Andri Bezzola, PhD

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Audio Product Development at Samsung Audio LabBetter and Faster With Simulations

Overview

• Introduction

• Nonlinear Distortion in a Woofer

• Optimization of SAMSUNG LED WALL HF Waveguide

• Conclusion & Outlook

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3COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Samsung ElectronicsFast Facts 1969 Vision2020 320,671

Year Founded

Inspire the World,Create the Future

# of Employees(Dec 2017)

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD 4

Global R&D Network

OF ENTIRE WORKFORCE

15

40.7 M DAILY

INVESTMENT (USD)

14.9 B TOTAL

INVESTMENT (USD)

Issued Patents

5

0 5000 10000

2014

2015

2016

2017

Issued US Utility Patents By Year

Toshiba

Qualcomm

Microsoft

Sony

Canon

IBM

Samsung

EuropeUS

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Top 10 Patentees in 20172016: 3rd

2015: 2nd

2014: 1st

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Samsung Audio LabValencia, CA

2013 First Hire

1700 Lab Area in m2

2 Anechoic Chambers

3 Listening Rooms

2 Transducer Test Rooms

7

21 FTEs | 300+ Years of Audio Engineering and Research Experience4 PhD | 6 MSc | 8 Active Musicians

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

8COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

• Acoustic simulations for tweeter phase plug

• Acoustic simulations for woofer lens

• Static Electromagnetic simulations for woofer driver

Samsung Audio Lab Products2015 R-Series Wireless Speaker

9COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

• Acoustic simulations for height channel

• Project launch to CES prototype: 6 weeks

• Project launch to mass production: 5 months

• First Samsung soundbar to ever achieve 5 star rating from Home Cinema Choice

Samsung Audio Lab Products 2016 First Dolby ATMOS Soundbar K950

Loudspeakers are Multiphysics, Multiscale, and Nonlinear

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AC/DC Nonlinear magnets Saturation in steel

Structural Mechanics Anisotropic materials Large deformations Frequency dependent damping

Acoustics f = 20 Hz to 20 kHz λ = 17 m to 17 mm Infinite domains and far-field

measurements Losses in narrow regions

Heat Transfer Temperature from -20°C to 200°C

Fluid Dynamics Turbulent bidirectional air flow

through ports and vents

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

11COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Nonlinear DistortionSounds Bad

LinearWoofer

Non-Linear Woofer

Track 1

Track 2

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Nonlinear DistortionAnti-Distortion

LinearWoofer

Non-Linear Woofer

Corrected

Track 1

Track 2

𝒈(𝑿, 𝒖)

𝒇(𝑿)

1/s C𝑢 [𝑉] 𝑥 [𝑚𝑚]𝑋�̇�+

𝑋 = [𝑥, �̇�, 𝑖] 𝑔 𝑋, 𝑢 = [0, 0, 𝑢 𝐿 𝑥⁄ ]�̇� = 𝑔 𝑋, 𝑢 + 𝑓 𝑋 𝐶 = 1, 0, 0𝑥 = 𝐶 𝑋

𝑓 𝑋 = 1

𝑀

�̇�

−𝐾 𝑥 𝑥 − 𝑅 �̇� + 𝐵𝐿 𝑥 𝑖 +𝑖

2 𝑑𝐿 𝑥

𝑑𝑥

1

𝐿 (𝑥)−𝐵𝐿 𝑥 �̇� − 𝑅 𝑖 −

𝑑𝐿 𝑥

𝑑𝑥�̇� 𝑖

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

13COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of Kms(x)Geometry Import

14COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of Kms(x)Selection Definition

15COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of Kms(x)Material Definition

16COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of Kms(x)Mesh Setup

17COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of Kms(x)Solve

18COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of Kms(x)Outstroke and Instroke

19COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of Kms(x)Results

20COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of BL(x)Geometry Import

21COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of BL(x)Selection Definition

22COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of BL(x)Material Choice

23COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of BL(x)Mesh

24COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of BL(x)B-Field and BL Curve

25COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

COMSOL Apps for Calculation of BL(x)B-Field and BL Curve

InductanceCoupling of B-Field, Current, and Velocity

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• Self Inductance of a Wire Loop

𝑉 𝑡 = 𝐿𝑑𝑖 𝑡

dt= −

𝑑Φ

𝑑𝑡• Magnetic Flux

Φ = 𝐵 𝑑𝑎

= 𝜇 𝜇 𝐻 𝑑𝑎

• Ampère’s Law

𝛻 × 𝐵 = 𝜇 𝐽

• Current in Voice Coil

𝑖 = 𝑉 − 𝐵𝐿 𝑣 −

𝑑Φ𝑑𝑡

𝑅

• Magnetic Force on Voice Coil

𝐹 = 𝐵𝐿 𝑖

Le: Inductance

i: Current in the voice coil wire

Φ: Magnetic flux through voice coil

B: Magnetic flux density vector field

μ : Magnetic permeability in vacuum

μ : Relative permeability (saturation dependent)

H: Magnetic strength

BL: Radial component of magnetic B-field integrated over the length of the voice coil wire

J: Total current density per square meter

Vo: Applied voltage from amplifier

v: Voice coil velocity

Re: Resistance of voice coil wire

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

27

Non-Linear Distortion in a WooferCoupling PDE and ODE

Lumped Model (ODE)

