Acoustics of Rooms for Listening Music
At first glance, a room for listening to music (RLM) is not much different from a home theater hall. Both here and there, phonogram is recorded on a carrier; both here and there, we have high-quality sound amplification systems. In both cases, the number of viewers/listeners is limited to a few people. However, the difference between these rooms is huge, if you figure out WHAT and HOW they listen.
Ideally, a listening room is an acoustic model of a multipurpose concert hall. Today, a jazz band played in it; yesterday, pianists, and tomorrow, an evening of symphonic music. Passion for different music styles and types is commendable to a listener. However, for the same listening room, a correct reproduction of the sound of different styles is one of the most difficult tasks of small room acoustics. A room that is perfectly tuned to jazz music may sound worse when playing classical music, and it can be completely unacceptable for a rock concert.
Unlike multi-channel sound in cinemas, a listening room uses two-channel sound reproduction systems (stereo). Only left and right channels. Therefore, a sense of a "hall", a surrounding sound, a panorama and the depth of a stage are created through their joint effect with the enclosing surfaces of the room: ceiling, wall sections, floor, etc.
Of great importance is the location of the speakers themselves as well as the location of the listeners in the room. In the process of adjusting the sound, a 100-mm difference in the position of the speakers can significantly change the panorama of the scene. For example, a double bass in jazz composition can move from one place to another on an imaginary stage, which may be completely unnatural for a live arrangement of performers at a real concert.
As in a home cinema, sound absorption in the low-frequency region must be performed in an RLM. In accordance with the laws of physics, there are always problems with the frequency unevenness of the sound field in the region below 200 Hz in small rooms. Thus, without special measures, an RLM will never be like a large or even medium-sized concert hall in terms of the phonogram sounding at low frequencies.
In addition, if home theaters and exclusive products, good listening rooms are definitely works of art. Their arrangement is the result of the well-coordinated work of a tandem: the customer/listener and an acoustic engineer. The first has an exact understanding of what he wants to hear; the second, based on the laws of physics and his personal experience, helps to put this into practice. In a properly arranged listening room, everything must be balanced: a high-quality equipment, a suitable room in terms of its size, a right acoustic design of this room. Otherwise, the owner of expensive equipment will never hear its benefits.
When designing listening rooms, the following principles should be observed:
- The shape and proportions of an RLM should be selected on the basis of the physical principles of sound propagation in confined spaces.
- For each specific room, an LF absorber system is developed, which creates a uniform field in the low-frequency range.
- The reverberation time in the room must be within the range recommended for listening rooms (for example, Trev = 0.4 sec).
- The interior of the room should contain a uniform alternation of sound-absorbing and scattering surfaces. It is allowed to place scattering or reflective surfaces in the areas of the first reflections.
- Any acoustic defects must be excluded in the hall, such as "fluttering" or "theatrical" echo, caused by using parallel sound-reflecting surfaces and reflective surfaces of a large area at large distances from speakers.
- The interior decoration of the audience hall shall use environmentally friendly materials, suitable for long-term use, having known and stable acoustic characteristics.
As decorative acoustic materials, the construction of listening rooms uses Decoustic panels, SOUNDBOARD Fine and SuperFine panels, Ecophon Akusto wall panels, Ecophon suspended ceilings as well as Gyptone and Rigitone Air wall and ceiling boards. For listening rooms, you can also use FLEXAKUSTIK boards and CARA acoustically transparent fabric.
As internal sound absorbing material, ecologically safe nonflammable Shumanet-ECO boards are used. To prevent rattling of the metal frame, the Vibronet-profile system is used for installation of decorative acoustic materials.