Post on 01-Feb-2016
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Noise Exposure of Musicians at the National Ballet Orquestra
Alberto Behar, Cheng Qian, Willy WongIBBME
University of Toronto
Orlando, Feb. - 2010
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Facts
- The National Ballet has a 68 players strong orchestra.
- They are active 300 hr/year. (performances and rehearsals).
- Performances are in the Four Seasons Centre for the Performing Arts in Toronto, a new Opera and Ballet house that opened in 2006.
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The Survey
- At the request of the Ballet Management
- Presumption: risk of hearing loss, since levels may exceed 95 dBA
- Assessment: performing noise exposure level measurements
- During 10 performances of Sergei Prokofiev’s “Romeo and Juliet”, a particularly loud, 3 hour piece of ballet music
Procedures
- Five dosimeters Quest Type 300Calibrated at the Lab using QuestSuite soft and in the field using B&K calibrator 4230.
- Procedures as per CSA Z107.56 3 dB exchange rate, measuring Leq, dBA, slow
- Five players each time, some of them more than once
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Procedures (Cont).
- Dosimeter attached to the belt
- Microphone attached to the collar opposite tothe instrument
Special precaution regarding the cable – taped on the back of the player
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The orchestra pit
Overhang
Safety net
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The orchestra pit.The orchestra pit.
Number of tests.
Strings
Violin 1 11 5
Violin2 9 5
Violas 7 6
Cellos 7 6
Basses 4 3
Wood
Flutes 3 2
Oboe 3 2
Clarinets 3 3
Bassoons 3 3
Trumpets 4 2Horns 6 2Trombone 3 4Tuba 1 1
Percussion 4 4
Totals 68 48
Instruments # of players
# of tests
Instruments # of players
# of tests
Brasses
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Instrument Average Range1st Violin 86.9 85.6-88.22nd Violin 87.2 83.8-91.3
Viola 86.8 84.9-89.1Cello 86.8 83.1-88.2
Double Bass 90.1 88.3-90.9Flute 93.0 91.6-94.1Oboe 88.2 87.9-885
Clarinet 89.3 88.5-90.6Bassoon 88.6 88.0-89.6Trumpet 94.2 94.2-94.2French Horn 91.0 90.8-91.2
Trombone 93.0 92.2-93.7Tuba 91.8
Percussion 88.6 88.3 - 90.4
Results from the measurements (Leq)
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Sound levels across the pit
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Repeatability
a) Same instrument and player: within 2dBA
c) Larger variations within same section across performances, especially strings (up to 8 dBA)
b) Only exception: Percussionist (3 dBA)
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Expressed as Leq,8
Leq, 8 = Leq, t - 10 log(t/T), dBA
t = 300 hr/year
Leq, 8 = Leq, t - 10 log(300/2000)
= Leq, t - 8.2 dBA
Normalizing the results
8.2 dBA to be subtracted from the measurement results
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Instrument Average1st Violin 78.92nd Violin 79.2
Viola 78.8Cello 78.8
Double Bass 81.1Flute 85.0Oboe 80.2
Clarinet 83.3Bassoon 80.6Trumpet 86.2French Horn 83.0
Trombone 85.0Tuba 83.8
Percussion 80.6
Normalized results
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Risk of hearing loss
Risk for brass and flute players (85 dBA) after 40 years (ISO 1999)
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Engineering controls
i) Barriers
ii) Raisers
iii) Adding sound absorption
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1. Must be comfortable
2. Must have a relatively small attenuation
3. Must have flat attenuation
Hearing Protectors
…and of course
MUST BE PART OF A HEARING CONSERVATION PROGRAM
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The end
Thank you!
Any question?