AFMG - Department of Radio Engineering FEE CTU Pragueradio.feld.cvut.cz/AES/ahnert.pdf · W. Ahnert...
Transcript of AFMG - Department of Radio Engineering FEE CTU Pragueradio.feld.cvut.cz/AES/ahnert.pdf · W. Ahnert...
AFMG AHNERT FEISTEL MEDIA GROUP
Brno 19.10.2011
Acoustic Simulation and Sound System Design
Wolfgang Ahnert
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Overview
• Short review of development of acoustic simulation
• Software EASE
• Speaker, wall and other data
• Extension to lower frequencies
• Intelligibility calculation
• Measurement tools
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Development in Designing
Paths to sure planing: • Roman/ Greek time/ middle age: knowledge based on experiance and
first trial and error reports, i.e. rom. architect Vitruv • since 18. century: investigations, i.e. Chladni or at 1875 Lord Rayleigh,
Prof. Helmholtz • since 1900: roomacoustic basics, Prof. Sabine • by 1935: measurement in models and „Auralisation“ in physical
models, Prof. Spandöck München, Prof. Reichardt Dresden • since 1965: computer model investigations, Prof. Krokstad Trondheim,
afterwards a lot of similar works • since 1995: Auralisation by means of computer models is available
generally
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1988, CATT-Acoustic, by Dalenbeck/Sweden
Version 1, now version 8.6
1991, ODEON, by Naylor&Rindel/Denmark
Version 1, now version 10.0
1994, RAMSETE, Faria/Italy,
Version 1, now version 2.xx
1998/2001, CAESAR, 1998 by Vorländer/Schmitz/Aachen/Germany
Version 0.12, 2001 vers. 0.20
2001, EASE, by Ahnert/Feistel/Berlin/Germany
Version 4.0, Autumn 2009 EASE 4.3
Room Acoustics Programs
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EASE 4.3. ….5.0
Modules for Editing and Calculation
SpeakerLab
MaterialLab MicrophoneLab
InterfaceLab
Block diagram
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SpeakerLab
GLL for different speaker types Point sources Arrays Cluster
GLL for natural sources Human sources Music instruments
Import and export routines
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1000 Hz
Point Source presentation
Magnitude and Phase balloon
wrapped
unwrapped
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5000 Hz
Point Source presentation
Magnitude and Phase balloon unwrapped
wrapped
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Loudspeaker data
Import routine for Wav-files
Identification of the rotation point in data sheets:
Standard AES56-2008
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Loudspeaker data base - Cluster
A Cluster calculation routine is a far field approach
Using the measured or simulated balloon data of a single device you calculate the cluster by means of:
power summation
complex integration
all with different angle and frequency band resolution
View cluster shows the components of the cluster
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Different cluster calculation
Already in EASE 3.0, Only run time phase consideration
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Arrays with In-line Arrangement of Radiators
where n = number of individual loudspeakers d = spacing of the individual loudspeakers = radiation angle = wave length of sound l = (n-1) d = length of the loudspeaker line
Each of the individual loudspeakers radiates the sound spherically and the sound waves get favorably superposed in the far field, whereas the effect of the individual loudspeaker prevails in the near field. For the far field the equation above was given already by STENZEL 1927, 1939 and OLSON 1947 for the angular directivity ratio , the so-called polars.
