This story, like many others that appeared on the pages of Android Insider.ru, began when my friend approached me and asked if it was possible to measure noise using a smartphone. Well, to be accurate and in decibels, he said. Without thinking twice, I gave an affirmative answer, because smartphones have a microphone, which means that they can measure noise. Therefore, I took and sent a friend to Google Play for the appropriate application, giving accompanying instructions that the software should be selected with an eye to the average rating and reviews of other users. But I was wrong. In everything.
You can measure the noise level with a smartphone, but in general it is not necessary
Almost immediately after these instructions, I asked my comrade what exactly he was going to measure. No, then I had no thoughts about my own mistake, and the question was asked out of idle interest. He replied something about the noisy refrigerator that is heard throughout the apartment, and we happily said goodbye. However – I myself do not know why – the thought of measuring the noise did not leave me even after. Therefore, pretty soon I found myself studying sites about sound, methods of measuring it and so on. I share the squeeze with you.
How to measure noise from a smartphone
A smartphone, with all its desire, cannot play the role of a sound level meter
When measuring noise, a technique is of great importance, which must be followed rigorously in order for the result to be correct. Therefore, the fact that applications can measure noise in decibels does not mean that the measurements are correct. And it will be simply impossible to comply with all measurement requirements at home.
I think you know, or at least have heard, that measurements are usually carried out using a special apparatus called a sound level meter. This is a small device the size of a smartphone, which has a microphone on one side, placed outside the body on a small bow. This achieves a directional effect that allows you to record sound emanating from a specific area. In addition, this same microphone is always wrapped in a porous material that acts as a cut-off. It is needed in order to cut off sharpness. A smartphone doesn't have that.
What you need to measure noise
However, the surprises don't end there. The distance from which the measurement is made is of great importance. If you want to measure the noise of the refrigerator, like my friend, keep in mind that at the factory or in service centers, when the noise level is measured, they do it from a strictly defined distance, not to mention special conditions, which will be discussed below. Without knowing these subtleties, you run the risk of getting a completely erroneous result, even if you manage to put a piece of foam rubber on the microphone of your smartphone to imitate the cut-off function. It is quite easy to verify this. Download a suitable app and measure your voice volume twice. The first time, bring the microphone close to your mouth, and the second time, place it at arm's length. I assure you, the results will be dramatically different.
Well, and, of course, do not forget about the measurement conditions. Sound, like gas, tends to spread throughout the room, and the larger it is, the less its concentration is. Therefore, if you try to take measurements in a cramped kitchen and in a huge gym, the readings will differ. To prevent this from happening, firstly, a room of the appropriate area is selected, which is usually not disclosed to ordinary users, and, secondly, the entire room is upholstered with foam rubber to isolate it from external noise. For the same reason, measurements are taken in rooms without windows, from which outside noise can also pass.
Should you buy noise measurement apps
This begs some conclusion, doesn't it? In principle, you can indulge in measuring noise using a smartphone, however, in order to get an accurate result, in order to use the obtained readings in the future, you probably will not have enough mobile phone. For the same reason, we strongly advise against buying paid noise measurement applications that promise that they can be used to make all measurements even in a village barn. After all, there will be no sense from this anyway.