can read these in conjunction with Figure 4. 2.5 Review The title of this unit could have been Juggling with complexity: searching for system. This title seemed to capture something essential about the unit. Juggling is a rich metaphor and will be used explicitly in Part 3. But it also carries the idea of a skill that needs to be practised and that might seem incredibly awkward to begin with. You may find this idea helpful as you review your work in Part 1. Juggling is also a skill that, once practised, becomes second nature. This too may b 15 Part 2: 6 Key points of Part 2 Individuals are motivated to invent by one or more factors: curiosity; constructive discontent about a product; a desire to help others; a desire to make money. Organisations invent for a number of reasons: business strategy; the need to improve existing products and processes; new materials become available, as do technologies and manufacturing processes; government policy, legislation and regulations. The process of invention 4.3 Who invented the telephone? The popular image of Bell inventing the telephone, while it has some truth, is by no means the whole story. The two most significant players in the invention of a practical working telephone were Bell and Elisha Gray. Gray was the co-owner and chief scientist of a company that manufactured telegraphic equipment. Bell's patent description had sound transmission as a minor purpose. But Gray's caveat declared that the main purpose of his device was ‘to transmit the tones of the human voi 1.1.1 Diagrams are all around us We all try to make sense of the world around us. This sense is displayed in two ways. We all have our own ‘internal models’ of how things work based on our experiences and our interpretation of those experiences. These ‘internal models’ shape our thoughts and actions and lead us to expect certain outcomes from certain activities. They change and evolve with new experiences or (hopefully) when challenged by new information. They are the means b 1 How to use this unit This unit is a learning resource. Like all resources, there are different ways to use it depending upon what you are trying to achieve. Whatever you are trying to achieve it is important that you not only read the text thoroughly but also undertake the Activities (there are no ‘set’ answers to these Activities as they are personal to you but I have provided my own, or other people's, responses). After all, this is a unit that helps with systems thinking and practice, and wit Learning outcomes After reading this unit you should be able to: appreciate diagrams as a powerful aid to thinking and acting; distinguish between systems diagrams and diagrams helpful in systems work; demonstrate sufficient skills to ‘read’ and ‘draw’ a wide range of diagrams, following given conventions, that help improve your understanding of a situation; select diagrams suited to the needs of the situation you are investigating and the purp Acknowledgements The content acknowledged below is Proprietary (see terms and conditions) and is used under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence. Grateful acknowledgement is made to the following sources:
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