Building acoustics measurements: an innovative solution

with automatic recognition and optimized workflow

Wespac 2015 Paper

E. Aflalo, P. Pischedda

ACOEM, 200 Chemin des Ormeaux, 69578 Limonest, France.

WWW.ACOEMGROUP.COM

THE NEW 01dB

SMART BUILDING ACOUSTICS SOLUTION

01dB SMART BUILDING ACOUSTICS SOLUTION

Description of the automatic measurement types recognition (source, receive, reverberation time interrupted or impulsive, impact

noise, background)

Classical in situ building acoustics measurement for assessing the acoustic

performance of buildings

01dB SLM + omnidirectional sound source needed

Basics

Real time frequency analysis (1/1 or 1/3 oct) with time history to

compare levels over time to specific Triggers

Advanced Trigger feature

L1 RECOGNITION

1Recognition of the measurements in the source room (L1 or

reverberation time)

𝐿𝑤 = 𝐿1 − 10 𝑙𝑜𝑔𝑇

𝑇𝑜+ 10 𝑙𝑜𝑔

𝑉

𝑉𝑜− 13

From the ISO 3743-2 Standard:

In this standard,

Lw: sound power level of the sound source

To = 1 sec; Vo = 1 m3

T: reverberation time of the room

V: volume of the room

L1 RECOGNITION

1Recognition of the measurements in the source room (L1 or

reverberation time)

For example classical values in buildings:

• 25<V<75 m3 13<10*logV<19

• 0.5<T<2.5 sec -3<10*logT<4

And

Knowing the sound power level of the source for

each 1/N octave band

𝐿𝑤 + 4 > 𝐿1 > 𝐿𝑤 − 9,

L1 RECOGNITION

1Recognition of the measurements in the source room (L1 or

reverberation time)

60

70

80

90

100

110

120

130Lw Battery powered non linear pink 70 Hz - 7k Hz 0dB Lw+3 Lw-9

L2 RECOGNITION

2 Recognition of the measurements in the receiving room (L2)

𝐿2 = 𝐿1 – 𝐷𝑛𝑇 + 10 log𝑇

0.5,

Where DnT is the sound insulation value per 1/N octave of the

device under test.

Considering usual performance of buildings:

lowest performance device (DnTMin)

highest performance device (DnTMax)

0.5<T<2.5 sec 0<10*logT/0.5<7

𝐿𝑤 − 𝐷𝑛𝑇𝑀𝑎𝑥 – 9 < 𝐿2 < 𝐿𝑤–𝐷𝑛𝑇𝑀𝑖𝑛 + 11,

Li RECOGNITION

3 Recognition of Li impact noise in the receiving room

𝐿𝑖 = 𝐿𝑛𝑇 + 10 ∗ log𝑇

0.5,

Considering usual performance of buildings:

lowest performance device (LnTMax)

highest performance device (LnTMin)

0.5<T<2.5 sec 0<10*logT/0.5<7

𝐿𝑛𝑇𝑀𝑖𝑛 − 7 < 𝐿𝑖 < 𝐿𝑛𝑇𝑀𝑎𝑥,

Li based on frequencies not excited by the sound source.

Using trigger on the following frequencies: 10 Hz (1/3 oct) or 8 Hz (1/1 oct).

IMPULSIVE TR RECOGNITION

4 Recognition of impulsive reverberation time

𝐿𝐶𝑝𝑘 𝑓𝑜𝑟 𝑖𝑚𝑝𝑢𝑙𝑠𝑒 𝑅𝑇 > 𝐿𝐶𝑝𝑘𝑀𝑎𝑥 + 3 ,

Considering the performance of the sound source (LCpkMax evaluated as

Lw + 4), if during a measurement:

𝐿𝐶𝑝𝑘 > 𝐿𝑤 + 7,

5 Recognition of background noise

If none of the previous criteria is satisfied, the

instrument proposes to classify the

measurement as background noise.

EXAMPLE OF EXTREMA

EXTREMA TABLE FOR THE DETERMINATION OF THE TRIGGER

LEVELS (simulations according to ISO 12354)

F [Hz] L2 Min L2 Max L1 Min Li Min Li Max

16 -15,0 13,0 1,0 56,0 80,0

20 4,0 31,0 21,0 55,0 78,0

25 13,0 39,0 31,0 54,0 77,0

31,5 31,0 58,0 51,0 53,0 76,0

40 39,0 67,0 61,0 56,0 80,0

50 44,8 72,8 68,8 55,0 78,0

63 46,1 75,1 74,1 54,0 77,0

80 47,5 77,5 79,5 53,0 76,0

100 58,7 88,3 93,1 52,4 75,3

125 59,1 87,0 96,3 47,9 67,8

160 55,4 87,7 98,4 44,2 66,1

200 58,6 90,3 105,5 41,7 65,6

250 55,8 87,1 104,8 35,7 63,6

315 49,0 82,1 101,1 31,6 63,5

400 46,9 80,9 102,0 28,6 63,5

500 44,3 77,3 101,4 25,6 63,5

630 38,4 71,4 97,5 17,6 60,5

800 36,6 69,7 97,8 10,6 59,5

1000 35,6 68,7 98,7 5,6 55,5

1250 28,6 62,7 94,6 4,7 51,6

1600 27,9 65,2 96,6 3,7 46,6

2000 27,7 67,3 98,2 3,8 41,7

2500 24,1 68,7 96,6 2,7 39,7

3150 19,5 66,9 94,0 2,7 35,6

4000 19,5 66,0 97,3 2,7 33,6

5000 13,6 60,9 95,5 0,6 30,5

SUMMARY

Graphical summary

0.0

20.0

40.0

60.0

80.0

100.0

120.0

[dB

]

F [Hz]

L2 Min (Lw-DnTMax-12)

L2 Max (Lw – DnTMin +10)

Lw-9 (L1 Min)

Li Min (LnTmin -7)

LiMax (LnTMax)

Li recognition

L1 recognition

L2 recognition

DEFAULT DETECTION PARAMETERS

6 DEFAULT DETECTION PARAMETERS (with our 01dB source)

Event Above @ 1/3oct default_BA_1_3

Above at 1/1 oct Default_BA_1_1

1 40 dB@500 Hz 45 dB@500 Hz 2 40 dB@500 Hz and pre+post-trigger 45 dB@500 Hz and pre+post-trigger 3 50 dB@10 Hz 50 dB@8 Hz 4 85 dB@1 kHz 90 dB@1 kHz 5 128 dB@LCPk 128 dB@LCPk

7 PRIORITY FOR RECOGNITION (“IF”)

Priority Detected event Measurement type 1 5 RT impulse 2 1+2+4 L1 3 1+2+4 then none RT interrupted 4 3 Li 5 1+2 L2 6 None Background noise

PRACTICAL USE ON 01dB SLM

8 PRACTICAL USE OF THE SLM with 3 BUTTONS

CONCLUSION

INNOVATIVE AUTOMATIC DETECTION TECHNIQUE,

PATENT PENDING

Facilitate the Acquisition process

Optimize the measurement organization

Solution compatible with any source

Building Acoustics module on FUSION or DUO

THANKS

WWW.ACOEMGROUP.COM