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A P f R ki fA Performance Ranking of Seven Different Types ofSeven Different Types of Loudspeaker Line ArraysLoudspeaker Line Arrays
D B (Don) Keele JrD. B. (Don) Keele, Jr.DBK Associates and LabsBloomington, IN 47408g , 474www.DBKeele.com(AES Paper Given Nov. 2010)
1Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
OverviewIntroduction
Arrays AnalyzedArrays Not AnalyzedPerformance Parameters EvaluatedA Si l i C di iArray Simulation ConditionsPerformance Ranking
AnalysisAnalysisAnalysis Results and RankingSummarySummary
2Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Arrays Analyzed1. An un‐shaded straight‐line array2. A Hann‐shaded straight‐line arrayg y3. An un‐shaded “J”‐line array with straight top half and circular‐arc bottom half
4. An un‐shaded spiral‐ or progressive‐line array5. An un‐shaded circular‐arc array 6. A Legendre‐shaded circular‐arc CBT array 7. A Legendre‐shaded delay‐curved straight‐line CBT array
3Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Arrays Not Analyzed!Any array that requires complex DSP frequency‐dependent processing.
Other potentially complicated constant beamwidth designs such as:designs such as:
Arrays that maintain a constant acoustic aperture size in wavelengths.gHorbach‐Keele pair‐wise symmetric multi‐way crossover‐based designs.Etc.
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 4
Caution! Disclaimer!Take what you are going to hear in the following presentation with a grain of salt!CBT Constant Beamwidth TransducerCBT = Constant Beamwidth TransducerThe CBT technology was first described by the U.S. Military in a series of JASA papers describing simple y J p p g pspherical‐cap underwater transducers that provide wide‐band extremely constant beamwidth and directivity behavior with virtually no side lobesbehavior with virtually no side lobes.I was the first to apply the CBT concept to loudspeakers.
Therefore I’m biased!!!Therefore, I m biased!!!Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 5
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 6
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 7
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 8
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 9
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 10
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 11
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 12
Array Depictions
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 13
P f P tPerformance Parameters EvaluatedEvaluated
Beamwidth uniformityDirectivity uniformity Vertical sound‐field uniformity
l d l b Polar side lobe suppressionUniformity of polar responseS h d fl f ff i f Smoothness and flatness of off‐axis frequency responseSound pressure rolloff versus distance, and N f l tt if itNear‐far polar pattern uniformity.
14Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Array Simulation ConditionsAll modeled arrays were 2m high and composed of 100 equal‐spaced point sources.q p pEach of the circular‐arc arrays were 60°.No complicated signal processing was permitted p g p g pexcept for frequency‐independent inter‐element shading and delay, plus in‐line equalization to flatten th f t ifi l tithe frequency response at a specific location.All data was calculated at one‐third‐octave intervals over the range of 20 Hz to 20 kHzover the range of 20 Hz to 20 kHz.
15Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Array Rotation Point for PolarsMost arrays were rotated around the front center of the array.
Th i l The circular‐arc arrays were rotated around the arc’s center of
16Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
the arc s center of curvature.
Performance RankingPerformance Ranking
The eight performance parameters were simulated for each array type and then subjectively (by me!) scored on a scale from 1 to 10 with 10 higheston a scale from 1 to 10 with 10 highest.The subjective score of the eight parameters was then used to rank each array with respect to each other for used to rank each array with respect to each other for each parameter.The final array ranking was calculated by adding up the individual performance parameter scores for each array in a table which then determined the final rankingranking.
17Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: Beamwidth UniformityAnalysis: Beamwidth UniformityIdeal Beamwidth
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 18
Analysis: Beamwidth UniformityAnalysis: Beamwidth UniformityUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Un‐Shaded Spiral‐Line Array
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 19
Analysis: Beamwidth UniformityUn‐shaded straight‐line array
20Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: Beamwidth UniformityHann‐shaded straight‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 21
Analysis: Beamwidth UniformityUn‐shaded “J”‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 22
Analysis: Beamwidth UniformityUn‐shaded spiral‐ or progressive‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 23
Analysis: Beamwidth UniformityUn‐shaded circular‐arc array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 24
Analysis: Beamwidth UniformityLegendre‐shaded CBT circular‐arc array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 25
Analysis: Beamwidth UniformityLegendre‐shaded delay‐curved CBT straight‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 26
Beamwidth RankingBeamwidth RankingUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
56 756 7Un‐Shaded Spiral‐Line Array
3Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line Array
3Shaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array
1 24CBT Straight Line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 27
1 24
Analysis: Directivity UniformityAnalysis: Directivity UniformityIdeal Directivityy
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 28
Analysis: Directivity UniformityAnalysis: Directivity UniformityUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Un‐Shaded Spiral‐Line Array
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 29
Analysis: Directivity UniformityUn‐shaded straight‐line array
30Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: Directivity UniformityHann‐shaded straight‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 31
Analysis: Directivity UniformityUn‐shaded “J”‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 32
Analysis: Directivity UniformityUn‐shaded spiral‐ or progressive‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 33
Analysis: Directivity UniformityUn‐shaded circular‐arc array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 34
Analysis: Directivity UniformityLegendre‐shaded CBT circular‐arc array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 35
Analysis: Directivity UniformityLegendre‐shaded delay‐curved CBT straight‐line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 36
Directivity RankingDirectivity RankingUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
67 567 5Un‐Shaded Spiral‐Line Array
3Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line Array
3Shaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array
1 24CBT Straight Line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 37
1 24
Analysis: Sound‐Field Uniformity i h Fwith Frequency
Ideal Vertical Sound‐FieldIdeal Vertical Sound‐Field
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 38
Analysis: Sound Field UniformityAnalysis: Sound‐Field UniformityIdeal Vertical Sound‐Field
Stays the same with frequency!Stays the same with distance!No near-field chaos or disorder!No Lobes!
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 39
Analysis: Sound‐Field UniformityAnalysis: Sound Field UniformityUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Un‐Shaded Spiral‐Line Array
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 40
Analysis: Sound‐Field UniformityUn‐shaded straight‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
41Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: Sound‐Field UniformityHann‐shaded straight‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 42
Analysis: Sound‐Field UniformityUn‐shaded “J”‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 43
Analysis: Sound‐Field UniformityUn‐shaded spiral‐ or progressive‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 44
Analysis: Sound‐Field UniformityUn‐shaded circular‐arc array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 45
Analysis: Sound‐Field UniformityUn‐shaded circular‐arc array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Note near‐field chaos!
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 46
Analysis: Sound‐Field UniformityUn‐shaded circular‐arc array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 47
Analysis: Sound‐Field UniformityLegendre‐shaded CBT circular‐arc array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 48
Analysis: Sound‐Field UniformityLegendre‐shaded delay‐curved CBT straight‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 49
Analysis: Sound‐Field RankingAnalysis: Sound Field RankingUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
47 647 6Un‐Shaded Spiral‐Line Array
5Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line Array
Shaded Delay‐Curved CBT Straight‐Line array
5Un Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
1 23Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 50
1 23
Analysis: Sound‐Field Uniformity
Note: The appendix of my paper has aNote: The appendix of my paper has acomplete set of octave sound‐fieldsf h f H 6 kH !for each array from 125 Hz to 16 kHz!
51Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: Polar Side Lobe SuppressionAnalysis: Polar Side‐Lobe Suppression
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 52
Analysis: Polar Side Lobe SuppressionAnalysis: Polar Side‐Lobe SuppressionBad! Good!
