Psychoacoustic impact assessment of smoothed AM/FM resonance signals - - PowerPoint PPT Presentation

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psychoacoustic impact assessment of smoothed am fm
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Psychoacoustic impact assessment of smoothed AM/FM resonance signals - - PowerPoint PPT Presentation

Sep 03, 2022 113 likes •339 views

Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Psychoacoustic impact assessment of smoothed AM/FM resonance signals Antonio Goulart, Marcelo Queiroz Joseph Timoney, Victor Lazzarini Computer

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions

Psychoacoustic impact assessment of smoothed AM/FM resonance signals

Antonio Goulart, Marcelo Queiroz Joseph Timoney, Victor Lazzarini

Computer Music Research Group - IME/USP - Brazil Sound and Digital Music Technology Group - NUIM - Ireland antonio.goulart@usp.br

SMC - 2015/07/31

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Resonance

tendency of a system to vibrate sympathetically at a particular frequency in response to energy induced at that frequency. FOF, VOSIM, ModFM, Phase distortion Analysis/resynthesis

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions TB-303

Resonance Env Mod Decay Label 60% max min A 60% max 60% B max 75% 25% C max 75% 75% D

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Waveform D 4 / 21

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions

x(t) = a(t) cos (θ(t)) ˙ θ(t) = f (t), instantaneous frequency => fits locally a(t), instantaneous amplitude various techniques Hilbert Transform ˆ x(t) = x(t) ∗ 1 πt 90◦ phase shift => analytic signal z(t) = x(t) + jˆ x(t) = |z(t)|ejθ(t) resynthesis y(t) = ˆ a(t) cos t

−∞

ˆ f (τ)dτ

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Decomposition - Waveform D - AM portion 6 / 21

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Decomposition - Waveform D - FM portion 7 / 21

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions

Boxcar window Hanning window 20 and 100 samples long window w(t) y(t) = (ˆ a ∗ w)(t) cos t

−∞

(ˆ f ∗ w)(τ)dτ

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Comparison - AM portion - Smoothing with Boxcar 20 9 / 21

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Comparison - FM portion - Smoothing with Boxcar 20 10 / 21

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Brightness

center of gravity of the spectrum related to the most prominent portion of a spectrum (specially with resonant sounds) usually the metric that presents larger variations Br =

N

  • k=1

kak

N

  • k=1

ak

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Tristimulus

introduced as a timbre equivalent to the color attributes in vision Tr1 = a1

N

  • k=1

ak Tr2 = (a2 + a3 + a4)

N

  • k=1

ak Tr3 =

N

  • k=5

ak

N

  • k=1

ak related to the warmth (3.5)

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Tristimulus

Tr1 + Tr2 + Tr3 = 1 close to origin => strong fundamental close to right corner => strong high partials close to up corner => strong mid-range partials

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Irregularity

jaggedness, ripples Ir =

N

  • k=1

(ak − ak+1)2

N

  • k=1

a2

k

, aN+1 = 0 square, clarinet => max irregularity => hollow sound impulse train => zero irregularity => buzz

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Brightness

Waveform A and C - AM/FM smoothing

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Brightness

Waveform A - AM-only and FM-only smoothing

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Tristimulus

Waveform A and C - AM/FM smoothing

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Tristimulus

Waveform A - AM-only and FM-only smoothing

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Irregularity

Waveform A and C - AM/FM smoothing

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions Irregularity

Waveform A - AM-only and FM-only smoothing

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Introduction AM/FM analysis Smoothing/Resynthesis Psychoacoustic metrics Results Conclusions

brightness/tristimulus point of view, not effective to smooth signals with strong resonance (although it certainly changes the sound) tristimulus more affected by smoothing the FM component irregularity more affected by smoothing the AM component more irregular input => more similar perceptual outcome interesting variations when processing modest and mild resonances longer smoothers => less artifacts Hanning smoothers => less artifacts suite of AM/FM effects Thanks a lot! antonio.goulart@usp.br

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