STENZEL, H.: Über die Richtwirkung von Schallstrahlern, Elektrische Nachrichten-Technik, Band 4 (1927), Seite 239 STENZEL, H.: Leitfaden zur Berechnung von Schallvorgängen, Verlag von Julius Springer, Berlin 1939 OLSON, H.F.: Elements of Acoustical Engineering, D. van Nostrand Company, 2nd edition, New York 1947
Classical columns (Loudspeaker Line, Sound Column)
sinsin
sinsin
dn
dn
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Speaker type Cluster
already in EASE 3.0
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Cluster calculations
1 speaker
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Cluster calculations
2 speaker
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Cluster calculations
3 speaker
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Cluster calculations
4 speaker
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Cluster calculations
5 speaker
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Cluster calculations
6 speaker
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Arrays with In-line Arrangement of Radiators Many manufactures like L-Acoustics, JBL, Electro-Voice, Nexo, Adamson or Meyer Sound produce line arrays, here as an example Vertec/JBL:
In EASE4.0 it was no longer possible to represent these systems by means of simple point sources with directional irradiation. Thus an algorithm has to be employed that is capable of calculating the attainable sound level according to the array structure as well as the distances and frequencies involved. To this effect there are special product-specific DLLs available that are called up by the respective main program.
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Speaker type Line Array
Renkus-Heinz AimWare
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Speaker type Line Array
EASE Focus
Software
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Iconyx 8
Electronically steerable column loudspeaker by Renkus-Heinz
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DURAN Audio Intellivox 2c
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Arrays with In-line Arrangement of Radiators Digitally controlled line arrays
A way of reducing the frequency dependence of the directional characteristics and directivity of sound lines (the figures below illustrate such an unwanted directional effect in three-dimensional representation) consists of supplying the sound signal, with different phases and levels, to the individual loudspeakers in an array.
1000Hz 2000Hz 4000Hz
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DURAN Audio Intellivox 2c
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DURAN Audio Intellivox 2c
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Line Array Simulation
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Line Array Simulation: Direct SPL on faces
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New Data Format
Until now: Point Sources, Cluster Dynamic Loudspeaker Libraries DLL and now: Generic Loudspeaker Library GLL
What„s that?
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Generic Loudspeaker Library GLL
Why GLL – Another loudspeaker data format? History:
EASE 1.x : 15° and 1/1 Octave half sphere data, magnitude only EASE 2.x : 10° and 1/1 Octave half sphere data, magnitude only EASE 3.x : 5° and 1/3 Octave full sphere data, magnitude only EASE 4.0/4.1: 5° and 1/3 Octave full sphere data,
complex data + DLL modeling capabilities
Problem: Fixed data tables, no user configurability Many constraints due to data reduction or interpolation to fit
tabular format Data resolution not adapted to modeling goals
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GLL – Motivation
Typical Problems with Tabular Data: Active or switchable passive multi-way loudspeakers Stack of 2 two-way loudspeakers Column loudspeakers, tapered or digitally steered Touring line arrays Cluster systems
Modeling Requirements: Data resolution > 1/3rd Octave Add coherence information, phase Mechanical configurability (rigging) Electronical configurability (filters) Better integration with manufacturer
control software
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Create a GLL What is needed to create a GLL?
Data for individually controlled transducers must be measured individually
For each point source of the model: IR/FR balloon data in sufficient angular resolution (EASERA, TEF, MLSSA, MF, CLIO, LMS, etc.)
Sensitivity is calculated automatically from calibrated on-axis response
Maximum voltage over the rated bandwidth
Impedance data (optional)
=> Stored as a GSS file
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Create a GLL Generic Sound Source (GSS) Data:
Data is stored in its native format using high-resolution storage and compression algorithms Rather than enforcing data provision in a fixed format, data points required for prediction are interpolated from available data points
– Preferably complex data, error ranges as determined by rotation point and critical frequency
– New definition of power handling
– Flexible import functions
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Create a GLL
What is needed to create a GLL?
Combine sources in a box:
3D location of all transducers / source groups
Define input matrix (external inputs -> acoustic outputs)
Available filters (matrix nodes)
Case drawing
GLL Box Type
Sources
Filter Groups
Input Configurations
HF
LF LF XO
HF XO
Active System
HF
LF LF XO
HF XO
Passive System
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Design and Analysis Tool Design Tool EASE SpeakerLab:
Driver placement and orientation
Crossover design
Filter development for steered columns
Validation of mechanical design
=> Directivity Prediction
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Design and Analysis Tool Analysis Tool EASE SpeakerLab :
For measured data and predicted data
Validation and evaluation over angle and frequency
Variety of graphs: Frequency Response, Balloons, Polars , Beamwidth, Hor./Ver. Mapping, Directivity, etc.
