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Time: 20 hours
Level: Introductory
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 Introduction Resource- 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...
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| | 1 Aims of Creating musical sounds | |
| | 2 What is a musical instrument? | |
| | 3 Sound production in musical instruments
- 3 Sound production in musical instruments Resource
- Musical instruments come in all shapes and sizes and produce an enormous variety of different sounds. Yet, with the exception of certain electronic instruments, the basic physical principles by which sound...
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- 4 Excitation Resource
- For a player to be able to sound a musical instrument, there must be a means of inputting energy to set up the vibration. This energy may be introduced in a short, sharp burst or continuously over a period...
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- 5.1 Standing waves Resource
- You learned earlier that when a musician plays a note on an instrument, they supply it with energy that causes the primary vibrator to oscillate at certain specific frequencies. In Section 5 we are going...
- 5.2 Vibrating string: speed of wave propagation Resource
- If standing waves are set up when two travelling waves moving in opposite directions interact, then how are standing waves set up on a string and why are they set up only at certain frequencies?
- 5.3 Vibrating string: standing waves on a string Resource
- We still haven't answered the question of how standing waves are set up on a string. To do so we need to return to our string, fixed at one end and held in someone's hand at the other end. Imagine now...
- 5.4 Vibrating string: normal modes of vibration Resource
- The frequencies at which standing waves can be set up on a string are the string's natural frequencies. They can be determined quite easily. The first thing to note is that the end of the string being...
- 5.5 Vibrating string: pitches of notes produced by stringed instruments Resource
- When a string is bowed, plucked or struck, energy is supplied that starts the string vibrating. The string doesn't just vibrate in one single mode; instead, it vibrates in a combination of several modes...
- 5.6 Vibrating air column Resource
- You learned in the previous section that for standing waves to be set up on a string there must be reflection. A travelling wave reaches the end of the string and is reflected. This results in a second...
- 5.7 Vibrating air column: reflection at the end of an air column Resource
- When a sound wave reaches the end of an air column, it is clear that it will be reflected if the tube end is closed. You only have to imagine yourself standing some distance, let's say 50 metres, away...
- 5.8 Vibrating air column: standing waves in a cylindrical tube open at both ends Resource
- The frequencies at which standing waves can be set up in an air column enclosed by a cylindrical tube that is open at both ends can be determined quite easily. Because both ends are open to the atmosphere,...
- 5.9 Vibrating air column: standing waves in a cylindrical tube closed at one end Resource
- We'll now turn our attention to the setting up of standing waves in an air column contained within a cylindrical tube that is open at one end but closed at the other. Straight away we can say that the...
- 5.10 Vibrating air column: end effects Resource
- In the previous two sections on standing waves in cylindrical tubes, we assumed that at an open end there must be a pressure node. In fact, the pressure node (and the corresponding displacement antinode)...
- 5.11 Vibrating air column: standing waves in a conical tube Resource
- The third configuration of air column that we shall consider is that enclosed by a conical tube. Figure 17 shows the normal modes of vibration for a conical tube plotted in terms of pressure. As you would...
- 5.12 Vibrating air column: pitches of notes produced by wind instruments Resource
- In a wind instrument, the air column is the primary vibrator. To excite the air column, a musician either blows across it (e.g. flute) or blows down it via a mouthpiece (e.g. trumpet) or reed (e.g. oboe)....
- 5.13 Other primary vibrators Resource
- You saw in the previous two sections that stringed instruments and wind instruments possess primary vibrators that have harmonically related natural frequencies. As a result, these two classes of instruments...
- 5.14 Response and damping Resource
- You have learned so far in this chapter that when a musician plays an instrument, they force the primary vibrator to vibrate. If the primary vibrator is driven at one of its resonance frequencies, the...
- 5.15 Summary of Section 5 Resource
- It is probably worth summarising some of the main points you should take away from this section on primary vibrators. The first thing to remember is that when an instrument is excited, it vibrates strongly...
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- 6 Radiation Resource
- All the primary vibrators we discussed in the previous section can to some extent communicate vibrations to the surrounding air and hence radiate sound. However, some radiate sound better than others....
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| | References and Acknowledgements | |
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