CLIO 11

Directivity and 3D BalloonsNews and Updates

17-20 Oct. 2013135th AES ConventionNew York, NY, USA

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Summary

● New redesigned Directivity & 3D Balloons menu● Overlap between directivity and time-frequency

analysis menus has been removed● Menu is completely dedicated to directivity analysis

– Directivity: Single polar scan-lines– 3D Balloons: Sets of 3D polar measurements

● Powerful 3D interpolation and data management ● Flexible export features towards CLF and EASE

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New CLIO 11 Menu Structure

Waterfall, Directivity & 3D

CLIO 11

Wavelet Analysis

CLIO 10

Directivity & 3D Balloons

Time-Frequency Analysis

● Directivity analysis requires as input a set of files (polar measurements)

● Time-Frequency analysis process a single impulse response

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2D Directivity Analysis

● Single plane polar response analysis (2D)

Root file set name

Start, stop and referenceangles

Reference to on axis value

Frequency smoothing

Root file set name

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2D Directivity Analysis

on-axis

Horizontal plane

DUT

Polar scan-line

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2D Directivity Analysis

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2D Directivity Analysis

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2D Directivity Analysis

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3D Balloon Analysis

on-axisdirection

DUT response should besampled over the whole space surrounding the speaker

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Sampling Approaches

● There are several ways to sample the surface of a sphere:● Equiangular sampling● Equal area sampling● Spiral sampling● Random● [...]

● AES standard for loudspeaker directivity measurements recommends the Equiangular Sampling with 5 degrees resolution

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AES56-2008

● AES56-2008: AES standard on acoustics - Sound source modeling - Loudspeaker polar radiation measurements

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Spherical Coordinates

A point in the sphericalcoordinate systemis referenced by threeparameters:

r – sphere radiusθ – polar angleφ – azimuth angle

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Naming Scheme

● CLIO has a naming convention to handle spherical coordinates data:

<filename> φ*100 θ*100.mls

● The file name indicates the direction on the spherical surface

● Angles can be either positive and negative, CLIO 11 will take care of the conversion to positive spherical coordinates

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Why Equiangular Scan-Linesare called Polars?

If we think at the Earth oriented as such the on-axis directionof emission of the loudspeakeris the north pole...

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Why Equiangular Scan-Linesare called Polars?

on-axisdirection

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Why Equiangular Scan-Linesare called Polars?

The horizontal planescan-line runs throughthe poles...

So it is a polar...

If we use the same naming ofEarth scienceswe should call itmeridian

The horizontal (half) polarφ=0 scan-line is the Greenwich meridian

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Equiangular Sampling Single Polar

The horizontal polarφ=0 scan-line

θ angle is rangingfrom 0 (front) to180 (back) with 5 degreeresolution

φ=0; θ=0

φ=0; θ=180

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Equiangular Sampling Scan-Lines

Here is an exampleof a set of scan-linesfor a φ resolutionof 30 degrees

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Equiangular Sampling Example

Resolution: φ 30 degreesθ 5 degrees

Range:0<φ<3600<θ<180

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CLIO 11 Balloon Representation

● CLIO 11 uses as internal reference resolution an equiangular 5 degree resolution● 2664 points● Standard as per AES56 and simulation softwares

● CLIO 11 stores data in third octave bands● From 20 Hz to 20 kHz

● Only magnitude data is shown in form of “inflated” directivity balloons● Balloon radius is proportional to level according to a

given range

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CLIO 11 Input Panel Options

Balloon Data Setvisual help:

Missing data

Balloon Data Setvisual help:

Unused data

Available data

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CLIO 11 Input Panel Options

Dataset Root File name

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CLIO 11 Input Panel Options

Sampling Options:

Equiangular

Free

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CLIO 11 Sampling Options

● Equiangular Sampling● Sphere should be

sampled over a set of half-polars lines

● Resolution of sampling in angles θ and φ is fixed

● Natural extension of single plane scanning

● Free● Minimum 1 point,

maximum 9999 points● At least the on-axis

point should be sampled

● A set of random or custom arranged points can be supplied

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CLIO 11 Input Panel Options

Symmetry options:

None, Semi, Quarter, Axial

+ rotation

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CLIO 11 Input Panel Options

Angular Resolution:

Selectable[5,10,15,30,45,90]degrees

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CLIO 11 Input Panel Options

FrequencySmoothing

Selectable[unsmoothed,1/12,1/6,1/3,1/2 octave]

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CLIO 11 Input Panel Options

Interpolation mode

Selectable[IDW,Bilinear]

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Interpolation Modes

● CLIO 11 internal balloon representation needs full sphere data at 5 degree resolution

● In case of reduced data sets available ● Mirroring data by symmetry● Interpolation of missing data

● CLIO 11 has two interpolation options:● Bilinear interpolation● Inverse Distance Weighting interpolation

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Interpolation Modes

Equiangular Free

Bilinear Y

IDW Y Y

Symmetry Options Y

● In case of Free sampling symmetry options and bilinear interpolation are not available:

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Interpolation - Bilinear

● The missing data is linearly interpolated in two steps

1) Data is interpolated alongthe polar scan-lines (θ angles)

2) Data is interpolatedalong the azimuth(φ angles)

1)

2)

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Interpolation - IDW

● J.Panzer, D.Ponteggia, “Inverse Distance Weighting for Extrapolating Balloon-Directivity-Plots”, presented at 131st AES Convention 2011, New York

● Robust method to extrapolate data from reduced data sets

● No assumptions on data sampling and number of samples

● Minimum 1 sample data

● Smooth balloon surface by algorithm definition

● Weighting factor “u” can be adjusted (typical values 2<u<3)

Interpolated data

Known data points

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3D Import Example – H Symmetry

● Balloon of a H symmetrical box

● Interpolation madeusing bilinear mode

● Measurements madeat 5 degree resolution

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Balloon View

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H Polar Plot

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Data Export

Export Formats

Tabular formats asEASE .xhn ASCII or CLF v2 .tab

Set of impulse responses to be imported by EASE SpeakerLab

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Impulse Responses Export

Time Windowing Options

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