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MicrophoneLab
• GLL for different microphone types • Omnidirectional microphones • Directed Microphones • Arrays
• GLL for natural receivers • Human ears • Dummy head • HRTF database
• Import and export routines
38 www.AFMG.eu
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Microphone database
First approach to collect microphone data for EASE
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MaterialLab
• Interface to SoundFlow • Angle-dependent absorption and scattering values • Interface to Reflex • Data Storage in compiled form • Import of text and picture files • Contact information to web sites • Providing import routines for manufactures to
create material data • Import routine for *.mat files
40 www.AFMG.eu
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Calculation of the Acoustic Properties of Multi-Layer Walls
Calculation: • Impedance describes the acoustic
properties:
• Z = p0/v0
• Calculation of transmission:
• t = |pN/p0|²
• Boundary conditions for back size:
• Rigid wall: Sound velocity is 0
• Air: Characteristic impedance of air
• Multi-layer structures are calculated layer by layer: (pn,vn)->(pn-1,vn-1)
• Different computational models can be applied to each layer
pN-1
vN-1
p0 p1
v0 v1
pn-1 pn
vn-1 vn
1 2 3
p0 v0
pN vN
Air
vN = 1/ZAir pN = 1
pN = 1 vN = 0
Rigid Wall
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Transmission Loss: Simulation vs. Measurement
0
10
20
30
40
50
60
70
80
100 1000 10000
Tra
nsm
issio
n L
oss /
dB
Frequency / Hz
Transmission Loss [dB]Porous Material placed between two plates
Journal of Sound and Vibration (1992) 155(1), 125-132
SoundFlow
LAURICKS et. al.
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Absorption Coefficient: Simulation vs. Measurement
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
100 1000 10000
alp
ha
Frequency / Hz
Absorption Coefficient Microperforated Panel
J. Acoust. Soc. Am. 104 (5), Nov. 1998
SoundFlow
Dah-You Maa
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Software AFMG SoundFlow
Features:
• Entry of layers and thicknesses
• Definition of „raw materials“
• Calculation of transmission, absorption, reflection
• Result output as report document or pictures
• Direct export to EASE
44 www.AFMG.eu
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Future Improvements in SoundFlow
• Improve the model for thick plates
• Add different connection types between layers
• Rigid connection (sandwich plates, laminated)
• Rigid line/point connection (studs, structural bridges)
• Viscous
• Conical holes
• Eigenfrequencies on finite sized walls
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Boundary Element Method
• Solves differential equations on the boundary of a domain
• Useful for solving scattering problems • Can be coupled to FEM to solve semi-open rooms • Advantages:
• Fast & exact for “small” problems • Can be used for open domains
• Disadvantages: • Scales in contract to FEM • Needs fundamental solution
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Calculation of Scattering by a Structured Surface using BEM
Steps: • Structured surface • Tessellation into segments • Incident plane wave • Calculation of sound
pressure at surface • Solving the system of
linear equations • Resulting sound pressure • Calculation of reflected
wave front
pin[0] pin[1] pin[n] …
pout[0] pout[1] pout[n] …
BEM M pout = pin
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Quantify scattering
Scattering Coefficient Autocorrelation diffusion coefficient
Normalized diffusion coefficient Correlation Scattering Coefficient Correlation with response of flat panel
S = 0.7
S = 0.15
S = 0
D = 0.85
D = 0.35
flat
flat
nd
ddd
1
total
spec
E
Es 1
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Calculation of Scattering Coefficient
Calculation:
• Comparison with flat panel
• Calculation of spatial distribution using BEM
• Comparison of distributions
• Calculation of correlation function
• -> scattering coefficient
2kHz 2kHz BEM BEM
2kHz
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Calculation of Diffusion Coefficient Calculation:
• BEM – Calculation of spatial distribution
• Autocorrelation
• -> diffusion coefficient
• Comparison with flat panel -> normalized diffusion coefficient
• Also smooth surfaces may yield high diffusion coefficients at low frequencies
• Normalization to suppress this edge effect
• Scattering coefficient compares with geometrical reflection only
2kHz BEM 2kHz BEM
Autocorrelation Autocorrelation
100 Hz
800 Hz
100 Hz
800 Hz
100 Hz
800 Hz
100 Hz
800 Hz
100 Hz
800 Hz
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Scattering Coefficients: Simulation vs. Measurement
Comparison:
• Measurement according to ISO 17497-1
• Simulation of „Correlation Scattering Coefficient“ according to Mommertz
• Match is quite good, esp. for use in EASE
0
0,5
1
100 1000 10000
Frequency / Hz
Measurement
AFMG Reflex
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Measurement in cooperation with RPG Diffusors Inc.
