The ideology of creating resonant acoustics

The sensation of sound is a special sensation, incomparable with any other of our sensations. Directly or indirectly, but all issues related to sound should be resolved on the basis of anthropocentric subjective assessments, in particular, by the ear as an organ of hearing. Sounds can be classified into musical and non-musical. The former can be called notes, the latter noises. However, it is not easy to draw a line between these two categories of sounds.

But, although the noises are sometimes not musical, and the notes are not completely free from noise (for example, when several keys of the piano sound some kind of noise), however, no combination of noises could merge into a musical note. It is therefore advisable to pay attention primarily to musical sounds. These sounds are arranged in a certain order, the periods of which are related as mutually inverse prime numbers.

These are all consonant sounds within an octave. You will notice that all relationships between them are expressed in terms of integers.

It should be noted that sounds containing only odd overtones always sound a little empty, even overtones, especially the second and fourth, make the sound light, the seventh and thirteenth are critical and can spoil the sound quality. Ideally, only the first seven overtones should be heard, since the musical intervals are limited to the seventh overtone.

The desire to form the amplitude-frequency characteristics (AFC) of electroacoustic emitters as close as possible to linear ones, observed everywhere in practical designs, inherently does not meet the conditions for optimal coordination with the auditory perception of a person, since it creates equal conditions for reproducing both a signal carrying useful information and for parasitic noise signal.

Resonant Acoustics forms a natural acoustic picture like natural sources of sound and musical instruments, creating a volumetric acoustic effect adequate to optimal psychophysiological perception.

Physical prerequisites for the construction of resonant acoustics

• radiation of a re-reflected sound signal;
• resonant excitation of the sound field by forming a set of standing waves, the vibration frequencies of which are related to each other according to the law of a natural musical row;
• forced formation of a special comb amplitude-frequency characteristic of a secondary sound source – resonant acoustics adequate to the spectrum of the primary sound signal in resonant acoustics comb-shaped frequency response is created without using any electronic filters.

In this case, the local maxima of the frequency response correspond to the frequencies that form a natural sound row, and the local minima lie between them. This provides amplification of the consonant components of the audio signal and suppression of dissonant ones; creation of a sound field with a spheroidal directivity pattern, which has all the properties of the field of an ideal sound source – “Pulsating Sphere”, which allows the listener to relieve the listener from spatial dependence with high-quality sound perception, due to the diffuseness of the sound field.

Direction of Sound Ecology

Leading physiologists at St. Petersburg University have identified a positive effect of reproducible resonant acousticssound on the human body. Listening to various pieces of music through resonant speakers has a significant positive effect on the psychophysiological state of a person.

For a comparative assessment of the impact of various acoustic systems three techniques were used:

• Electroencephalography (EEG)
• Digaplascopic measurements of brain lability
• Variation heart rate monitoring

The research involved 36 people with different types of the nervous system, different physiological lability of the brain, different types of perception of musical programs, age differences. In the experiments, musical fragments sounded from 10 minutes to 2 hours. Each experiment used music of a different style (classical, pop, meditative).

As a result of research on the impact resonant acoustics in comparison with traditional acoustic systems, the following was revealed:

• An increase in the alpha rhythm (characterizes the protection of the brain from stress and the restoration of neuropsychic functions) by 46% in all areas of the cerebral cortex;
• Increase in the coefficient of bilateral (interhemispheric) asymmetry (dominance of the left hemisphere – “clear consciousness” mode, or “operational rest” mode) by 12%;
• Increase in the coefficient of the frontal-occipital gradient of activation (activation of the state of mental composure, reflecting the dominance of social motives) by 17%;
• Strengthening functional lability to the pulses of red light (increasing the capacity of the brain, eliminating overwork);
• Decreased heart rate (calming, reducing psycho-emotional overstrain);
• Decrease in the number of functional extrasystoles (decrease in heart rate interruptions of a neurotic nature);
• An increase in the number of compensatory pauses (additional rest of the heart);
• Decrease in dispersion of interpulse intervals (normalization of heart function).

Listening to music using resonant acoustics leads to a significant improvement in the neuropsychic state of a person.

Thus, resonant acoustics which does not cause fatigue, and also contributes to the strengthening of the restorative and protective functions of the body, is the first step in a new direction in acoustics – Sound ecology. Main technical characteristics:

Maximum sound pressure level, dB	103
Maximum long-term power, W	100
Nominal resistance, Ohm	eight
Frequency response, Hz	45-20000
Horizontal Beam Width	± 180 °

Literature:

1. USSR author’s certificate N 936462. class. H 04S 5/00. 1979.
2. Inventor and innovator. No. 6, 1983, pp. 16-17.
3. Vakhitov Ya.Sh. Theoretical foundations of electroacoustics and electroacoustic equipment, M., “Art”, 1982
4. Strett J.W. (Lord Rayleigh) Theory of sound, ML, Gos. Ed. Technical and theoretical literature, 1940
5. Skuchik E. Fundamentals of Acoustics, M, “Foreign Literature” 1958