1. 1 Noise Exposure of Musicians at the National Ballet Orquestra Alberto Behar, Cheng Qian, Willy Wong IBBME University of Toronto Orlando, Feb. - 2010

2. 2 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.

3. 3 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

4. Procedures - Five dosimeters Quest Type 300 Calibrated 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 4

5. 5 Procedures (Cont). - Dosimeter attached to the belt - Microphone attached to the collar opposite to the instrument Special precaution regarding the cable – taped on the back of the player

6. 6 The orchestra pit Overhang Safety net

7. 7 The orchestra pit. Number of tests. Strings Violin 1115 Violin295 Violas76 Cellos76 Basses43 Wood Flutes32 Oboe32 Clarinets33 Bassoons33 Trumpets42 Horns62 Trombone34 Tuba11 Percussion 4 4 Totals6848 Instruments# of players # of tests Instruments# of players # of tests Brasses

8. 8 InstrumentAverageRange 1st Violin86.985.6-88.2 2 nd Violin 87.283.8-91.3 Viola86.884.9-89.1 Cello86.883.1-88.2 Double Bass90.188.3-90.9 Flute93.091.6-94.1 Oboe 88.287.9-885 Clarinet 89.388.5-90.6 Bassoon 88.688.0-89.6 Trumpet 94.294.2-94.2 French Horn 91.090.8-91.2 Trombone 93.092.2-93.7 Tuba 91.8 Percussion 88.688.3 - 90.4 Results from the measurements ( L eq )

9. 9 Sound levels across the pit

10. 10 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)

11. 11 Expressed as L eq,8 L eq, 8 = L eq, t - 10 log(t/T), dBA t = 300 hr/year L eq, 8 = L eq, t - 10 log(300/2000) = L eq, t - 8.2 dBA Normalizing the results 8.2 dBA to be subtracted from the measurement results

12. 12 InstrumentAverage 1st Violin78.9 2 nd Violin 79.2 Viola78.8 Cello78.8 Double Bass81.1 Flute85.0 Oboe 80.2 Clarinet 83.3 Bassoon 80.6 Trumpet 86.2 French Horn 83.0 Trombone 85.0 Tuba 83.8 Percussion 80.6 Normalized results

13. 13 Risk of hearing loss Risk for brass and flute players (85 dBA) after 40 years (ISO 1999)

14. 14 Engineering controls i) Barriers ii) Raisers iii) Adding sound absorption

15. 15 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

16. 16 The end Thank you! Any question?