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Scattering Coefficients: Simulation vs. Measurement
Comparison:
• Measurement according to ISO 17497-1
• Simulation of „Correlation Scattering Coefficient“ according to Mommertz
• Match is quite good, esp. for use in EASE
0
0,5
1
100 1000 10000
Frequency / Hz
Measurement
AFMG Reflex
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Measurement in cooperation with RPG Diffusors Inc.
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Software AFMG Reflex
Features:
• Entry of geometry as a cross section
• Calculation of spatial response
• Calculation of coefficients
• Result output as report document or pictures
• Direct export to EASE
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Reflection at structured surface
a
a
cf
2
a
cf
2
a
cf
2
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Outlook for AFMG Reflex
• In development • Better handling of small element • Higher order base functions
• Possible extensions • Import/Export of model data • Spline elements • Adding non-rigid BCs • Extending to 2 dimensions
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InterfaceLab
Import/Export from and to AutoCad Import/Export from and to SketchUp Import/Export from and to BIM Simple routines to create Models
3D Modules Prototypes Import from other CAD programs
Laser scanning Holographic approach
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Interface in EASE 4.3
Support for DXF2000 and Sketchup formats
Import and Export
Up to Google SKP 7.0
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Modeling Techniques
Computational
Modelling
Wave-Based
Modelling
Ray-Based
Modelling
Statistical
Modelling
Difference
Methods
Element
Methods
Ray
Tracing
Mirror
Image SEA
FEM BEM
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Room acoustical computer simulation
Simulation algorithm
CAD model + material data
Objective single number quantities
Realtime convolution
EARS
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Impulse response calculations
Ray Tracing with counting balloon
Image Model method
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Image sources
P
R
S
S1
S2
S12
S21
wall 2
wall 1
ii nnnnnnnnn SSSSS ...... 21121211...
• Geometrical construction
• Audibility test
• Very expensive for high reflection orders
time
Energy
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n2
n1
n9
n8
n3
n7
n6
n4
n5
P r0
r
S
source
Ray tracing
ray source
wall reflection
detection
r/ c > tmax ?
last ray ?
end
detector
detector
source
distance law: ray density
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Hybrid models
• „Forward audibility test of image sources“
• Rays (cones, ...) hitting a receiver can be addressed to audible image sources
• Dialects: Tracing of cones, triangular beams, pyramids, ..
