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Published byCasandra Isbell Modified about 1 year ago

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Oblique ViewBird’s Eye View

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1. Directional Microphone Arrays a. Most effective at improving speech intelligibility in noise. b. 1dB of DI = 10% HINT improvement 2. Dual Omni Endfire a. Simplest 3. Tri Omni Endfire a. Higher DI 4. Dual Dipole Omni a. Higher DI, Most “Robust” 5. Robustness a. Design of Experiments methods (Deming, Taguchi)

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1. Excessive variation is the root cause of poor manufactured quality. 2. Chasing individual items in/out of specification is counterproductive. Robust Design √

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Factors o Sensitivity matching, Phase matching, In-situ placement Levels o Sensitivity matching: +3dB o Phase matching: +30µs o In-situ: Directional Axis +10º re: horizon Response o Directivity Index o Unidirectional Index

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Directional axis F R 8.5 mm Time Delay Invert Σ Dipole 0 µs Supercardioid 17 µs Cardioid 29 µs

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Degraded Pattern due to Mismatch250Hz500Hz1kHz2kHz4kHz 0.3dB0.6dB1.1dB1.3dB2.4dB 2˚ phase (22µsec) 4˚ phase (22µsec) 8˚ phase (22µsec) 16˚ phase (22µsec) 32˚ phase (22µsec) Amplitude Phase DI=6dB Hypercardioid

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M R 8.5 mm F Σ Invert 4µs Time Delay Directional axis 8µs Time Delay 6dB 2kHz

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Omni Front Dipole Rear Dipole Directional axis FRONT REAR 8.5 mm Σ -47dB 2kHz 250 µsec Delay256 µsec Delay

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Hypercardioid = Max DI Freefield In-situ MRAMRA

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Pinna placementKEMAR at 10º resolution + 10° increments (614 locations) Directional axis DI (and UI) was measured as per ANSI S3.35, Appendix B.

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0° 10° -10° ‘p3’ ‘p2’ ‘p1’ Directional axis In-situ placement

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FR Baseline (SII)

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FMR Baseline (SII)

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O F R Baseline (SII)

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FR Baseline (SII)

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FMR Baseline (SII)

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O F R Baseline (SII)

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10° -10° 30µs -30µs -3dB 3dB dt dA d° Baseline Conditions Optimal Response Surface 5 Factors: F/R Sensitivity Mismatch (13 levels) F/R Time Mismatch (7 levels) Directional Angle on Ear (3 levels) Proprietery Baseline conditions were calculated from in-situ data. FR

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Prescribed Factors and their Levels: 1. Front/Rear Magnitude Mismatch: +3dB in 0.5dB increments. 2. Front/Rear Phase Mismatch: +30µsec in 10µsec increments. 3. Directional Axis Angle: +10° in 10° increments. These are applied to the optimized (baseline) conditions. RunR/F (dB)R/F (usec)Dir Angle (deg)SII DI (dB)SII UI (dB) FR

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10° -10° 30µs -30µs -3dB 3dB dt dA d° Baseline Conditions Optimal Response Surface 5 Factors: F/M Sensitivity Mismatch R/M Sensitivity Mismatch (13 levels) F/M Time Mismatch R/M Time Mismatch (7 levels) Directional Angle on Ear (3 levels) Proprietary Baseline conditions were calculated from in-situ data. FMR

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Prescribed Factors and their Levels: 1. F/M, R/M Magnitude Mismatch: +3dB in 0.5dB increments. 2. F/M, R/M Phase Mismatch: +30µsec in 10µsec increments. 3. Directional Axis Angle: +10° in 10° increments. These are applied to the optimized (baseline) conditions. FMR Replicates Triplicates

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10° -10° 30µs -30µs -3dB 3dB dt dA d° Baseline Conditions Optimal Response Surface 5 Factors: F/O Sensitivity Mismatch R/O Sensitivity Mismatch (13 levels) F/O Time Mismatch R/O Time Mismatch (7 levels) Directional Angle on Ear (3 levels) Baseline conditions (proprietary) were calculated from in-situ data. O F R

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Prescribed Factors and their Levels: 1. F/O, R/O Magnitude Mismatch: +3dB in 0.5dB increments. 2. F/O, R/O Phase Mismatch: +30µsec in 10µsec increments. 3. Directional Axis Angle: +10° in 10° increments. These are applied to the optimized (baseline) conditions. O F R Replicates Triplicates

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FR Baseline

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FMR

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O F R

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FR

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FMR

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O F R

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SII DI = * F/O Sensitivity Mismatch * R/O Sensitivity Mismatch * F/O Time Delay Mismatch * R/O Time Delay Mismatch * F/O Sensitivity Mismatch*R/O Sensitivity Mismatch * F/O Time Delay Mismatch*R/O Time Delay Mismatch * F/O Sensitivity Mismatch * R/O Sensitivity Mismatch * F/O Time Delay Mismatch * R/O Time Delay Mismatch 2 Main Factors Interactions Second Order terms O F R These are coded factor coefficients with actual labels. High coefficients high importance.

