Room Acoustics. Hearing is Believing? Measuring is Knowing? / Department of the Built Environment - Unit BPS PAGE 0

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1 Room Acoustics Hearing is Believing? Measuring is Knowing? / Department of the Built Environment - Unit BPS PAGE 0

2 Sound Levels on Stage Measurements and Predictions Remy Wenmaekers TU/e, Level Acoustics & Vibration / Department of the Built Environment - Unit BPS PAGE 1

3 Measurements of sound levels High strings db(a) Low strings db(a) Brass instr. Wind instr. Percussion db(a) [O brien et al. (2008)] PAGE 2

4 State of the art Orchestral musicians are exposed to equivalent sound levels above 85 db(a), both during individual (often highest) and group rehearsals/performances. In the orchestra: musicians feel their own instrument is not noisy, but it is the neighbouring instruments that cause the problems (Laitinen, 2005) A 1,0 m B A Player higher level Neighbour Higher level B PAGE 3

5 State of the art Orchestral musicians are exposed to equivalent sound levels above 85 db(a), both during individual (often highest) and group rehearsals/performances. In the orchestra: musicians feel their own instrument is not noisy, but it is the neighbouring instruments that cause the problems (Laitinen, 2005) Ear plugs hinder the musical performance and are only used occasionally. Physical measures are often suggested when playing in the orchestra, such as more space, risers, screens and acoustic treatment. But are these measures effective? Can we predict their (in)effectiveness? PAGE 4

6 This image cannot currently be displayed. Sound level prediction model L late-refl (f) L early-refl (f,d) L w (f) L I (f,φ,θ) Front directing towards conductor φ,θ L direct (f,d) L total (f,d) L direct : L early-refl : L late-refl : L total : direct sound level early reflected sound level late reflected sound level total sound level (total = direct, early and late) Wenmaekers, Hak (2015) A sound level distribution model for symphony orchestras: Possibilities and limitations. Psychomusicology: Music, Mind, and Brain 25(3) d PAGE 5

7 Sound level prediction model MUSIC ORCHESTRA ROOM ACOUSTICS MUSICIAN ATTENUATION ORCHESTRA DIRECT SOUND LEVEL REFLECTED SOUND LEVEL TOTAL SOUND LEVEL Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017) Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press PAGE 6

8 Anechoic music Anechoic recordings of orchestral music - Mahler Symphony no. 1 sample (2:12 min) [ J. Pätynen, V. Pulkki and T. Lokki 2008] PAGE 7

9 Orchestra setup Nicolai (2016) The influence of acoustics on symphony orchestra musicians Master Thesis TU/e PAGE 8

10 Distances and angles Right ear: 75 degrees elevation A Left ear: 65 degrees elevation B Both ears: 270 degrees azimuth A or B is close to the acoustic centre PAGE 9

11 Directivity instrument and ear HRTF example [ Relative sound intensity L I (f,φ,θ) Directivity of orchestra instruments in CLF format [Pätynen and Lokki 2010] Directivity of the ear with microphones in front of a HATS [Wenmaekers, 2015] Directivity only taken into account for direct sound (for reflective sound, directivity is neglegible) Wenmaekers, Hak, Hornikx, Kohlrausch (2017). Sensitivity of stage acoustic parameters to source and receiver directivity: Measurements on three stages and in two orchestra pits. Appl. Acoust. 123, PAGE 10

12 Sound level prediction model MUSIC ORCHESTRA MUSICIAN ROOM ACOUSTICS Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017) Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press PAGE 11

13 Time windows (18 x 12 m 2 stage) Source Self Source Other Source Self Source other 1 Source other 2 Source other n Receiver Self Direct sound Self, time is 3 ms at 1 m distance time [ms] Early reflected Self, +/- 5 to 100 ms after direct sound Self Direct sound Others, +/- 3 to 60 ms after direct sound Self Early reflected Others, +/- 5 to 100 ms after direct sound Self Late reflected Hall, +/- > 100 ms to infinite after direct sound Self R.H.C. Wenmaekers, C.C.J.M. Hak, and L.C.J. van Luxemburg, (2012), On measurements of stage acoustic parameters - time interval limits and various source-receiver distances Acta Acustica united with Acustica, 98, PAGE 12

14 Optimised acoustic parameters 103 ms delay 10 ms after delay Sound power measurement delay = time for direct sound to arrive at receiver R.H.C. Wenmaekers, C.C.J.M. Hak, and L.C.J. van Luxemburg, (2012), On measurements of stage acoustic parameters - time interval limits and various source-receiver distances Acta Acustica united with Acustica, 98, R.H.C. Wenmaekers and C.C.J.M. Hak (2015) The sound power as a reference for sound strength (G), speech level (L) and support (ST): uncertainty of laboratory and in-situ calibration. Acta Acustica united with Acustica, 101(5), PAGE 13

15 Sound level prediction model MUSIC ORCHESTRA MUSICIAN ATTENUATION ORCHESTRA ROOM ACOUSTICS Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017) Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press PAGE 14

16 Occupied stage, direct sound Attenuation of direct sound with floor reflection Dammerud and Barron, J. Acoust. Soc. Am. 128, (2010). R.H.C. Wenmaekers, C.C.J.M. Hak, M.C.J. Hornikx (2016). How orchestra members influence stage acoustic parameters on five different concert hall stages and orchestra pits. J. Ac. Soc. Am. 140(6), PAGE 15