• Higher Order possible but some mirror images are missed
• Parameter : spatial resolution calculation time
detector
(image) source
distance law: analytically t = rIS/c, E ~ 1/rIS2
rIS
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Echogram
• Recording of counts and energy in time histograms
t
tray = rray/c
t
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Fast calculation routines
• Fast Calculation of Impulse Responses
• Sophisticated Hybrid Algorithms
• Use of scattering coefficients
• Use of diffraction effects
• Fast intern calculation routines
• Multi-Thread approaches
• Network calculation
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Intersection Algorithms Overview:
- In raytracing for a given ray vector often the next
intersecting surface (triangle) must be found
- Brute force approach, e.g. linear search through all triangles for the nearest intersection point, is very time-consuming
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Intersection Algorithms
Previous Algorithm in EASE: - Log-based Hierarchival bounding volumes (HBV)
method
- From Outdoor 3D rendering engine
- Hierarchy of multiple Spheres and Boxes
- a particular child-volume is only tested if the parent was hit
- the resulting computation scaling with the number of triangles is approximately logarithmic
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Intersection Algorithms
New Algorithm in v4.2:
- Log-based space partitioning
- Indoor-optimized
- Uniform Single-Level Grid (Each triangle associated with a grid cell is then
tested for intersection with the ray)
- Enables Vector Processing
(Given a ray specified by an origin and direction
vector, a fast grid traversal algorithm computes
the next grid cell intersected by the ray)
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Intersection Algorithms Result: Algorithm optimized for acoustic models can be up to 5 times faster (standard
Pentium 4)
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Multi-thread Mode in EASE 4.3
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Multi-thread Mode
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Node Server
Master Server
Simulations
SoftwareJob DB
Job ControllerComputation
Module
Job Controller Job Manager
SSH Deamon
Job StarterSSH Deamon
secure
connection
via the
internet
execute the
computation
module
control the
computation module
via a loopback
connection
start & control
simulation processes
via the local network
Network File System
Storage for
simulation data
and resultsjob control via
loopback
connection
LANInternet
Server Cluster
Job Management
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Server Cluster
Calculation Time Improvement
0,0
5,0
10,0
15,0
20,0
25,0
0 1 2 3 4 5 6 7 8 9
Ca
lcu
lati
on
Tim
e [h
]
Number of Nodes
Multi-Node Calculations
Railway Station
Cathedral
Stadium
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Airport model with 1952 loudspeakers
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Server Cluster Call
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Energy time curve EDT, T10,
T20, T30
C80, C50
LF, LFC
TS, Echo
AlCons, STI, RaSTI
Level etc.
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Extension to low frequencies
• Theoretical Background
• Schroeder frequency
• Modal sound field
• Transmission in modal sound field
• Simulation and Measurement
• Finite Element Method - FEM
• Boundary conditions
• Comparison of measurement and simulation results
• Optimizing absorber locations
• Summary to FEM calculation
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Schroeder Frequency
Resonances in closed volumes
Modal density ~ f²
Diffuse sound field above Schroeder Frequency
=> Marks transition between wave and geometrical acoustics
Geometrical Acoustics
Wave
Aco
ustics
V
Tfs 2000
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Modal Sound Field
Modes result from room geometry
Complex spatial resonance patterns in 3D
34 Hz
68 Hz
103 Hz
137 Hz
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Sound Transmission in Modal Field
Isolated mode creates max-min pair
Transfer function is symmetric regarding receiver / source
Mode at 40 Hz
E1 E2
E3
E4
E5
Mode at 75 Hz
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Sound Transmission in Modal Field
Damping reduces the quality (Q) of the mode
Transfer function is smoother
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Exciting undamped Modes
24,5Hz 34,5Hz
Point Source at 25Hz Point Source at 30Hz
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Exciting damped Modes
Point source in undamped room
Point source in damped room
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Listening Room
Volume 49 m³
RT ~0.15 s
Schroeder-Frequency
fs = 110 Hz
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Simulation of Modal Sound Field Modeling wave acoustics using FEM
3D volume mesh of room
Solving the Helmholtz equation with boundary conditions
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Boundary Conditions for Simulations
• Geometric acoustics
• Absorption
• Scattering
• Wave based acoustics
• impedance
p 2 v 2
p 1
v 1
1 2 3 Air Air Z0 = c Z0 = c
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Modal Distribution
82 Hz
54 Hz
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Measurement versus Simulation
Right
Left Center
Comparison:
• Good qualitative reproduction of transfer function
• Simulation results show critical frequencies
Simulation
Measurement
Simulation
Measurement
Simulation
Measurement
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Damping of Selected Modes • TF shows notch at ~90 Hz - how to smooth it?
