1

Critical bands by sine waves: Two sine waves are heard—one at a constant frequency (F₁) of 440 Hz and the second starting at 440 Hz, moving to around 660 Hz and back to 440 Hz. The changes described in Section 2.2 and illustrated in Figure 2.6 should be audible.

2.2

2

Average hearing change with age: The first few section of the chorale prelude used in Track 73 has been filtered to allow the average effect of aging, or presbycusis, to be illustrated acoustically for men and women aged (in years) 20 (no difference), 60 and 80 based on the data plotted in Figure 2.11. Track has five snippets: (1) male or female aged 20; (2) female aged 40; (3) male aged 40; (4) female aged 60; (5) male aged 60.

2.3

3

Loudness doubling: A doubling in loudness requires, on average, a 10 dB increase in sound pressure level as indicated in Example 2.4. This example uses an anechoic recording set to the following levels: 0 dB, +3 dB, +6 dB and +10 dB to illustrate the effect of doubling intensity (+3 dB), doubling pressure (+6 dB) and average doubling in loudness (+10 dB).

2.4

4

Pitch demo: Three pitch demonstrations are presented: (A) the first five harmonics with a fundamental of 200 Hz; (B) as (A) but without the fundamental (the “missing fundamental”); (C) a sound consisting of components at 1800 Hz, 2000 Hz and 2200 Hz for which the perceived pitch is usually 200 Hz.(D) a sound consisting of components at 1840 Hz, 2040 Hz and 2240 Hz for which the perceived pitch is usually reported as 207 Hz but with ambiguity. For explanations of (C) and (D), see comments in Section 3.2.1, Schouten (1940) and Moore (1982)—references listed at the end of Chapter 3.

3.2.1, 3.2.2 & 3.2.3

5

Prime partials: Synthesized sounds whose frequency components are set to prime numbers (557 Hz, 1381 Hz, 1663 Hz, 1993 Hz and 2371 Hz); thus they are not harmonics of a common fundamental.

3.2.2 & 5.3.1

6

Residue pitch: An arpeggio and a glissando are played using noise added to a delayed version of itself as described in the final paragraph of Section 3.2.6.

3.2.6

7

Tuning systems: A chord sequence (tonic—I, sub-dominant—IV, dominant—V, tonic—I) is played in just temperament (rooted in the key of C) in all 12 keys starting and ending in C major. Notice the difference between the consonant tuning in C major and the rather more dissonant tuning in keys such as F# and B major.

3.4

8

Half-size violin arpeggio: G major arpeggio (G3 to G5) on a half-size violin.

4.2

9

Half-size violin music: Brief music snippet on half-size violin.

4.2

10

Violin arpeggio: G major arpeggio (G3 to G7) on a violin.

4.2

11

Flute arpeggio: G major arpeggio (D4 to B6) on a flute.

4.3.3

12

Flute music: Brief music snippet on a flute.

4.3.3

13

Piccolo arpeggio: G major arpeggio (D5–B7) on a piccolo.

4.3.3

14

Piccolo music: Brief music snippet on a piccolo.

4.3.3

15

Bass recorder arpeggio: G major arpeggio plus extreme (F2, G2 to G4) on a bass recorder.

4.3.3

16

Bass recorder music: Brief music snippet on a bass recorder.

4.3.3

17

Tenor recorder arpeggio: G major arpeggio plus extremes (C3, D3 to B4, C5) on a tenor recorder.

4.3.3

18

Tenor recorder music: Brief music snippet on a tenor recorder.

4.3.3

19

Treble recorder arpeggio: G major arpeggio plus extreme (F3, G3 to G5) on a treble recorder.

4.3.3

20

Treble recorder music: Brief music snippet on a treble recorder.

4.3.3

21

Descant recorder arpeggio: G major arpeggio plus extremes (C4, D4 to B5, C6) on a descant recorder.

4.3.3

22

Descant recorder music: Brief music snippet on a descant recorder.

4.3.3

23

Sopranino recorder arpeggio: G major arpeggio plus extreme (F4, G4 to D6) on a sopranino recorder.

4.3.3

24

Sopranino recorder music: Brief music snippet on a sopranino recorder.

4.3.3

25

Swanee whistle: Fast and slow sweeps on a swanee whistle.

4.3.3

26

Bassoon arpeggio: G major arpeggio plus extreme (Bb1, B1 to B4) on a bassoon.

4.3.6

27

Bassoon music: Brief music snippet on a bassoon.

4.3.6

28

Oboe arpeggio: G major arpeggio (B3 to D6) on an oboe.

4.3.6

29

Oboe music: Brief music snippet on an oboe.

4.3.6

30

Bagpipe steady chord: Drone and steady note on bagpipes.

4.3.6

31

Bagpipe music: Brief music snippet on bagpipes.

4.3.6

32

Bass clarinet arpeggio: G major arpeggio (D2 to G4) on a bass clarinet.

4.3.6

33

Bass clarinet music: Brief music snippet on a bass clarinet.

4.3.6

34

Clarinet arpeggio: G major arpeggio (D3 to G5) on a clarinet.

