/ Department of the Built Environment - Unit BPS PAGE 023-11-2017

Room Acoustics

Hearing is Believing? Measuring is Knowing?

/ Department of the Built Environment - Unit BPS PAGE 123-11-2017

Sound Levels on StageMeasurements and Predictions

Remy WenmaekersTU/e, Level Acoustics & Vibration

Measurements of sound levels

PAGE 223-11-2017

[O’brien et al. (2008)]

High strings75 - 95 dB(A)

Brass instr.Wind instr.Percussion80 - 95 dB(A)

Low strings75 - 90 dB(A)

State of the art

PAGE 323-11-2017

• 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)

Playerhigher level

NeighbourHigher level

1,0 mBA

BA

State of the art

PAGE 423-11-2017

• 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 523-11-2017

Sound level prediction model

This image cannot currently be displayed. Ldirect (f,d)

d

Front directingtowards conductor

φ,θLw (f)LI(f,φ,θ)

Learly-refl (f,d)

Ltotal (f,d)

Llate-refl (f)

Ldirect : direct sound levelLearly-refl : early reflected sound levelLlate-refl : late reflected sound levelLtotal : 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) 219-233.

Sound level prediction model

PAGE 623-11-2017

REFLECTEDSOUNDLEVEL

DIRECTSOUNDLEVEL

ROOMACOUSTICS

ORCHESTRA

MUSIC

MUSICIAN

TOTALSOUNDLEVEL

ATTENUATIONORCHESTRA

Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017)Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press

PAGE 723-11-2017

Anechoic recordings of orchestral music- Mahler Symphony no. 1 sample (2:12 min)

[ J. Pätynen, V. Pulkki and T. Lokki 2008]

Anechoic music

PAGE 823-11-2017

Orchestra setup

Nicolai (2016)The influence of acoustics on symphony orchestra musiciansMaster Thesis TU/e

Distances and angles

PAGE 923-11-2017

Right ear: 75 degreeselevation

Both ears:270 degreesazimuth

B

A

Left ear:65 degreeselevation

A or B is close to the acoustic centre

Directivity instrument and ear

PAGE 1023-11-2017

Relative sound intensity LI(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)

HRTF example[https://lmkprod.com]

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, 20–28.

Sound level prediction model

PAGE 1123-11-2017

ROOMACOUSTICS

ORCHESTRA

MUSIC

MUSICIAN

Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017)Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press

Time windows (18 x 12 m2 stage)

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, 776–789. PAGE 1223-11-2017

Source Self

Source other 1

Source other 2

Source other n

Direct sound Others, +/- 3 to 60 ms after direct sound Self

Early reflected Self, +/- 5 to 100 ms after direct sound SelfDirect sound Self, time is 3 ms at 1 m distance

Late reflected Hall, +/- > 100 ms to infinite after direct sound Self

∞

Early reflected Others, +/- 5 to 100 ms after direct sound Self

Source OtherSource Self

1000 300200 500 600400 1000900800700

∞

∞∞

time [ms]

Receiver Self

PAGE 1323-11-2017

delay = time for direct sound to arrive at receiver

Optimised acoustic parameters

delay

103 ms

Sound power measurement

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, 776–789.

10 msafterdelay

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), 892-907.

Sound level prediction model

PAGE 1423-11-2017

ROOMACOUSTICS

ORCHESTRA

MUSIC

MUSICIAN

ATTENUATIONORCHESTRA

Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017)Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press

Occupied stage, direct sound

PAGE 1523-11-2017

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), 4437-4448.

Dammerud and Barron, J. Acoust. Soc. Am. 128, 1755–1765 (2010).

Attenuation of direct sound with floor reflection

Occupied stage, reflected sound

PAGE 1623-11-2017

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), 4437-4448.