• => Dampen corresponding mode
• Modes form between hard surfaces, pressure max on the surface
• => Replace hard surface material by absorber to suppress pressure max
• => Mode is attenuated
Measurement
Simulation
~ 90 Hz
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Damping of Selected Modes
Measurement Simulation
Without Absorber With Absorber
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Summary to FEM Calculation
• FEM modeling for low frequency range
• Determining complex boundary conditions can be difficult
• Qualitative results easily possible
• Optimize modal sound field regarding
• Loudspeaker placement
• Absorber type and placement
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Speech Intelligibility
STI according to IEC 60268-16 (2003)
• Background
• Impulse response and modulation functions
• Implementation
• Eyring/Sabine model
• Noise levels
• Signal masking
• Criticism
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Speech Intelligibility
Background:
Measurement via Modulation or IR: 14x7 MTF Values => STI
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Speech Intelligibility
Typical MTF, STI and Scale:
STI = 0.590
> 0.75 Excellent
0.6 - 0.75 Good
0.45 - 0.6 Fair
0.3 - 0.45 Poor
< 0.3 Bad
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Speech Intelligibility
Implementation:
• Eyring/Sabine model
• AURA, Raytracing
Direct Sound Early Reflections / Secondary Sources
Eyring RT/Tail
Time
L
Direct Sound Early Reflections / Secondary Sources
Reflections
Time
L
MTF
MTF
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Speech Intelligibility
Implementation:
• Signal/Noise Ratio
0
0,2
0,4
0,6
0,8
1
-50 -40 -30 -20 -10 0 10 20 30 40 50
STI
S/N
STI as a Function of S/N (Broadband)
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Speech Intelligibility
Implementation:
• Signal Masking
0,7
0,75
0,8
0,85
0,9
0,95
1
45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
STI
Level in dB(A)
STI as a Function of Broadband Level
White
Pink
A-Weighted
f
L
f1 f2 = 2f1
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Speech Intelligibility
Criticism:
• Stepped masking function
• Being revised for new version
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0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 500 1000 1500 2000
ST
I
Delay [ms]
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 500 1000 S
TI
Delay [ms]
Speech Intelligibility
Criticism:
• Echo situation: delay dependency
2 Pulses 3 Pulses
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Speech Intelligibility • Criticism:
• Linearity of frequency response
• Bandwidth of analog measurements
f
L
500 Hz 1000 Hz 2000 Hz 4000 Hz
STIPa signal spectrum
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Speech Intelligibility
Criticism:
• Binaural?