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 53
Analysis: Polar Side‐Lobe SuppressionUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line ArrayAnalysis: Polar Side‐Lobe Suppression
Un‐Shaded Spiral‐Line Array
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
Nov. 4, 2010 AES San Francisco 54Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis: Polar Side‐Lobe SuppressionUn‐shaded straight‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
55Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: Polar Side‐Lobe SuppressionHann‐shaded straight‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 56
Analysis: Polar Side‐Lobe SuppressionUn‐shaded “J”‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 57
Analysis: Polar Side‐Lobe SuppressionUn‐shaded spiral‐ or progressive‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 58
Analysis: Polar Side‐Lobe SuppressionUn‐shaded circular‐arc array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 59
Analysis: Polar Side‐Lobe SuppressionLegendre‐shaded CBT circular‐arc array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 60
Analysis: Polar Side‐Lobe SuppressionLegendre‐shaded delay‐curved CBT straight‐line array
Mid Frequencies (1 kHz) High Frequencies (8 kHz)
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 61
Analysis: Side‐Lobe Supp RankingUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line ArrayAnalysis: Side‐Lobe Supp. Ranking
37 637 6Un‐Shaded Spiral‐Line Array
5Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line Array
Shaded Delay‐Curved CBT Straight‐Line array
5Un Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array g y
1 24Nov. 4, 2010 AES San Francisco 62
1 24Keele ‐ Ranking of Loudspeaker Line Arrays
A l i U if it f V ti lAnalysis: Uniformity of Vertical Polar Response with FrequencyPolar Response with Frequency 250 Hz 500 Hz 1 kHz 2 kHz 4 kHz 8 kHz
250 Hz 500 Hz 1 kHz 2 kHz 4 kHz 8 kHz
Nov. 4, 2010 AES San Francisco 63Keele ‐ Ranking of Loudspeaker Line Arrays
A l i U if it f V ti lAnalysis: Uniformity of Vertical Polar Response with FrequencyPolar Response with Frequency 250 Hz 500 Hz 1 kHz 2 kHz 4 kHz 8 kHz
Bad!
250 Hz 500 Hz 1 kHz 2 kHz 4 kHz 8 kHz
Good! Nov. 4, 2010 AES San Francisco 64Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis: Uniformity of Polar Response with Frequency Ranking
Un‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line ArrayResponse with Frequency Ranking
67 567 5Un‐Shaded Spiral‐Line Array
4Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line Array
Shaded Delay‐Curved CBT Straight‐Line array
4Un Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array g y
1 23Nov. 4, 2010 AES San Francisco 65
1 23Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis: Uniformity of PolarAnalysis: Uniformity of Polar Response with Frequency RankingResponse with Frequency Ranking
Note: The appendix of my paper has Note: The appendix of my paper has a complete set of octave polars for
h f H t 6 kH !66Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
each array from 125 Hz to 16 kHz!
Analysis: Smoothness andAnalysis: Smoothness and Flatness of Off‐Axis Responsep
Ideally, the off‐axis frequencyresponse should be well‐behaved,smooth and flat, and be independentof distance. In order to assess this,the off‐axis frequency response of thethe off‐axis frequency response of thearrays was simulated at two distancesof 3 m and 18 m. Frequencyresponses were simulated at six on‐and off‐axis angles from 0° to 30°,with a step of 6° with the on axis
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 67
with a step of 6 , with the on‐axisresponse equalized flat.
