parallel dsp for efficient piano synthesis

College of Engineering Pune (COEP) Forerunners in Technical Education

A seminar onPARALLEL DIGITAL SIGNAL PROCESSING FOR

EFFICIENT PIANO SYNTHESISPresented by

Mahesh Pawar(MIS-121697010)


INTRODUCTION

1. Digital Piano 2. Computational techniques used in piano3. Physics based algorithm4. Parallel signal processing5. Virtual reality6. To drive musical instruments7. Haptics and spatial audio


BACKGROUND

1.Traditional and Physics based synthesis 2.Realistic performance can be observed3.Sympathetic Resonance4.Vibrotactile feedback in virtual pianos

Vibrotactile Feedback


NECESSITY OF PARALLEL DSP

1.Large computational requirement2.Higher Throughput3.Important for keyboard which are small like portable devices


ARCHITECTURE OF PIANO SYNTHESIS

1.Signal Processing blocks corresponding to mech. elements - Hammer is for exciter - String is for resonator - Instrument body is for resonator2. String partial differential equation3.Discretization technique used in Numerical solution4.Previous Methods used for Solution of PDE of string - Finite difference - Digital waveguide 5.New method : Variation of modal Synthesis


(Continued……….)

6.Base of Algorithm: Decomposition of the string displacement

Where , y(t) = amplitude of the partial

7. This results in ordinary 2nd order DE for each modes

N

nn L

xntytxy1

)sin()(),(


NUMERICAL COMPUTATION OF STRING BLOCKS

2,2

1,1

1,1

,mod

1,,mod,

1

)()(

)()()(

zazazb

H

WzHWzH

zFzHzF

kk

kke

N

kkoutkekinstring

hstringstring

Where, Fstring (z) : is the transversal force at the bridge Fh (z) is the force coming from the hammer Hmode,k(z) are the transfer functions of the normal modes


BLOCKS OF ACOUSTIC PIANO MODEL•Secondary Resonators - Needed for simulating the complex beating envelopes found in piano partials - They are employed for the simulation of the sympathetic resonance effect•duplex resonators model - A portion of the strings above their speaking length - Synchronization Mechanism is required

Synthesis Architecture of the acoustic piano model


SOUNDBOARD FILTERING

-Soundboard Radiation Module-First Version of Piano : Block based convolution-Algorithm capable of computing 4 responses at the same time-It is based on parallel second-order filter approximation -Buffer size is kept low (64 samples)-50x faster compared to FFT based convolution


PARALLEL IMPLEMENTATION

- Maximum number of resonators : 1. C674x : 5200 2. Cortex – A7 : 3920 3. x86-i5 : 17300-Modelling of soundboard would require nearly 3 GFLOPS-Parallel computation of N oscillators is obtained by resorting to explicit SIMD instruction, SSE2 or NEON for x86 and ARM processors.


C67x basics1.Can implement complex linear or nonlinear algorithms.3. Can modify easily by changing software.4. Reduced parts count makes fabrication easier5. High reliability6. Features : - Operating at 225 MHz - AIC23 stereo codec - 16 MB RAM, 512 MB non-volatile memory - Software board configurations - Configurable boot options - Expansion Connections - JTAG emulation


BLOCK DIAGRAM OF PARALLEL COMPUTING SYSTEM


CHALLENGES

1.Parallel solutions are harder to implement2.suffers from communication and coordination overhead3.Upper bound on Speed up4.Complexity5.Portability6.Resource requirement7.Scalability8.Parallel slowdown


CONCLUSION1. Parallel DSP can reduce the power consumption of a system by reducing the supply voltage.2. This Model presents technical aspects of modern computational acoustics.3. Useful for both digital piano and virtual musical instrument.4. This model allows for large computational savings.5. Resonators emulate both Sympathetic resonance and envelope effects.


REFERENCES

[1] Federico Fontana, Hanna J¨arvel¨ainen, Stefano Papetti, Federico Avanzini, Francesco Zanini, and Valerio Zanini, “Perception of interactive vibrotactile cues on the acoustic grand and upright piano,” in Proc.Of Joint SMC and ICMC 2014 Conference. National and Kapdistrian University of Athens, Greece, 2014.

[2] Yuri De Pra, Fausto Spoto, Federico Fontana, and Linmi Tao, “Infrared vs. ultrasonic finger detection on a virtual piano keyboard,”in Proc.of Joint SMC and ICMC 2014 Conference.National and Kapodistrian University of Athens,Greece, 2014.

[3] Stefano Zambon, Leonardo Gabrielli, and Balazs Bank, “Expressive physical modeling of keyboard instruments: From theory to implementation,” in Audio Engineering Society Convention 134. Audio Engineering Society, 2013.

[4] S. Zambon, E. Giordani, B. Bank, and F. Fontana, “A system to reproduce the sound of a stringed instrument,” Deposited PCT international patent, March 2013.


Thank You


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Fig. Acoustic Piano Model<<


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Fig. : Architecture of c6713


Fig. : Block diagram of c6713 kit


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