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Latest development in modern measurement tools
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• Software 1 (EASERA)
• Scale Model Measurements
• Absorption Coefficient Measurements
• Transmission Loss Measurements
• Software 2 (EASERA SysTune)
• SSA Filter
• Mobile Devices
• Hardware
• AD/DA transducer AUBION X8
Overview
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Measurement Software EASERA
Graphic user interface to start a measure- ment
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Measurement Module – Measuring Methods EASERA supports all common Measuring Methods
Simple
Reference
Dual-Channel-FFT
Dual-Channel-TDS
Comparison
External Stimulus
Playback
External
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Post Processing - Displays EASERA Post Processing Module, Displays:
• Measures like: EDT, T10, T20, T30, C50, D50, C80, CT, MTF, MTI, STI, STIPa, RaSTI, ALCons, DSPL, TSPL, L50, L80, D/R, G, ST, IACC, LF/LFC (e.g. ISO 3382)
• Statistical Calculation: RMS, Noise Level, Crest Factor, S/N
• Time Domain Displays like: Impulse Response, Step Response , ETC, Schröder, Echogram
• Frequency Domain Displays like: Power Spectrum, Phase, Real & Imaginary Part, Group Delay
• Averaging, Integrating, Smoothing, Differentiating, Resampling
• Tabular View
• Overlay View
• Units like: Volt, Pa, FS, %, W, Ws, dBu, dBV, dBm, dBp, dBSPL, dBFS
• Waterfall
• Spectrogram
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View&Calc Processing
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Post Processing - Editing
www.sda.de
EASERA Editing Functions:
• Editing with User-defined Filters and Windows
• Editing by Data Averaging, Integrating, Smoothing, Differentiating, Resampling, Multiplication, Summation, Division, Subtraction, Power, Interpolation
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Scale Model Measurements
EASERA Scale Model Measurements: - In air up to 192 kHz sample rate: Scale of 1:20
corresponds to 9.6 kHz sample rate => upper limit is 4 kHz octave
- Air attenuation is significant and must be compensated - Requires very low noise floor, since ΔL ~ t - Rescale by changing sample rate according to scale factor
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Air Compensation
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Change of Scaling Factor
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Results of Scale Model Measurements
EASERA Scale Model Measurements:
170 ms at 192 kHz
3.4 s at 9,6 kHz 2.3 s
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Live Sound Measurements
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Live Sound Measurements Typical setup when using speech or music
signals:
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Spectrally Selective Accumulation SSA • Speech or music signal: • Dedicated measurement signals
often not possible to use • Music and/or speech available during
rehearsal, less disturbing • „Non-ideal“ measurement signals
• Irregular in frequency • Irregular in time • No advance knowledge
• => Spectrally Selective Accumulation*:
• Extracts valid data • Rejects noise, interference,
perturbations
Classic Music: Non-Continuous in Frequency, Preferred Tones
Speech: Non-Continuous in Time and Frequency
*Patent pending
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Spectrally Selective Accumulation SSA
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Spectrally Selective Accumulation SSA Signal Threshold Filter (Action 1)
• Data only used when critical S/N reached
• Excludes unexcited frequencies from subsequent processing
• Threshold spectrum can be measured or entered
• For reference and signal spectrum
Rejected
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Spectrally Selective Accumulation SSA Excursion Filter (Action 2):
Compares new transfer function measurement with existing
Deviating values outside tolerance are discarded/suppressed
Provides high immunity against temporary perturbations
Rejected
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Coherence Filter (Action 3):
• Coherence: Linear relationship between input I and output O
Coherent Incoherent Rejected
2
22
O
I
I
OfC
C → 1 for <O/I>² ≈ <O²>/<I²>
C → 0 for <O/I> → 0
C → const for noise floor > 0
Spectrally Selective Accumulation SSA
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SysTune Web Interface
SysTune @ iPad:
- SysTune plug-in with web interface
- Make measurements with SysTune from mobile device
- Control SysTune remotely
- For any platform with a browser
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SysTune Web Interface
How it works: Laptop SysTune
Soundcard
Mobile Device
Wireless Microphone
Sound System
Sound
Input
Output
Control
Data
Reference Input
WLAN
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SysTune Web Interface
Supported Functions:
- Start / Stop Analysis
- Spectrum, IR, TF
- Frequency Resolution
- Capture Overlays
- Rename/Remove
Overlays
- Show/Hide Overlays
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AUBION X.8
Professional Soundcard:
- Fully digital and calibrated
- 8 Inputs
- Integrated with SysTune and EASERA
- Ethernet-based
- Daisy-chaining possible
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AUBION X.8 Features: - 8 Inputs (4 mic/line, 4 line), 2+2 outputs - 2x Ethernet with switch, SPDIF I/O optional - 10 Hz – 20 kHz, Dynamic Range 110 dB - THD < -100 dB, Crosstalk Attenuation > 110 dB - ASIO drivers