Analysis: Smoothness and Flatness of
Un‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Off‐Axis ResponseUn Shaded Straight Line Array Shaded Straight Line Array Un Shaded J Line Array
Un‐Shaded Spiral‐Line Array
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
Nov. 4, 2010 AES San Francisco 68Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis: Smoothness and Flatness ofAnalysis: Smoothness and Flatness of Off‐Axis Response
Un‐shaded straight‐line array3 m 18 m
69Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: Smoothness and Flatness ofAnalysis: Smoothness and Flatness of Off‐Axis Response
Hann‐shaded straight‐line array3 m 18 m
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 70
Analysis: Smoothness and Flatness ofAnalysis: Smoothness and Flatness of Off‐Axis Response
Un‐shaded “J”‐line array3 m 18 m
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 71
Analysis: Smoothness and Flatness ofAnalysis: Smoothness and Flatness of Off‐Axis Response
Un‐shaded spiral‐ or progressive‐line array3 m 18 m
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 72
Analysis: Smoothness and Flatness ofAnalysis: Smoothness and Flatness of Off‐Axis Response
Un‐shaded circular‐arc array3 m 18 m
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 73
Analysis: Smoothness and Flatness ofAnalysis: Smoothness and Flatness of Off‐Axis Response
Legendre‐shaded CBT circular‐arc array3 m 18 m
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 74
Analysis: Smoothness and Flatness ofAnalysis: Smoothness and Flatness of Off‐Axis Response
Legendre‐shaded delay‐curved CBT straight‐line array
3 m 18 m
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 75
Analysis: Smoothness and Flatness of
Un‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Off‐Axis Response RankingUn Shaded Straight Line Array Shaded Straight Line Array Un Shaded J Line Array
57 6Un‐Shaded Spiral‐Line Array
457 6
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line array
4Un Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
1 23Nov. 4, 2010 AES San Francisco 76
1 23Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis: Sound Pressure LevelAnalysis: Sound Pressure Level vs. DistanceThe sound pressure level (SPL)versus distance of the arrays wasevaluated at octave frequencies of62.5 Hz to 8 kHz. The SPL vs.distance was evaluated at twodistance was evaluated at twodifferent array launch heights: a) thecenter of the array and b) the top ofthe array.
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 77
SPL L h P i t dSPL Launch Points and TrajectoriesTrajectories
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 78
A l i SPL Di tUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Analysis: SPL vs. Distance
Un‐Shaded Spiral‐Line Array
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
Nov. 4, 2010 AES San Francisco 79Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis: SPL vs. DistanceUn‐shaded straight‐line array
From Center From Topp
80Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis: SPL vs. DistanceHann‐shaded straight‐line array
From Center From Topp
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 81
Analysis: SPL vs. DistanceUn‐shaded “J”‐line array
From Center From Topp
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 82
Analysis: SPL vs. DistanceUn‐shaded spiral‐ or progressive‐line array
From Center From Topp
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 83
Analysis: SPL vs. DistanceUn‐shaded circular‐arc array
From Center From Topp
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 84
Analysis: SPL vs. DistanceLegendre‐shaded CBT circular‐arc array
From Center From Topp
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 85
Analysis: SPL vs. DistanceLegendre‐shaded delay‐curved CBT straight‐line array
From Center From Topp
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 86
A l i SPL Di t R kiUn‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Analysis: SPL vs. Distance Ranking
67 567 5Un‐Shaded Spiral‐Line Array
4Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line Array
Shaded Delay‐Curved CBT Straight‐Line array
4Un Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
1 23Nov. 4, 2010 AES San Francisco 87
1 23Keele ‐ Ranking of Loudspeaker Line Arrays
A l i N F P l P ttAnalysis: Near‐Far Polar Pattern UniformityUniformity
The polar pattern of the array was evaluated for itsuniformity with distance.The following graphs show polar pattern shapes andbeamwidth vs frequency data at three distances frombeamwidth vs. frequency data at three distances fromthe array: 2 m, 6 m, and 18 m.Two sets of polars are shown for the three distances atTwo sets of polars are shown for the three distances at800 Hz and 8 kHz.This information yields a reasonable estimate of theychanges in the polar patterns with distance.
