ACOUSTIC SYSTEMS

on 24 August 2012.

There is an interesting phenomenon, definitely fixed, but still nevoproizvodimye or played so hard and in such small quantities that large-scale experiments terminated for lack of appropriate conditions. (Give me a lever and I will move the earth!).

There are also commonly used effects and devices widely settled in a region that can be taken on board in a completely different field. But do not take because nobody would never nail microscope ...

These phenomena, give it a term - it does not mean to understand and use it.

In acoustics, sonar, and there are many most unusual devices, and a variety of effects, though the explanation, but not used.

It is known, for example, that whales can communicate at distances of hundreds of miles. This happens most likely when the layers of water of different salinity and temperature to create a channel-sound guide through which sound travels with very little attenuation. Many assumptions, but what exactly is established that sperm whales and communication at distances of a thousand miles, no submarine has today devices that allow it to be linked to the base by means of sonar at these distances.


Measuring blood pressure, the doctor applies to the place where the vessel is clamped, a cup stethoscope. A rubber tube-The sound signal reaches the ears and blind thrusts of blood that would never have been heard even in silence, become distinct and definable. In the early days of medicine, physicians used for such purposes a wooden tube with extensions at the ends (listen to the lungs, heart, and the fruit of God knows what - is medical purposes). Prisoners used for several other purposes circles: they are applied to the wall at one end and the other to his ear. That is, any sound guide, any device that limits the interaction of the wave with the environment, dramatically in the tens and hundreds of times reduces the damping.

Not once, not twice, we met in the literature the phrase "wind suddenly came the sound (voice, shot, talk) ..." And we read phrases like: ... "Do not talk in the evening over the water, the sound goes away ..."

One can assume that the flow of wind is the carrier of sound vibrations. Yes that sound - and the stars twinkles for the terrestrial observer, the stars do not twinkle just outside the atmosphere. That is, a vortex, a jet, a rush, a layer of air is a waveguide (or reflector) sound waves to pass a signal from one point to another as can not be explained from the point of view of classical physics: calm, isotropic in all directions of the atmosphere.

There are several events to which I recommend to pay attention to those involved in acoustics.

The speed of sound in a medium - size known, calculated, otnablyudaema in millions of experiments, depending on the temperature, pressure and frequency are known.

The speed of sound in a moving uniformly and consistently (without vortices only means!) Environment is the speed of sound in a medium. Clearly, the speed of sound in the car will be for given values ​​of the atmosphere and the frequency is the same as without traffic. But for an observer on the platform of the speed of sound increases the speed of the car! That is, if a certain amount of air moving in the atmosphere, and it excited sound waves, in relation to the surface speed of the oscillations will be the sum of the speed of sound in a stationary source and the speed of the volume in which the excited oscillations.

This means that to create a supersonic wave, even without special devices can be, if a moving wave of condensation plant another wave, preferably many times the first frequency.

Explain. Suppose we have created one complete vibration (harmonic movement back and forth of the membrane). Let the velocity of propagation of this wave is 300 m / s. This compression wave. Suppose that at some (not start!) Another point in the process of condensation radiator, located on the same axis as the first emits a high-frequency wave (or a single signal), which is moving uniformly in the bunch is the propagation velocity equal to the speed of sound as well. Then it is logical to expect that this bunch will have a second signal velocity of the speed of sound with respect to a fixed environment (speed of the wave speed of the bunch in the bunch).

Technically, it may look like placing different frequency emitters on the axis of propagation. Since the dimensions of the radiators for different frequencies are different, the basic screening of the radiation (the fundamental frequency of the carrier is usually low frequency) transmitter is negligible.

The speed of sound in a turbulent environment, moving - the process is so complex that it is virtually impossible to transfer. We can only analyze the rare successful discoveries in the form, construction materials, surface treatment ... Create a good violin is an art, not production.

Known turbine (jet) of Laval. It allows you to make a supersonic gas flow rate. In the opinion of the author - this is a godsend. Assume, predict, estimate previously a nozzle is impossible. Of course, there is now convincing calculations, formulas, and that this should be so, and not otherwise, but the emergence of the current in a moving or changing magnetic field has been a godsend, not calculation, and find that the professor did not, and the Faraday able to see something great where others saw nothing.

