Barwa dźwięku i jej podcechy. II rok reżyserii dźwięku AM_3_2017

Transcription

1 Barwa dźwięku i jej podcechy II rok reżyserii dźwięku AM_3_2017

2 Plan wykładu Podcechy barwy dźwięku Ostrość Chropowatość Siła fluktuacji Tonalność Przykłady wtyczek audio Mag, mcdrum, mc FM, mcsnare, pspmixsat, RLH Subiektywna ocena 17 skrzypiec

3 Sharpness: Weighted first moment of distribution of critical band rates of specific loudness, proportion of high-frequency spectral components to low-frequency ones Roughness/: Fluctuation strength: Time structure of the sound signal, modulation factor and level difference determine roughness amplitudeand frequency modulation Tonality: Share of tonal, narrow-band components of a sound signal, depending on frequency, level difference and bandwidth

4 Ostrość 1 acum 1kHz, 60dB, wąskopasmowy szum, 1 acum Środek ciężkości masy

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6 Ostrość Przykład dźwiękowy wąskopasmowy szum o częstotliwości środkowej f=1 khz szum jednakowo pobudzający wysoko pasmowy szum z częstotliwością odcięcia f=3 khz

7 white noise Sharpness: Comparison von Bismark Aures of Bismark / Aures white noise and amplification of 8 khz von Bismark Aures

8 Siła fluktuacji Przykład dźwiękowy amplitudowo modulowany szerokopasmowy szum amplitudowo modulowane tony częstotliwościowo modulowane tony z częstotliwościami modulacji:1 Hz, 4 Hz,16 Hz Maksimum siły fluktuacji dla 4 Hz

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10 Przykład dźwiękowy Chropowatość ton o f=1 khz modulowany amplitudowo z częstotliwością 70 Hz zmieniać się będzie stopień modulacji : 1.0, 0.7, 0.4, 0.25, 0.125, 0.1, 0. Trzy różne dźwięki są prezentowane amplitudowo modulowany szerokopasmowy szum, amplitudowo modulowane tony, częstotliwościowo modulowane tony (+-700) z różnymi częstotliwościami modulacji: 20 Hz, 70 Hz i 200 Hz

11 Chropowatość

12 74,2 db 75,1 db 74,7 db Same A-level, Same Third Octave Spectrum

13 Critical band

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26 Marta -skrzypce

27 Expert and Non-expert Judgments of Musical Instruments: Subjective Evaluation vs Acoustical Characteristics of Musical Sound Anna Preis, Marta Chudzicka Institute of Acoustics, Adam Mickiewicz University, Poznan, Poland

28 Objectives of the study Comparison of the subjective rankings of instruments obtained for musicians and non-musicians Search for an acoustic criterium corresponding to the subjective ranking of the instruments

29 Method The experienced, professional violinist played J. S. Bach's "Partita d-moll" on 17 instruments It was a mono recording with a Neuman microphone, type U-87, and DAT Professional PCM 2600 Only the 15s excerpt of this performance was subject to acoustical analysis and to subjective assessment performed by musicians and nonmusicians subjects

30 Psychoacoustic Experiments Experiment I - sounds from 17 instruments were presented in 136 pairs. Each pair was constructed in the following way: 15s - first instrument, 0.5s pause, 15s - second instrument, 4s pause. Experiment II - sounds of 8 instruments investigated in the Experiment I were selected. These were sounds judged as very good (4 instruments) and as not so good (4 instruments). They were artificially equalized in loudness and assessed.

31 Apparatus Both experiments were controlled by the PC computer Subjects were listening to the sounds diotically through the headphones TONSIL type 5D-524 Sounds were presented randomly from the playlists created in Sound Forge 4.5

32 Subjects Experiment I subjects participated: 48 musicians and 52 non-musicians with normal-hearing They were between 20 and 50. Experiment II - 5 subjects participated: 2 musicians and 3 non-musicians, from 20 to 23.

33 Procedure You will listen to the same piece of music played on two instruments. Please mark which of the two instruments presented in a pair you would choose if you had a choice The order of the stimuli in pair was randomized The subject listened to the first stimulus, then, after a 500ms pause, to the second stimulus, and next, the subject had 4s to mark her/his judgment in a special form

34 Procedure cont. Experiment I - each of the 100 subjects made 136 preference judgments, and each instrument occurred 16 times. Each subject judged each pair of instruments only once Experiment II - each of 5 subjects made 28 preference judgments and each instrument occurred 7 times. The number of subjects was reduced but each subject judged 28 pairs of sounds in 5 repetitions

35 Results It was calculated how many times each instrument was chosen by each subject Calculated numbers were added for all subjects and divided by the number of subjects Thus, the averaged subjects choice of the preferred instrument was calculated

36 Subjects' choices of preferred instrument [%] musicians non-musicians Number of the instrument

37 A1, A4

38 A16, A9

39 A16, A5

40 Experiment I - results The most frequently chosen was instrument No. 1 The least chosen was instrument No. 16 The differences in the results of musicians and non-musicians are not statistically significant

41 Musicians' choices of preferred instrument [%] R 2 = 0, Non-musicians' choices of preferred instrument [%]

42 Experiment I - results cont. Three groups of instruments were identified: 1, 3, 4, 5, 6 were judged as very good 7, 8, 10, 17 were judged as good, 9, 11, 12, 13, 14, 15, 16, 19 were judged as not so good

43 Experiment I results cont. The subjective ranking obtained in Experiment I highly correlated with the values of total loudness (R 2 =0.84) It indicates that the preference choices were primarily influenced by loudness Experiment II - 4 loudest and 4 softest violins were chosen. The total loudness of these 8 instruments (Table 1, column 5) was artificially equalized.

44 Violin Jansson,Niewczyk Present study N Ex.I [sone] N Ex.II [sone] 1 Good Very good Good Very good Very good Very good Good Very good Not so good Very good Not so good Good Not so good Good Good Not so good Good Good Not so good Not so good Very good Not so good Not so good Not so good Good Not so good Not so good Not so good Not so good Not so good Good Good Not so good Not so good

45 Experiment II results cont. The subjective ranking obtained in Experiment II is almost identical with the results obtained in Experiment I, (with the exception of the instrument No.14) However, the differences between the instruments 5, 6 and 9, 12, 14, 16 were smaller in Experiment II than in Experiment I

46 Subjects' choices of preferred instrument [%] Musicians I Non-musicians I Non-musicians II Number of the instrument

47 Experiment II results cont. The time patterns of the instruments belonging to the same group are strongly similar. This is true for the pairs 1-4, In the case of pair 5-6 they are identical The time patterns of the instruments belonging to the different groups are shifted both in time and in the amplitude (total loudness versus time) eg. pair 5-16

48 Total loudness [sone] No. 1 No Time [s]

49 Total loudness [sone] No. 5 No Time [s]

50 Conclusions The preference judgments of the violins obtained for musicians do not differ from the preference judgments obtained for nonmusicians It is easy, even for a layman to make a preference judgment of the instruments presented in a pair. Judgment of a single instrument demands experience. This explains why judgments of musicians and non-musicians did not differ significantly. In the original recordings of the different violins the total loudness correlates best with the subjective judgments of the instrument

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53 Subjects' choices of preferred instrument [%] Subjects' choices of preferred instrument [%] musicians non-musicians Number of the instrument Musicians I Non-musicians I Non-musicians II Number of the instrument