17 Occupied stage, reflected sound R.H.C. Wenmaekers, C.C.J.M. Hak, M.C.J. Hornikx (2016). How orchestra members influence stage acoustic parameters on five different concert hall stages and orchestra pits. J. Ac. Soc. Am. 140(6), PAGE 16

18 Sound level prediction model MUSIC ORCHESTRA MUSICIAN ATTENUATION ORCHESTRA DIRECT SOUND LEVEL ROOM ACOUSTICS Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017) Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press PAGE 17

19 Direct sound level others L direct ( d ) + L ( f, d) + L ( f, ) ( f, d) = Leq; 1m( f, ϕ, θ ) 20 lg orch ear θ distance + angles Wenmaekers, Hak: A sound level distribution model for symphony orchestras: Possibilities and limitations. Psychomusicology: Music, Mind, and Brain 25(3) (2015) PAGE 18

20 Sound level prediction model MUSIC ORCHESTRA ROOM ACOUSTICS MUSICIAN ATTENUATION ORCHESTRA DIRECT SOUND LEVEL REFLECTED SOUND LEVEL Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017) Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press PAGE 19

21 REFLECTED SOUND LEVEL Early reflected sound: L ( f, d) = L ( f ) + ST ; ( f, d) 11 early refl w early Late reflected sound: L ( f ) = L ( f ) + ST ; ( f ) 11 late refl w late Wenmaekers, Hak: A sound level distribution model for symphony orchestras: Possibilities and limitations. Psychomusicology: Music, Mind, and Brain 25(3) (2015) d d PAGE 20

22 Sound level prediction model MUSIC ORCHESTRA ROOM ACOUSTICS MUSICIAN ATTENUATION ORCHESTRA DIRECT SOUND LEVEL REFLECTED SOUND LEVEL Sound levels on stage: Measurements and Predictions TOTAL SOUND LEVEL Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017) Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press PAGE 21

23 Calculated sound levels - A-weighted sound pressure level - Received level at musicians ears - Window 2k samples (fs=48khz) - Sound is anechoic, recorded by Pätynen et al. Nicolai The influence of acoustics on symphony orchestra musicians Master Thesis TU/e, 2016 PAGE 22

24 Validation - L Aeq per 46 excerpts of the 2 minutes - Example shown for cello and trumpet - Trend and level for L Aeq well predicted - Activity of trumpet player (and nearby instruments) visible as maxima - L Aeq for the full movement (2 minutes), for three different stages, 65% of the positions are predicted within 2 db deviation / Department of the Built Environment - Unit BPS PAGE 23

25 State of the art Orchestral musicians are exposed to equivalent sound levels above 85 db(a), both during individual (often highest) and group rehearsals/performances. In the orchestra: musicians feel their own instrument is not noisy, but it is the neighbouring instruments that cause the problems (Laitinen, 2005) Ear plugs hinder the musical performance and are only used occasionally. Physical measures are often suggested when playing in the orchestra, such as more space, risers, screens and acoustic treatment. But are these measures effective? Can we predict the (in)effectiveness? PAGE 24

26 Physical measures Available space Reference 1.5 m 2 / musican 2.0 m 2 / musican * 2.5 m 2 / musican Riser height flat 0.75 m 1.5 m * Screens A) a large screen positioned at 0.3 m behind musician B) a hypothetical case with fully surrounding screens Acoustic conditions reflected sound changed relative to a concert hall by A) + 6 db, similar to a small rehearsal room B) 6 db, similar to a theatre stage with curtains * Suggested in Dutch regulation / Department of the Built Environment - Unit BPS PAGE 25

27 Results For excerpt of Mahler Symphony 1 higher/low er risers more/less space screens behind screens surround +6 db reflected sound -6 db reflected sound high strings +/ / low strings +/ / woodwind/brass +/ / Riser height and available space do not significantly influence sound exposure. This is because the direct sound of others only changes slightly. Screens behind musicans are not effective because they only screen some of the musicians and because reflected sound levels are not affected. Hypothetically surrounding screens, that would reduce all other musicians direct sound, would influence sound exposure by 1 to 3 db. Reflected sound only significantly influences sound levels at the low strings because the contribution of own and others direct sound is relatively low. / Department of the Built Environment - Unit BPS PAGE 26

28 Conclusions Sound level prediction model for the symphony orchestra is able to predict L A,eq within 2 db deviation for 65% of the microphone positions taken with a maximum deviation of 6 db. The calculated effectiveness of common control measures to sound exposure of musicians playing in a symphony orchestra is within a limited range of 0.5 to 5 db and in realistic cases below 2 db. The own instrument s direct sound has a large contribution to the sound exposure, when playing in the orchestra and even at home. It seems that orchestral musicians have no other choice than to protect their ears with ear plugs under all circumstances (individual and group playing) if they wish to avoid the risk of developing hearing damage. / Department of the Built Environment - Unit BPS PAGE 27

29 Other solutions? A screen between you and your instrument or More distance between you and your instrument / Department of the Built Environment - Unit BPS PAGE 28

30 See you later?! Remy Wenmaekers TU/e, Level Acoustics & Vibration / Department of the Built Environment - Unit BPS PAGE 29