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 88
Analysis: Near‐Far Polar Pattern U if it
Un‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Uniformity
Un‐Shaded Spiral‐Line Array
Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line ArrayShaded Delay‐Curved CBT Straight‐Line arrayUn Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
Nov. 4, 2010 AES San Francisco 89Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis: Near‐Far Polar Pattern UniformityUniformity
Un‐shaded straight‐line array2 m 6 m 18 m2 m 6 m 18 m
800 Hz:
8 kHz:
Beamwidth:
90Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Beamwidth:
Analysis: Near‐Far Polar Pattern Uniformity
Hann‐shaded straight‐line arrayUniformity2 m 6 m 18 m2 m 6 m 18 m
800 Hz:
8 kHz:
Beamwidth:
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 91
Beamwidth:
Analysis: Near‐Far Polar Pattern Uniformity
Un‐shaded “J”‐line arrayUniformity2 m 6 m 18 m2 m 6 m 18 m
800 Hz:
8 kHz:
Beamwidth:
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 92
Beamwidth:
Analysis: Near‐Far Polar Pattern Uniformity
Un‐shaded spiral‐ or progressive‐line arrayUniformity2 m 6 m 18 m2 m 6 m 18 m
800 Hz:
8 kHz:
Beamwidth:
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 93
Beamwidth:
Analysis: Near‐Far Polar Pattern Uniformity
Un‐shaded circular‐arc arrayUniformity2 m 6 m 18 m2 m 6 m 18 m
800 Hz:
8 kHz:
Beamwidth:
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 94
Beamwidth:
Analysis: Near‐Far Polar Pattern Uniformity
Legendre‐shaded CBT circular‐arc arrayUniformity2 m 6 m 18 m2 m 6 m 18 m
800 Hz:
8 kHz:
Beamwidth:
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 95
Beamwidth:
Analysis: Near‐Far Polar Pattern Uniformity
Legendre‐shaded delay‐curved CBT straight‐line arrayUniformity2 m 6 m 18 m2 m 6 m 18 m
800 Hz:
8 kHz:
Beamwidth:
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 96
Beamwidth:
Analysis: Near‐Far Polar Pattern U if it R ki
Un‐Shaded Straight‐Line Array Shaded Straight‐Line Array Un‐Shaded “J”‐Line Array
Uniformity Ranking
67 567 5Un‐Shaded Spiral‐Line Array
4Un‐Shaded Circular‐Arc Line Array Shaded Circular‐Arc CBT Line Array
Shaded Delay‐Curved CBT Straight‐Line array
4Un Shaded Circular Arc Line Array Shaded Circular Arc CBT Line Array CBT Straight Line array
1 23Nov. 4, 2010 AES San Francisco 97
1 23Keele ‐ Ranking of Loudspeaker Line Arrays
Analysis Results and yFinal Ranking
98Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis Results and Final yRanking
99Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Analysis Results and Ranking
2134567
100Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Final Ranking (with scores, range 8 ‐80)1. CBT circular‐arc array: 80 2. CBT delay‐curved straight‐line array: 77 y g y 773. Un‐shaded circular‐arc array: 544. Spiral‐line array: 46 p y5. “J”‐line array: 266. Straight‐line array (Hann shaded): 237. Straight‐line array (not shaded): 10
101Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
SummaryThis paper presented simulated performance data that allowed several different types of loudspeaker line arrays to allowed several different types of loudspeaker line arrays to be compared and ranked.
The performance data for all the arrays was subjectively ranked for each performance type on a scale from 1 to 10 and then totaled (scale 8 to 80) for each array to yield the and then totaled (scale 8 to 80) for each array, to yield the final array rankings.
102Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
S C tSummary, Cont.The performance data clearly shows the superiority of the i l d d l d CBT All h circular‐arc and delay‐curved CBT arrays. All the
performance data for these two arrays was extremely uniform and well behaved. The Legendre‐shaded circular‐arc CBT array is clearly the winner here because of its uniformity of coverage and the independence of its performance with distance the independence of its performance with distance. The performance of the delay‐curved straight‐line CBT array is also very uniform and well behaved and nearly y y f ymatches the performance of the circular‐arc CBT array. A distant third to the CBT arrays is the spiral‐line array with th i i “J” li d t i ht li h ldi the remaining J”‐line and straight‐line arrays holding up the bottom of the rankings.
103Keele ‐ Ranking of Loudspeaker Line ArraysNov. 4, 2010 AES San Francisco
Th E dThe End.Ph I’ l d th t t dPhew, I’m glad that guy stopped
talking!!!talking!!!
Nov. 4, 2010 AES San Francisco Keele ‐ Ranking of Loudspeaker Line Arrays 104