So, if the narrow channel of distribution of gas, its speed will increase, but only up to a certain limit. When you approach the speed of sound propagation velocity of the gas stream stops growing, but growing resistance nozzle. But if you do, after a section of the nozzle extension, the speed of the jet suddenly increases and the sound barrier. Sound - is also the movement of particles, longitudinal compression wave is moving particles. The amount of displacement of the particles is equal to half the wavelength. That is, for a 300 Hz signal and a speed of 300 m / s displacement will reach 0.5 meters! If the nozzle attachment on the speaker will have comparable dimensions, the particles are displaced will be like a jet of gas phase acceleration, compression, and going beyond the sound barrier.

But it should happen one more interesting phenomenon (or rather, can occur under certain conditions, which will determine the shape and length of the pipe-nozzle frequency). Lord Kelvin once proposed a "vortex machine." It was a tube, one end of which was closed with rubber, and the other is open. Upon impact, the rubber broke loose from the chimney is not a jet, and a ring (torus) of air. If the pipe is filled with smoke, the visual effects were so striking that many prominent scientists have been studying these vortices (Helmholtz in Berlin, Wood in America.) It was found that the vortex is not flying the speed of sound, but much more slowly. Impact of this vortex was so strong that it overturned boxes at distances of tens of meters, Shock ring in man's face was seen as a push soft down pillows. The layers of the torus rotating at high speed, but if you push the two vortices, they do not vzaimounichtozhalis and repel each other, as some elastic material formations. Now these are called solitons, vortices, and as before, and now there is the theory that all material particles are solitons.

We are interested in what these vortices to travel large distances, very little fading, and their influence is so significant that it can not be reduced to the propagation of sound waves. Stroke, for example, the drum passed through the speaker system that generates a vortex ring, apprehended by those who will be on the path of the soliton as a powerful impetus, but in other areas people do not experience its impact.

So, entertainment events require the organizers and producers of highly influencing factors. Increasing the power of acoustic devices is almost impossible and unnecessary - the volume went up to the pain threshold.

The author offers several ways in which, in his opinion, the quality will improve the emotional impact on the audience. Quick again.

Speakers can be fitted with fans. The flow of air from the fans will reflect sound and conducting shell (sound guide), and it will at the same power level than otherwise pass it on without attenuation or distortion.

High-frequency transducers can be aligned with the bass. This should lead to some very unexpected and beautiful effect. Shift some of the signals through the sound barrier with respect to a stationary observer can be accompanied by a decrease of attenuation of high-frequency oscillations, which are podsazheny for low-frequency waves.

Part of radiators can be fitted with attachments, repeating the Laval nozzle. Solitons will radiate a very strong emotional and physical impact.

The introduction of the smoke in, radiating solitons will visually track the path of the soliton, which will further strengthen the emotional impact. See flying vortex ring formed (or appropriate) drum beat or a good finale, to be on his way, and expect to get an elastic soft strike - no doubt it will delight the most indifferent spectator. Visualizing Music with durable elastic vortices, like color music, it's a completely new direction, psychological effects should be stunning.

In addition, the soliton as a dynamic stable system can store a sound.

Imagine that the speaker is in a box with one hole Kelvin. On the back of the (rubber, for example) are applied regular beats. Rings (solitons) with frozen into them sounds emitted in the direction of the viewer. Hit in the audience noted not only the elastic impact, but also a surge of sound effects.

Movement or rotation of the device (speaker) will be accompanied by bursts of sound, the frequency of the sound according to the Doppler effect will increase when approaching and decrease with distance from the observer (listener). Rotary transducer, for example, on the site, the incident on the listener, the frequency will increase, and the moving away-fall. Therefore expand the sound spectrum, there will be new and unexpected effects, unusual sound, a new impact on the listener. And if we add the ability to quickly change the speed of rotation, the effect will be very impressive.

Such devices may be in addition to already apply the speakers, hubs attention rides.

Generators vortex rings might not be related to the speakers that reproduce music, they can be filled with colored smokes, have a different caliber, be directed in different directions, to generate solitons with different frequencies.

And, perhaps, any idiot put in generator Gemgoltsa couples gasoline fumes  and ignite them to the exit? Beautifully will only at long range - in the stadium and is intended up. And if in the face of a potential enemy? Or by mosquitoes and gnats?