SilentGuide
What is loud?
Decibel (dB)
Sound intensity is measured in Decibel (dB). The typically attached (A) shows that the measured level of acoustic pressure was adapted to percipiency of the human ear for different frequencies with the help of an evaluation curve. DB is a logarithmical measure unit; doubled loudness intensity is 3 db higher than its origin. The human ear will not sense this as double as loud.
The intensity depends on the distance to the source. For PC-Systems the noise level is measured at a distance of one meter in a height of one meter. (Futher information on Decibel: Wikipedia)
dB(A) | Subjective sense | Type of noise |
10 | inaudible | breathing in 30cm distance |
20 | extremely quiet | noise of leaves |
30 | very quiet | whisper / own breath |
40 | quiet | silent street |
50 |
| normal talking |
60 | loud | typing on a keyboard |
80 |
| loud speech in 1m distance |
In the following chart you will find information on the change of loudness coming from several alike sources (source: Verax)
Change of | Sound level | Number of alike | Change of |
| Basic loudness | 0 db | 1 | * 1 |
A bit louder | + 1 db | 1.25 | * 1.1 |
Clearly louder | + 3 db | 2 | * 1.4 |
Twice as loud | + 10 db | 10 | * 3 |
Four times louder | + 20 db | 100 | * 10 |
Sone
Sone is a unit of perceived loudness. Loudness is a subjective measure of the sound pressure. One Sone is defined as a tone of 1kHz at 40dB. All Sone values give the subjective measure compared to this tone. If the value is 0.5 Sone you'll find it as half as loud as the 40dB 1kHz tone, if it's 2 Sone you'll find it as double as loud. A mathematical transformation from dB(A) to Sone and vice versa is impossible because the subjective measure depends on the frequency spectrum of the noise. (Further information on Sone: Wikipedia)
The table below shows estimated values for the translation of Sone into db(A) values:
| Sone | estimated db(A) value |
| 0.2 | 21.5 |
| 0.3 | 22.5 |
| 0.4 | 23.5 |
| 0.5 | 24.4 |
| 0.6 | 25.3 |
| 0.7 | 26.3 |
| 0.8 | 27.2 |
| 0.9 | 28.2 |
| 1.0 | 29.2 |
| 1.1 | 30.2 |
| 1.2 | 31.1 |
| 1.3 | 32.0 |
| 1.4 | 33.0 |
| 1.5 | 33.5 |
| 1.6 | 34.8 |
