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Roadside Measurement of Truck Noise Source Distributions Paul Donavan Bruce Rymer ADC40 Summer Meeting San Luis Obispo, CA July 22-25, 2007 Beam Forming Applied to Trucks Test Track Environment 50 mph Cruise 5900 Truck 10 10 9 10 8

SLIDE 1

Roadside Measurement of Truck Noise Source Distributions

Paul Donavan Bruce Rymer

ADC40 Summer Meeting San Luis Obispo, CA July 22-25, 2007

SLIDE 2

Beam Forming Applied to Trucks

Test Track Environment

SLIDE 3

10 dB

50 mph Cruise

5900 Truck

100 1000 10000 10

Frequency, Hz

SLIDE 4

~6ft ~4-5.2 m say 4.6m ~6ft ~4-5.2 m say 4.6m

Engine Noise from Underneath Cab Tire Tread Passing Frequency

5900 Truck 50 mph Cruise – 416 Hz

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

Frequency, Hz

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

Frequency, Hz

SLIDE 5 10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10 (103)Spectral Density re 20 muPa in 1 Hz Band at Time of Max OASPL frequency

~6ft ~4-5.2 m say 4.6m ~6ft ~4-5.2 m say 4.6m

Engine Noise from wheel well Engine Noise from Underneath Cab (note lower level compared to next slide) Reflection of Engine Noise

5900 Truck 50 mph Cruise – 884 Hz

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

Frequency, Hz

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

Frequency, Hz

SLIDE 6

~6ft ~4-5.2 m say 4.6m ~6ft ~4-5.2 m say 4.6m

5900 Truck 50 mph Cruise – 960 Hz

1st Harmonic of tread passage frequency for G167 drive axle tire

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

Frequency, Hz

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

10 1 10 2 10 3 10 4 10 6 10 7 10 8 10 9 10 10

100 1000 10000 10

Frequency, Hz

SLIDE 7

Beam Forming Applied to Trucks

Roadside Environment

SLIDE 8

Test Site Layout

V~ 50-60 mph 44 ft (0.5 sec @ 60 mph) Radar Gun w/operator (spotter) Still Camera w/operator Video Camera unattended 50 ft 25 ft 25 ft Mic 1 Mic 2 Array Array Operator Microphone Operator Photo Cells 4 ft 12 ft V~ 50-60 mph 44 ft (0.5 sec @ 60 mph) Radar Gun w/operator (spotter) Still Camera w/operator Video Camera unattended 50 ft 25 ft 25 ft Mic 1 Mic 2 Array Array Operator Microphone Operator Photo Cells 4 ft 12 ft

SLIDE 9

Veolia Test Site

101.4 dBA

SLIDE 10

Papas Taverna Site

103.9 dBA

SLIDE 11

Rockin H Ranch Site

99.1 dBA

SLIDE 12

Measurements

Controlled passbys & OBSI
Conventional statistcal passbys at 25 & 50 ft
Beam-forming of passby – heavy trucks

56 at Veolia site 59 at Papas site 95 at Rockin H site + Some medium trucks & cars at each

SLIDE 13

OBSI & 25 ft Controlled Passby

45 50 55 60 65 70 75 80 85 90 95 100 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000

1/3 Octave Band Center Frequncy, Hz Noise Level, dBA

Papas 25 ft Veolia 25 ft Rockin H 25 ft Papas OBSI Veolia OBSI Rockin H OBSI

SLIDE 14

Overall OBSI & Passby Levels

65 70 75 80 85 90 95 100 105 110

OBSI PBY 25 ft PBY 50 ft Noise Level, dBA

Veolia Papas Rockin H

SLIDE 15

Rockin H Site – Heavy Trucks at 25ft

80 82 84 86 88 90 92 94 96

40 42 44 46 48 50 52 54 56 58 60 62 64 66 68

Speed, m ph

Sound Pressure Level, dBA

M easured Curve Fit (Only)

SLIDE 16

Heavy Truck Curve Fits – 25 ft

80 82 84 86 88 90 92 94 96 40 45 50 55 60 65 70

Speed, m ph Sound Pressure Level, dBA Rockin H Papas Veolia

SLIDE 17

Truck REMELs at 50 ft

78 80 82 84 86 88 90 92 94 40 45 50 55 60 65 70

Speed, m ph Sound Pressure Level, dBA REM ELS Data Base Rockin H Veolia Papas

SLIDE 18

OBSI, Passby Levels & Truck Levels

65 70 75 80 85 90 95 100 105 110

OBSI PBY 25 ft PBY 50 ft Truck Curve Fit at 25 ft Truck "REMELS" Noise Level, dBA Veolia Papas Rockin H

SLIDE 19

Loudspeaker Spatial Calibration

3 ft Loudspeaker

SLIDE 20

Apparent Ground Plane 4m 3m 2m 1m 0m

C/L

+7m

Speaker at 1000 Hz

SLIDE 21

Speaker at 2500 Hz

Apparent Ground Plane

SLIDE 22

Apparent Ground Plane

Speaker at 500 Hz

SLIDE 23

Apparent Ground Plane

Speaker at 315 Hz

SLIDE 24

Passby Array Processing

Determined time of maximum A-weighted

passby

Centered analysis at – 0.1 to +0.1 second

about time of maximum

Analysis window of 0.2 seconds or about

64

SLIDE 49

Truck at Veolia Site – 2500 Hz

71

SLIDE 50

Truck at Veolia Site – 2500 Hz

71

SLIDE 51

Summary

Reviewed over 45 passbys to date

Almost universally show loudest sources at the ground or within 1m Drive axle tire noise appears to dominate Engine noise at high frequency

Next steps

Analyze in more detail interesting cases – higher up source regions Develop method for quantifying source vertical distributions

SLIDE 52

Veolia Site – Heavy Trucks at 25ft

80 82 84 86 88 90 92 94 96 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68

Speed, m ph Sound Pressure Level, dBA Measured Curve Fit (Only)

SLIDE 53

Papas Site – Heavy Trucks at 25ft

80 82 84 86 88 90 92 94 96 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68

Speed, m ph

Sound Pressure Level, dBA M easured Curve Fit (O nly)

SLIDE 54

Brown Lane Brazil Veolia Rt 116 Field Gate Papa’s 6220 Lakeville Rockin H Pegasus Vineyard

New AC Oldest AC Newer AC Older AC

Potential Test Sites Lakeville Hwy

Lakeville Rd 101.4 dBA 103.9 dBA 99.1 dBA

SLIDE 55

OBSI & 50 ft Controlled Passby

45 50 55 60 65 70 75 80 85 90 95 100 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000

1/3 Octave Band Center Frequncy, Hz Noise Level, dBA

Papas 50 ft Veolia 50 ft Rockin H 50 ft Papas OBSI Veolia OBSI Rockin H OBSI