/ 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