How to choose the audio system? A strip of the reproduced frequencies.
What is the audio system? It is so accepted to call “ in the people “ everything that plays music and is not located in a pocket of jeans. From trivial “ " herrings; with two loudspeakers at the edges of the case, intended for playing of cartridges archaic today to the modern omnivorous hill equipped with ten variegated columns and losing in literal sense “ everything on what write down a sound “.
The main characteristics of sound devices are known. It is a strip of the reproduced frequencies, or frequency range, output power and coefficient of nonlinear distortions. You can not look for values of the last in characteristics. For household devices it is usually not specified therefore we will not consider it, we consider that “ with it everything is normal “.
A strip of the reproduced frequencies - important parameter, will surely specify its value in documentation of high-quality devices of dear brands. It is considered that the ear of the person perceives sound vibrations in the range from 20 hertz to 20 kilohertzes. But the signal with a frequency of 20 kilohertzes will hear not everyone. All of us have features of hearing, and on supervision of physicians after semicentennial anniversary very few people from us are capable to hear sounds with a frequency over 12 kilohertzes.
As show researches, for a speech transmission frequencies from 300 hertz to 3,4 kilohertzes have the greatest information value. But for listening of music of such range it is obviously not enough.
Practical values of the upper bound fluctuate from 12,5 kilohertzes that occurred not so seldom among the devices reproducing cassette records to 24 kilohertzes at very high quality devices. The last case really for gourmets and the rare lucky possessing anatomic ability to estimate existence of such high-frequency components.
It is also necessary to note that physical abilities - not the only restriction which should be considered. The listened music still has to “ to include “ such extreme values. For example, records on the cartridge with a magnetic film of the best quality do not may contain signals with a frequency over 16,5 kilohertzes in any way.
Music records are capable to transfer all nuances of music to DVD. More precisely, transfer these nuances better than other digital carriers. On a disk relatively there is a lot of place, and the size of the musical file - not the most critical size. Therefore record in the DVD format worsens quality of sounding in the minimum degree in comparison with others “ household “ digital formats.
And here the popular mp3 of the exacting listener will not please. The matter is that the compression methods limiting values of parameters of a sound, first of all, of the upper bound of frequency range are applied to reduction of the size of the file. The bitrate is higher, the it is less than losses more than the size of the received file. For example, for bitrate of 128 Kbps boundary frequency usually makes only 16 KHZ.
In spite of the fact that the lower bound of the sound frequencies perceived by a human ear is limited to 20 hertz, the person “ feels “ and lower sounds, or infrasound. The perception occurs all over. Remember how low-frequency basses in discos influence you.
What practical conclusions ?
1. Choosing the audio system, consider that high characteristics are not always necessary also attempt to choose “ the most abrupt “ can increase expenses without the slightest grounds.
2. The frequency range of 20 hertz - 20 kilohertzes will suit almost any judge of music. With rare exception.
3. Not the most expensive device with restriction of the top value of frequency of the range of 16 kilohertzes quite will be suitable for playing only of records in the MP3 format.
4. Value of the lower bound of range of frequencies has to be as it is possible smaller that will allow to lose low-frequency signals in the best way.
Choose, listen and enjoy.]