Sound level prediction model

PAGE 1723-11-2017

DIRECTSOUNDLEVEL

ATTENUATIONORCHESTRA

ROOMACOUSTICS

ORCHESTRA

MUSIC

MUSICIAN

Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017)Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press

Direct sound level others

PAGE 1823-11-2017

( ) ),(),(lg20),,(),( 1; θθϕ fLdfLdfLdfL earorchmeqdirect ∆+∆+−=

Wenmaekers, Hak: A sound level distribution model for symphony orchestras: Possibilities and limitations. Psychomusicology: Music, Mind, and Brain 25(3) (2015) 219-233.

distance+ angles

Sound level prediction model

PAGE 1923-11-2017

REFLECTEDSOUNDLEVEL

DIRECTSOUNDLEVEL

ATTENUATIONORCHESTRA

ROOMACOUSTICS

ORCHESTRA

MUSIC

MUSICIAN

Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017)Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press

REFLECTED SOUND LEVEL

PAGE 2023-11-2017

11),()(),( ; −+=− dfSTfLdfL dearlywreflearly

11)()()( ; −+=− fSTfLfL dlatewrefllate

Early reflected sound:

Late reflected sound:

Wenmaekers, Hak: A sound level distribution model for symphony orchestras: Possibilities and limitations. Psychomusicology: Music, Mind, and Brain 25(3) (2015) 219-233.

Sound level prediction model

PAGE 2123-11-2017

REFLECTEDSOUNDLEVEL

DIRECTSOUNDLEVEL

TOTALSOUNDLEVEL

ATTENUATIONORCHESTRA

ROOMACOUSTICS

ORCHESTRA

MUSIC

MUSICIAN

Sound levels on stage: Measurements and Predictions

Wenmaekers, Nicolai, Hornikx, Kohlrausch (2017)Why orchestral musicians are bound to wear earplugs Journ. Acoust. Soc. Am., in press

Calculated sound levels

PAGE 2223-11-2017

- A-weighted sound pressure level- Received level at musicians’ ears- Window 2k samples (fs=48kHz)- Sound is anechoic, recorded by

Pätynen et al.

NicolaiThe influence of acoustics on symphony orchestra musiciansMaster Thesis TU/e, 2016

https://youtu.be/30ql7sIyql4

Validation

/ Department of the Built Environment - Unit BPS PAGE 2323-11-2017

- LAeq per 46 excerpts of the 2 minutes- Example shown for cello and trumpet- Trend and level for LAeq well predicted- Activity of trumpet player (and nearby

instruments) visible as maxima

- LAeq for the full movement (2 minutes), for three different stages, 65% of thepositions are predicted within 2 dB deviation

State of the art

PAGE 2423-11-2017

• 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?

Physical measures

/ Department of the Built Environment - Unit BPS PAGE 2523-11-2017

• Available space

• Riser height

• Screens A) a large screen positioned at 0.3 m behind musicianB) 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 roomB) – 6 dB, similar to a theatre stage with curtains

0.75 m1.5 m *

1.5 m2 / musican 2.0 m2 / musican * 2.5 m2 / musican

* Suggested in Dutch regulation

flat

Reference

Results

/ Department of the Built Environment - Unit BPS PAGE 2623-11-2017

For excerpt of Mahler Symphony 1

higher/lower risers

more/lessspace

screensbehind

screenssurround

+6 dB reflectedsound

-6 dB reflectedsound

high strings +/- 0.05 +/- 0.5 -0.7 -2.0 1.6 -0.5low strings +/- 0.1 +/- 0.7 -0.5 -0.9 4.2 -2.4woodwind/brass +/- 0.2 +/- 0.7 -0.6 -2.9 1.7 -0.6

• 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.

Conclusions

/ Department of the Built Environment - Unit BPS PAGE 2723-11-2017

• Sound level prediction model for the symphony orchestra is able to predict LA,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.

Other solutions?

/ Department of the Built Environment - Unit BPS PAGE 2823-11-2017

A screen between you and your instrument

More distance between you and your instrument

or

/ Department of the Built Environment - Unit BPS PAGE 2923-11-2017

See you later ?!

Remy WenmaekersTU/e, Level Acoustics & Vibration