What acoustics do we live in
The sound of even the most beautiful branded dynamic heads (speakers) without a case, as well as the measured technical characteristics, is absolutely not impressive … But this circumstance can only be bewildering for beginners. We all understand well that a speaker without a box is just like a string without a guitar. The role of this box is so great that they gave it their serious name – acoustic design. And only a harmonious combination of good heads with a well-built acoustic design as a result ensures a decent sound quality of the speaker system (AC). This inevitably leads to the thought of a significant influence on the sound properties of the room itself, in which the music is played.
Rooms, rooms and rooms of various sizes – our housing – turn out to be full participants in the performance of your favorite pieces of music. In the technical descriptions of their systems, the developers give the characteristics obtained, as a rule, in a muffled chamber, when there is no room at all,
But what happens to the sound in an ordinary room? Sometimes you can hear the opinion that some rooms are able to change the sound so much that at the time to raise the question of the appropriateness of purchasing expensive equipment, because all the same, nothing will remain of the “high fidelity” of sound in these conditions … Despite a certain one-sidedness and primitivism of such reasoning , I note that in these words, unfortunately, there is more truth than we would like. But one should not rush to abandon sound systems, because a sensible attitude to the acoustic design of the listening room can not only negate the harmful effects of this peculiar “musical” instrument (closed volume of the room), but even correct the sound of your speakers in some ways.
Volume playing by itself
The air in the room can be fresh, cool, warm or cold, but it is always elastic: remember how this substance imperceptible in everyday life springs when using a hand pump? And since there is elasticity, that is, there is the possibility of “swaying” pressure (scientifically – resonance), when oscillations with a certain period begin to increase so much that they become noticeable by ear! These air vibrations in the enclosed volume of the room “harm” the final sound, because the voice of a typical living room, of course, is not angelic, but low, bass. Pay attention to the pleasure with which your room “sings along” with the growling and rumbling trucks that drive near the house. What happens in a room with speakers turned on? It turns out the same thing – the room often begins to resonate at frequencies that have a noticeable value for hearing, for example, in the range of 20-100 Hertz. For the curious, we’ll reveal a secret: a sound storm arises from the so-called standing waves. A standing wave does not run anywhere and is formed, for example, near a wall that completely reflects sound waves. The length, width, and height of your room set well-defined vibration frequencies. These selected frequencies at which the surf is generated from standing waves are called resonant. They are distinguished by seniority: first, second, third
Moreover, the first – the lowest in frequency – in a rectangular room corresponds to the largest size. When the speaker system is in a room where there is no sound absorption, such a wave will swell smugly and unlimitedly, distorting the music, primarily on the bass. We discussed only, so to speak, one dimension of the room; similar considerations can be made for the other two. But even this does not take into account the complexity of the real picture. Now we can confidently say that in an echoing room with good reflection, not all frequencies of the sound spectrum receive an undistorted display. If the spectrum of the sound signal was smooth in the “deaf” room, then in the room with reflections it will be greatly changed. Some frequencies will receive undesirable amplification, and some, on the contrary, will be blocked. I note that taking into account the resonant properties of the premises is relevant for small volumes, which correspond to typical small-sized apartments. The larger the room, the lower the first resonant frequencies. Thus, the accuracy of the reproduction of the bass part of musical works directly depends on the size of the room.
For a room volume of 35 cubic meters (2.5×3.5×4.5 m), a significant change in sound will take place in the range of approximately 20-200 Hz. The first useful conclusion that can be drawn from the above concerns the geometry of the room. So, if you have the opportunity to listen to music in a rectangular room, then let it be larger and, preferably, its length, width and height noticeably differ from each other, and it is better not an integer number of times. The most unfavorable conditions for listening are created in cubic volumes, here the spectrum of natural frequencies is very rarefied, and bass distortions will have a deep and large-scale character.