4.3.6

35

Clarinet music: Brief music snippet on a clarinet.

4.3.6

36

Tuba arpeggio: G major arpeggio (G1 to G3) on a tuba.

4.3.7

37

Tuba music: Brief music snippet on a tuba.

4.3.7

38

Bird call: cuckoo (3 times).

4.3.3

39

Bird all: duck (8 times).

4.3.6

40

Bird call: goose (7 times).

4.3.6

41

Bird call: nightingale (5 times).

4.3.3

42

Bird call: quail (8 times).

4.3.3

43

Adult female speech: Read passage (both channels: microphone).

4.5

44

Adult female speech: Read passage (right: microphone; left: electrolaryngograph*).

4.5

45

Adult female arpeggio: G major arpeggio from B3 to B5 (both channels: microphone).

4.5

46

Adult female arpeggio: G major arpeggio from B3 to B5 (right: microphone; left: electrolaryngograph*).

4.5

47

Adult female singing: Song snippet (both channels: microphone).

4.5

48

Adult female singing: Song snippet (right: microphone; left: electrolaryngograph^*).

4.5

49

Adult male speech: Read passage (both channels: microphone).

4.5

50

Adult male speech: Read passage (right: microphone; left: electrolaryngograph*).

4.5

51

Adult male arpeggio: G major arpeggio from G2 to B4 (both channels: microphone).

4.5

52

Adult male arpeggio: G major arpeggio from G2 to B4 (right: microphone; left: electrolaryngograph*).

4.5

53

Adult male singing: Four-part multi-tracked male voice barbershop (TTBB) snippet (stereophonic presentation of microphone outputs).

4.5

54

Adult male singing: Four-part multi-tracked male voice barbershop (TTBB) snippet (stereophonic presentation of electrolaryngograph outputs).

4.5

55

Adult male singing: Four-part multi-tracked male voice barbershop (TTBB) snippet (stereophonic presentation of the upper part from the 1^st tenor part accompanied by the electrolaryngograph outputs of the three other parts).

4.5

56

Girl (9years old) singing: Hymn snippet (both channels: microphone).

4.5

57

Girl (9years old) singing: Hymn snippet (right: microphone; left: electrolaryngograph*).

4.5

58

Boy (12years old) speech: Read passage (both channels: microphone).

4.5

59

Boy (12years old) speech: Read passage (right: microphone; left: electrolaryngograph*).

4.5

60

Boy (12years old) singing: Hymn snippet (both channels: microphone).

4.5

61

Boy (12years old) singing: Hymn snippet (right: microphone; left: electrolaryngograph*).

4.5

62

Timbre demonstration material: Four notes are provided—one each from a violin, flute, bassoon and oboe. The notes have been pitch shifted to G4, amplitude ramped at the start and finish, and the steady-state portions are equalized in level. Any difference that is heard between any of these sounds results from a change in timbre, since their pitch, loudness and durations are the same (see the definition of timbre given in Section 5.1).

5.1

63

Helmholtz timbre rules: A series of sounds to illustrate each of the four timbre “rules” described in Section 5.3.2: (A) sine wave at 200 Hz (rule 1—simple tones); (B) harmonics at 200, 400, 600, 800, and 1000 Hz (rule 2—musical tones); (C) harmonics at 200, 600, 1000, 1400, 1800, 2200, 2400, 2600, 3000, 3400 and 3800 Hz (rule 3—uneven partials); (D) harmonics 1 to 20 at 200 (rule 4—distinct partials above the sixth or seventh).

5.3.2

64

Organ stops reinforcing all harmonics: The stops that reinforce the first nine harmonics (1f₀, 2f₀, 3f₀, 4f₀, 5f₀, 6f₀, 7f₀, 8f₀, 9f₀) are drawn one after the other whilst the note G4(392Hz) is held. The stops on this instrument are: chimney flute 8’, open flute 4’, nazard 2 2/3’, block flute 2’, tierce 1 3/5, larigot 1 1/3, septième 1 1/7’, octavin 1’ and none 8/9’. This enables the effect of each stop to be heard as it contributes to the timbre of the sound: a form of “analytic” listening. Then the note is repeated a few times and an arpeggio is played, and now the notes are usually heard as a whole: a form of “holistic” listening.

5.4

65

Organ stops reinforcing odd harmonics: The stops that reinforce the first five odd harmonics (1f₀, 3f₀, 5f₀, 7f₀, 9f₀) are drawn while the note G4(392Hz) is held. The stops on this instrument are: chimney flute 8’, nazard 2 2/3’, tierce 1 3/5, septième 1 1/7’ and none 8/9’. This enables the effect of each stop to be heard as it contributes to the timbre of the sound: a form of “analytic” listening. Then the note is repeated a few times and a short tune is played; now the timbre of the notes is usually heard as a whole: a form of “holistic” listening. Notice that the final effect is somewhat clarinet-like due to the spectrum consisting of the odd harmonic series (see Section 4.3.6 which discusses the acoustics of the clarinet).

5.4

66

Frequency proximity streaming: The score snippet from the Preludio from Partita III in E major by J.S. Bach shown in Figure 5.13 is synthesized to enable the streaming effect to be heard.