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

FEM (PDE)

Moving Mesh for Large Deformations

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Prescribed Deformation x(t) from ODE

Free DeformationLaplace smoothing ensures even distribution

Static MeshEverywhere else

Continuity ConditionBetween moving mesh and static mesh

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

A Better Approach in COMSOL®:Moving Physics

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u: Voice coil position from ODEN0: Number of turnsh0_VC : Height of voice coilIcoil: Current in voice coil

𝑖 =𝑉 − 𝐵𝐿 𝑣 − 𝑉

𝑅

𝑉 = −𝑑𝜙

𝑑𝑡=

2 𝜋𝑅 𝑁

ℎ

𝑑𝐴

𝑑𝑡 𝑝𝑤1 𝑧 − 𝑢 𝑑𝑧

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhDCOMSOL is a registered trademark of COMSOL AB.

Dynamic Simulation Transducer A

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Dynamic Simulation Transducer B

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Quantifiably Better Drivers Through Simulation

32

Driver A Driver B

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

BL(x(t))Static BL(x)

BL(x(t))Static BL(x)

33

Optimizing a WaveguideSAMSUNG LED WALL

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

34COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Optimizing a WaveguideSpecific Constraints

• Very wide sweet spot

• Control sound horizontally and vertically

• Limited space available

• Must be able to play at high volume

Traditional Cinema Loudspeaker SystemsWaveguides and Compression Drivers

35COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Best Frequency Response at Sweet Spot

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Measured

Target

Equalized

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Equalization (EQ)

Optimal Frequency Response at Many Points

37

Normalized to Sweet Spot

Φ [∘]

Φ

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Optimizing a WaveguideParametrization

• 3 Bezier Cross Sections

• Waveguide depth (fixed)

• Inner Diameter (fixed)

• Outer Diameter (fixed, except 45°)

• Tangency to driver exit and baffle

• Strength of tangency given by 𝐿 , 𝐿

38

Throataxis

1+(3x2) =

7 Control Variables

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Optimizing a WaveguideTarget

• Fixed 1 dB down at 20° and

10 kHz

• Fixed 6 dB down at 60° and

10 kHz

• Straight lines with variable

values at 1 kHz

• 2 additional control variables

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Straight Lines in Off-Axis Plot

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Optimizing a WaveguideCOMSOL® Implementation

• LiveLink™ for SOLIDWORKS®

• Pressure Acoustics, Frequency Domain (acpr)

– Semi-infinite domain (PML)

– Speaker mounted to infinite wall (3 x symmetry)

– Constant acceleration at throat

• Optimization

– Parameter Optimization

– Nelder-Mead

• Mesh

– Free tetrahedral and swept mesh (in PML)

• Study

– Frequency Domain, 3rd octave frequencies

40COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhDCOMSOL and LiveLink are trademarks or registered trademarks of COMSOL AB. SOLIDWORKS is a registered trademark of Dassault Systèmes SolidWorks Corp.

Optimizing a WaveguideOptimization

41COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Optimizing a Waveguide3D Printed Prototype

• Measured in 2π-configuration

• Mounted flush to wall of 2πanechoic chamber

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Optimizing a WaveguideOff-Axis Results

43

SimulatedMeasured

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

SimulatedMeasured

Horizontal Off-Axis Response Vertical Off-Axis Response

Optimizing a WaveguideResults

44

Directivity Plots: Horizontal Plane

Simulated Measured

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Optimizing a WaveguideResults

45

Directivity Plots: Vertical Plane

Simulated Measured

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Other Fun Simulations

46

Topology Optimization for Acoustics

Straight Port Flared Port

Fluid-Structure & Fluid-Acoustic Interaction

Bezzola, A., “Numerical Optimization Strategies for Acoustic Elements in Loudspeaker Design,” in 145th Audio Eng. Soc. Int. Conv. 2018, p.10046, New York City, 2018

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

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Conclusion & Outlook

COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

• Loudspeakers are inherently multiphysics

• Simulations with COMSOL® are integral to

product development at Samsung Audio Lab

• Simulation Apps accelerate product

development

• Optimization reduces development time

• Simulations need empirical backup,

simulation engineers need a team!

• Do not hesitate to consult COMSOL support

COMSOL is a registered trademark of COMSOL AB.

Thank you!

SAMSUNG PROPRIETARY/CONFIDENTIAL – INTERNAL USE ONLYCopyright © 2014 Samsung Research America. All rights reserved.

Thank you!Thank you!

Copyright © 2017 Samsung Research America All rights reserved. Samsung Research America and the Samsung Logo are trademarks or registered trademarks of Samsung Group or its affiliates in the U.S. and other countries. Other names may be trademarks of their respective owners.

This document is provided for informational purposes only and is not intended as advertising. All warranties relating to the information in this document, either express or implied, are disclaimed to the maximum extent allowed by law. The information in this document is subject to change without notice.

Andri Bezzola, PhDandri.b@samsung.comwww.linkedin.com/in/andribezzola

48COMSOL Conference | 2018-10-23 | Lausanne, Switzerland | Andri Bezzola, PhD

Special thanks to:

• Alyona Friedel and Zoran Vidakovic

• COMSOL Support Team

• COMSOL Team in Los Angeles

• Samsung Research America

• Samsung Audio Lab Team