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Know-how: dB and Sone
Learn more about dB and Sone
| Measurement distance |
In the Shuttle Acoustics Lab sound pressure measurements are carried out at a distance of 50 cm. However, decrease these values by 6 dB, if you want to compare them with other measurements, which have been made at a distance of 1 meter. |
Sound pressure
Unit: dB |
The sound pressure level is a measure of acoustic force per unit area and is calculated in dB. Each time the distance doubles 6 dB are "lost". A given sound pressure level without the distance of the measurement to the specific sound source is useless, except you want to compare measurements which have been made under the same circumstances. |
A-weighted Sound pressure
Unit: dBA |
The human ear does not respond equally to all frequencies: we are much more sensitive to sounds in the frequency range about 1 kHz to 5 kHz than to very low or high frequency sounds. For this reason, sound meters are usually fitted with a filter whose response to frequency is a bit like that of the human ear. If the "A weighting filter" is used, the sound pressure level is given in units of dB(A) or dBA. |
Loudness
Unit: Sone |
In acoustics, loudness is a subjective measure of the sound pressure. The number of sones to a phon was chosen so that a doubling of the number of sones sounds to the human ear like a doubling of the loudness. The study of apparent loudness is included in the topic of psychoacoustics. |
Conversion table
|
Sone |
dBA |
| 0.2 |
21 ~ 21.5 |
| 0.3 |
22.5 ~ 24.5 |
| 0.4 |
23.5 ~ 25 |
| 0.5 |
25 ~ 26 |
| 0.6 |
25.5 ~ 27 |
| 0.7 |
28 ~ 29 |
| 0.8 |
28.5 ~ 29.5 |
| 0.9 |
30 |
| 1.1 |
31 |
| 1.2 |
30.5 ~ 33 |
| 1.3 |
32 ~ 34 |
| 1.4 |
33 |
| 1.5 |
32.5 ~ 35 |
| 1.6 |
33 ~ 35 |
| 1.7 |
34 |
| 1.8 |
33.4 ~ 36 |
| 1.9 |
35.5 ~ 36 |
| 2.0 |
37.5 |
| 2.1 |
38 |
| 2.2 |
35.5 |
| 2.3 |
38 ~ 39 |
| 2.4 |
38 ~ 40 |
| 2.5 |
38.8 |
| 2.6 |
39 ~ 40 |
| 2.8 |
40 |
| 3.0 |
40 |
| 3.1 |
44.5 |
| 3.9 |
45 ~ 46 |
How noisy is a jet aircraft?
|
Examples |
Sound Pressure
Level dB SPL |
| Jet aircraft, 30 m away |
140 |
| Threshold of pain |
130 |
| Threshold of discomfort |
120 |
| Chainsaw 1m distance |
110 |
| Disco, 1 m from speaker |
100 |
| Diesel truck, 10 m away |
90 |
| Kerbside of busy road, 5 m |
80 |
| Vacuum cleaner, distance 1 m |
70 |
| Conversational speech, 1m |
60 |
| Average home |
50 |
| Quiet library |
40 |
| Quiet bedroom at night |
30 |
|
Background in TV studio |
20 |
| Rustling leaf |
10 |
| Threshold of hearing |
0 |
Source: http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm |
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