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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?