5.5.3

67

Grouping and frequency proximity streaming: The score snippet from the final movement of Tchaikovsky’s sixth symphony shown in Figure 5.14 is synthesized to enable the streaming effect to be heard as follows: (A) full orchestra; (B) 1^st violins and violas; (C) 2^nd violins and cellos.

5.5.3

68

Shepherd tone illusion: A demonstration of the Shepherd tone illusion which is based on the spectra shown in Figure 5.18.

5.5.4

69

Shepherd tone element: A demonstration of the circular nature of the contribution made to the Shepherd tone illusion by each component in the previous track. Figure 5.18 illustrates how each component is controlled.

5.5.4

70

Continuous scale pitch illusion 1: The snippet from the Fantasia in G minor (BWV 542) by J.S. Bach shown in Figure 5.19 is played using a registration with no reed stops in the manual parts. Follow the score and try to identify whether the upward seventh leaps are ambiguous in terms of which octave the note following the leap is in.

5.5.4

71

Continuous scale pitch illusion 2: The snippet from the Fantasia in G minor (BWV 542) by J.S. Bach shown in Figure 5.19 is played using a registration with reed stops in the manual parts. Follow the score and try to identify whether the upward seventh leaps are ambiguous in terms of which octave the note following the leap is in.

5.5.4

72

Continuous scale pitch faked: The snippet from the Fantasia in G minor (BWV 542) by J.S. Bach shown in Figure 5.19 is played using registration 1 (no reed stops) for the manual parts, but stop changes are made during the snippet to produce a pedal line that is continually descending using reed stops. This is achieved by using a schalmei 4’ for the first descending octave, then a trumpet 8’ for the second descending octave, an ophecleide 16’ for the third descending octave and a contra bombarde 32’ for the final descending seventh. It should be noted that these reeds have different timbres and intensities so the stop changes are clearly audible. Nevertheless, the long descending scale is well illustrated.

5.5.4

73

Virtual pitch—chorale played normally: Following the suggestion from Roederer quoted towards the end of Section 5.5.4, this demonstration uses the Chorale Prelude “Ich ruf’ zu dir, Herr Jesu Christ” from the Orgelbüchlein by J.S. Bach (BWV 639), which is listed in the Novello Edition (edited by Ivor Atkins and revised by Walter Emery) as chorale number 41. Chorale number 40, which is suggested by Roederer, is, according to the Novello Edition: “Es ist das Heil uns kommen her” (BWV 638), which has no solo chorale melody line and thus is not suitable for this demonstration. In this demonstration, a snippet from the chorale is performed using the stops that reinforce the first nine harmonics (chimney flute 8’, open flute 4’, nazard 2 2/3’, block flute 2’, tierce 1 3/5, larigot 1 1/3, septième 1 1/7’ octavin 1’, and none 8/9’) for the melody (a registration that would probably not be used in a performance, but one that enhances this demonstration).

5.5.4 & 3.2.2

74

Virtual pitch organ chorale: In this demonstration, the snippet from the Chorale Prelude used in Track 73 starts using the same stops that reinforce the first nine harmonics for the melody, but the stops are pushed in the following order: chimney flute 8’, open flute 4’, nazard 2 2/3’, block flute 2’, tierce 1 3/5, larigot 1 1/3, septième 1 1/7’ and octavin 1’ until only the none 8/9’ (reinforcing the ninth harmonic) remains. Then the accompaniment is removed and later brought back in. The tune is still perceivable when the stops reinforcing the low harmonics are removed, even when only the one harmonic (the ninth) remains, and it is a mutation (not a whole number of octaves away from the fundamental). When the accompaniment is removed, the pitch of the melody is somewhat ambiguous.

5.5.4 & 3.2.2

75

Short impulse response: This is the impulse response of a small church provided courtesy of Dr Damian Murphy to enable reverberation convolution for a short T₆₀.

6.1.4

76

Medium impulse response: This is the impulse response of a medium sized space provided courtesy of Dr Damian Murphy to enable reverberation convolution for a medium T₆₀.

6.1.4

77

Long impulse response: This is the impulse response of a large space provided courtesy of Dr Damian Murphy to enable reverberation convolution for a long T₆₀.

6.1.4

78

Mono, stereo and surround sound: This demonstration is for headphone listening. It illustrates how sound can be placed outside the head and moved around by tracking the change from monophonic to stereophonic to surround sound listening. The authors thank the creators of this demonstration for permission to use it on this CD. It was originally produced for The Royal Society’s Summer Science Exhibition “Surrounded by Sound” in July 2001 by members of The Music Technology Research Group, Department of Electronics, University of York.

79

Tone used in the “mosquito” or “teen deterrent”: The sound used for a mosquito or teen deterrent is 7.7 a 16.8 kHz sine wave. In this demonstration, four pure tones rising in octaves to the mosquito average frequency of 16.8 kHz are presented as follows: 2.1 kHz, 4.2 kHz, 8.4 kHz and 16.8 kHz. PLEASE NOTE: many youngsters will find the 16.8 kHz tone unpleasant—be cautious with the listening level.

7.7