CLIO 11. Directivity and 3D Balloons News and Updates Oct th AES Convention New York, NY, USA

Transcription

1 CLIO 11 Directivity and 3D Balloons News and Updates Oct th AES Convention New York, NY, USA

2 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 2

3 New CLIO 11 Menu Structure CLIO 10 CLIO 11 Waterfall, Directivity & 3D Directivity & 3D Balloons Wavelet Analysis Time-Frequency Analysis Directivity analysis requires as input a set of files (polar measurements) Time-Frequency analysis process a single impulse response 3

4 2D Directivity Analysis Single plane polar response analysis (2D) Root file set name Start, stop and reference angles Reference to on axis value Frequency smoothing 4

5 2D Directivity Analysis Horizontal plane on-axis DUT Polar scan-line 5

6 2D Directivity Analysis 6

7 2D Directivity Analysis 7

8 2D Directivity Analysis 8

9 3D Balloon Analysis DUT response should be sampled over the whole space surrounding the speaker on-axis direction 9

10 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 10

11 AES AES : AES standard on acoustics - Sound source modeling - Loudspeaker polar radiation measurements 11

12 Spherical Coordinates A point in the spherical coordinate system is referenced by three parameters: r sphere radius θ polar angle φ azimuth angle 12

13 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 13

14 Why Equiangular Scan-Lines are called Polars? If we think at the Earth oriented as such the on-axis direction of emission of the loudspeaker is the north pole... 14

15 Why Equiangular Scan-Lines are called Polars? on-axis direction 15

16 Why Equiangular Scan-Lines are called Polars? The horizontal plane scan-line runs through the poles... So it is a polar... If we use the same naming of Earth sciences we should call it meridian The horizontal (half) polar φ=0 scan-line is the Greenwich meridian 16

17 Equiangular Sampling Single Polar The horizontal polar φ=0 scan-line θ angle is ranging from 0 (front) to 180 (back) with 5 degree resolution φ=0; θ=180 φ=0; θ=0 17

18 Equiangular Sampling Scan-Lines Here is an example of a set of scan-lines for a φ resolution of 30 degrees 18

19 Equiangular Sampling Example Resolution: φ 30 degrees θ 5 degrees Range: 0<φ<360 0<θ<180 19

20 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 20

21 CLIO 11 Input Panel Options Balloon Data Set visual help: Missing data Available data Unused data 21

22 CLIO 11 Input Panel Options Dataset Root File name 22

23 CLIO 11 Input Panel Options Sampling Options: Equiangular Free 23

24 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 24

25 CLIO 11 Input Panel Options Symmetry options: None, Semi, Quarter, Axial + rotation 25

26 CLIO 11 Input Panel Options Angular Resolution: Selectable [5,10,15,30,45,90] degrees 26

27 CLIO 11 Input Panel Options Frequency Smoothing Selectable [unsmoothed, 1/12,1/6,1/3, 1/2 octave] 27

28 CLIO 11 Input Panel Options Interpolation mode Selectable [IDW,Bilinear] 28

29 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 29

30 Interpolation Modes In case of Free sampling symmetry options and bilinear interpolation are not available: Equiangular Bilinear Y IDW Y Symmetry Options Y Free Y 30

31 Interpolation - Bilinear The missing data is linearly interpolated in two steps 1) Data is interpolated along the polar scan-lines (θ angles) 2) Data is interpolated along the azimuth (φ angles) 2) 1) 31

32 Interpolation - IDW J.Panzer, D.Ponteggia, Inverse Distance Weighting for Extrapolating Balloon-DirectivityPlots, 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 Interpolated data Known data points Weighting factor u can be adjusted (typical values 2<u<3) 32

33 3D Import Example H Symmetry Balloon of a H symmetrical box Interpolation made using bilinear mode Measurements made at 5 degree resolution 33

34 Balloon View 34

35 H Polar Plot 35

36 Data Export Export Formats Tabular formats as EASE.xhn ASCII or CLF v2.tab Set of impulse responses to be imported by EASE SpeakerLab 36

37 Impulse Responses Export Time Windowing Options 37

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