Sound power, sound pressure: how one measures the volume?
Yoga relaxation exercises is vacuumed while hardworking -. Quite as noise are not yet present vacuum cleaner
. But the manufacturers can be some incident to lower the noise level of the device
A second way to research more about what the volume of vacuum cleaners, is located in the Internet product descriptions of these devices to display. Since there are in addition to the requirements prescribed by law information in product data sheets and EU energy labels still test magazines and comparison portals , where readers themselves can have an idea of the volume of the device by means of various measurements.
The disadvantage of all these descriptions is that one hardly ever one for the buyer of a vacuum cleaner understandable explanation gets the volume readings. And that's what we want to give you here on our website. Whether sound pressure, sound power or pressure level: if you want to get more information 'to simply look at the following table.
sound power
The sound power is an acoustic size. It is independent of the closer or further distance of an observer and the nature of the surrounding space. When I turn on a vacuum cleaner, so it's always the same sound energy per unit of time from, whether I stand next to him or 2 rooms next bin or stand in the basement. Sound energy per unit of time: this is the sound power. Because of the independence of the sound power of the Distance to the observer and the space character to the sound source around is their indication to the user of a vacuum cleaner extremely useful. The sound power so you have a really objective indicator of the volume of a vacuum cleaner.
Sound power level
This power (as an energy / time) is measured in watts. On the energy label of the vacuum cleaner is in volume but not "watts", but always the term "DB" or "dB (A)" or " decibel ". The reason for this is that instead of the pure sound performance is indicative of a water level from which one can see the ratio of the current value to a certain base value.Just as with a flood the water level "about 0" (with a specified null value) indicating so, the procedure even when the sound power and thus comes to the sound power level .
So this is the actual sound power in relation to a lower limit (this reference value was set at 1 picowatt) and thus becomes a dimensionless number, which with the addition of "decibel" or "dB" is specified. How this "comparison" or the exact formula looks for the sound power level, you can for example in Wikipedia (link is external)read. In any case, one should always think in sound power level because this indicates the distance to a base value, which is why you often "adding re dB (A) 1 pW " place, which means "A-weighted sound power level based on a picowatt" ie.
What this means, "A" in dB (A)? It refers to the use of a specific frequency filter, which is prescribed in the measuring process. In all household and garden tools (link is external)is such a frequency filter used (the sound perception is so highly dependent on frequency!), And mainly the A-level has prevailed.
SPL
The sound power and its associated levels are not measurable quantities, but they are calculated, inter alia, from thesound pressure . The sound source itself generates changes in air pressure in their environment perceived by the human ear as sound. Here the sound pressure is (in contrast to the sound power) depends strongly on the distance to the sound source and the respective spatial environment.
SPL
Similar to the sound power, it makes sense, the sound pressure in the form of a level indicate (based on a base value).Here one has to the human hearing threshold agreed as a fundamental value: this is a sound pressure level of 2 / 10,000 μbar (microbars). The sound pressure level there is always the ratio of the actual sound pressure at this basic value (closer to the definition can be found again in Wikipedia (link is external)).
Also the sound pressure level indicated the letter "A" in "dB (A)" indicates that the level an "a-level" (see the explanation for this under sound power level ). However, one should bear in mind: although both sizes have (sound power level and sound pressure level) the same statement "dB (A)", they refer to completely different basic values. That's why sometimes you find the sound power level so the additional "re 1PW".
At this " doubling rule " can be seen that a seemingly small increase in the pressure level (approximately 60 dB to 70 dB) an enormous increase in perceived volume brings with it!
Examples of sound pressure level
From the above considerations we know that a sound pressure level of 0 dB of human hearing corresponds: From this level we can perceive sound. But what typical noise equivalent ? A level of 20 dB or 80 dB
So you this level ranges about some everyday sounds can assign, there are tables such as the following:
From a sound pressure level of 120 dB can already slight hearing loss occur, so here is a hearing protectionrecommended. Vacuum cleaners this is fortunately no longer necessary, but when working with chain saws or jackhammers about Hearing protection is strongly recommended.
| decibel | comparison |
|---|---|
| 0 | auditory threshold |
| 10 | just audible sound |
| 15-20 | lightweight Blätterrauschen |
| 20 - 30 | quiet room |
| 30 - 40 | quiet residential area |
| 40 - 50 | quiet conversation, quiet office |
| 50 - 60 | normal conversation |
| 60-70 | Bus, 10m away |
| To 70 - 80 | heavy traffic |
| 80-85 | Shout |
| 80-90 | Truck, lawn mower at 10m |
| 90-100 | Jackhammer at 10m |
| 100-110 | Jet, Eilzug |