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SII UI = * F/O Sensitivity Mismatch * R/O Sensitivity Mismatch * F/O Time Delay Mismatch * R/O Time Delay Mismatch * Directional Axis * F/O Sensitivity Mismatch * R/O Sensitivity Mismatch * F/O Sensitivity Mismatch * R/O Time Delay Mismatch * F/O Time Delay Mismatch * R/O Time Delay Mismatch * R/O Sensitivity Mismatch * R/O Time Delay Mismatch 2 Main Factors Interactions Second Order terms O F R These are coded factor coefficients with actual labels. High coefficients high importance.

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SII DI = * F/M Sensitivity Mismatch * R/M Sensitivity Mismatch * F/M Time Delay Mismatch * R/M Time Delay Mismatch * Directional Axis Angle * F/M Sensitivity Mismatch*R/M Time Delay Mismatch * F/M Time Delay Mismatch * R/M Time Delay Mismatch * Directional Axis Angle 2 Main Factors Interactions Second Order terms FMR These are coded factor coefficients with actual labels. High coefficients high importance.

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SII UI = * F/M Sensitivity Mismatch * R/M Sensitivity Mismatch * F/M Time Delay Mismatch * R/M Time Delay Mismatch * Directional Axis Angle * F/M Sensitivity Mismatch * R/M Sensitivity Mismatch * F/M Time Delay Mismatch * Directional Axis Angle 2 Main Factors Interactions (none) Second Order terms FMR These are coded factor coefficients with actual labels. High coefficients high importance.

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SII DI = * R/F Sensitivity Mismatch * R/F Time Delay Mismatch * Directional Axis Angle * R/F Sensitivity Mismatch * R/F Time Delay Mismatch * R/F Time Delay Mismatch * Directional Axis Angle 2 Main Factors Interactions Second Order terms FR These are coded factor coefficients with actual labels. High coefficients high importance.

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SII UI = * R/F Sensitivity Mismatch * R/F Time Delay Mismatch * Directional Axis Angle * R/F Time Delay Mismatch * Directional Axis Angle 2 Main Factors Interactions (none) Second Order terms FR These are coded factor coefficients with actual labels. High coefficients high importance.

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FR Correlation Grid

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FMR

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O F R

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The following plots depict the directional performance across the factors and their levels. ‘Yellow’ shows: DI SII >4dB and UI SII >6dB. Propagation of Error (POE)<0.8dB. 95% confidence intervals. “Robustness”. O F R

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O F R Desired Operating Conditions: POE less than 0.75dB.

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O F R Desired Operating Conditions: POE less than 0.75dB.

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O F R Desired Operating Conditions: POE less than 0.75dB.

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O F R Desired Operating Conditions: POE less than 0.75dB.

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O F R Desired Operating Conditions: POE less than 0.75dB.

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The following plots depict the directional performance across the factors and their levels. ‘Yellow’ shows: DI SII >2dB and UI SII >3dB*. Propagation of Error (POE)<0.8dB. 95% confidence intervals. “Robustness”. FMR *Basically, we had to lower the target in order to get yellow

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FMR Desired Operating Conditions: POE = 2.4dB. POE = 3.1dB.

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FMR Desired Operating Conditions: POE = 2.4dB. POE = 3.1dB.

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FMR Desired Operating Conditions: POE = 2.4dB. POE = 3.1dB.

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FMR Desired Operating Conditions: POE = 2.4dB. POE = 3.1dB.

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The following plots depict the directional performance across the factors and their levels. ‘Yellow’ shows: DI SII >4dB and UI SII >6dB. Propagation of Error (POE)<0.8dB. 95% confidence intervals. “Robustness”. FR

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FR Preferred Operating Conditions: POE SIIDI ~ 1.3dB. POE SIIUI ~ 2.5dB.

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1. Summary a. Dual Omni Endfire Decent POE, Decent SII DI & SII UI, not robust. b. Tri Omni high POE, low SII DI, low SII UI, not robust. c. DDO lowest POE, highest SII DI & SII UI, most robust… 2. In-situ performance a. Directional Axis Angle optimal from -5° to -10° Thank you for your kind attention.

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