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Acoustic systems C2. Electrodynamic heads with flat diaphragms Flat "Touch" speakers for mobile phones made by Matsushita Electronic

Installing rear speakers of ordinary sizes

The rear speakers deliver a lot of "headaches" to the owners. If they are put on original or not branded stands, they begin to interfere with the free passage to the sofa, often injure the owners with sharp corners of the housings, cables from them interfere with their feet. The center of mass duet column-support turns out to be located above that the stability clearly does not add. Fucking supports for rear acoustics are very rare and even less often fall asleep with sand or fraction.

With the suspension of traditional rear speakers, there are also difficulties. If the columns on the wall brackets, the resulting depth of such a design turns out to be around 30 - 40 centimeters, they simply "stick out" and their views clearly do not decorate.

In order not to touch the tail of the speakers, they are suspended at an altitude of 1.7 - 2.0 meters from the floor level. The columns on the wall fixed by the brackets are much higher than the frontal acustic systems And the resulting sound picture rear is "handled". Required by the director 3-D sound effects are distorted.

HECO MUSIC STYLE REAR 200 F flat acoustics and its advantages

Flat wall acoustics not so long ago appeared in model ranks Heco, closes a lot of technological and aesthetic issues.

Flat acoustics does not spoil the interior at all and looks rather not an acoustic system, but a certain furniture element. Strengthened close to the wall, it is the protrusion Minimum distance of 10 - 11 cm, it is almost impossible to hurt it.

Mounted at the height of the ears of the seated person (110 - 150 cm. From the floor level) Flat wall acoustics Heco Music Style Rear 200 F Together with the front speakers, it creates a perfectly smooth sound picture in a horizontal plane.

Hanging the minimally protruding speakers on the wall Even in an amount of 4 to 6 pieces, you can create a full-fledged home cinema with 7-9 rear channels in the latest Dolby ATMOS or Auro-3D surround sound formats. At the same time, this multiscolone audio system will not cause any damage to the interior.

The second area of \u200b\u200bapplication of the speakers on the wall is to pick up a high-quality audio system of secondary premises in the house: dining rooms, kitchens, children's and bedrooms.

Mounted from two sides from the hanging TV speakers on the HECO Music Style Rear 200 F wall creates an excellent stereo sound picture, do not occupy almost no place and look very organic.

In the dining room, kitchen or children's use of full-size floor columns is often inappropriate, and owners have to listen to the sound of disgusting quality, which comes from the speakers embedded in flat TVs. Forted from two sides from TV high-quality speakers on the wall, work every ten better than internal, even from the relative - television amplifier.

P.S. HECO Music Style Rear 200 F Flat Acoustics This is a high-quality product with a natural, reference transparent in the voice range. By purchasing these rear speakers, you will never regret money spent on them.

While our industry has established the release of electronics 100as, the progress in the West did not stand in place, introduced new speakers with coaxial, isogenic, electrostatic loudspeakers. The largest Japanese corporations are Sony, and then Matsushita (Technics), began to develop brand new dynamic heads operating in piston mode. Main a distinctive feature These speakers were completely flat, rather than cone diffusers of cellular design. The flat radiating surface does not have resonances inherent in cones, there is no voltage zones and by itself phase and closer in nature to musical instruments.

Already in 1978, Sony presented the prototype of the highest-tech speaker system in the world - Sony / Esprit APM-8. The diffusers of all four speakers of the square shape, the low-frequency was as many as 4 cobalt, the core powerful magnetic systems that moved a single flat diffuser, as if the piston. Then there was a deep bass reproducible to a single ac-deep bass in 25 Hz in terms of level - 8DB, and laying a day unattainable small books in a low-frequency area, which even 40Hz does not exceed 2%!

Sony / Esprit.APM-8 (1978)4 bands, the possibility of multipping, housing with an antidifraction coating, 102kg. 500W. 25-30 000Hz.

Inexpensive, but high-quality flat cellular emitterTECHNICS. (Applied to Technics SB-7 model)

Technics.SB-10, isoodinamic HF emitter, cellular sch with "invisible" suspension, cellular lamp (32cm) with coil super-large diameter (160mm). Magnet and two centering washers are inside this coil! It turns out as if the speaker inside out. A similar complex design was produced only by technics and then short time.

The company LO-D (Hitachi Concern) did not follow the path of Sony and Technics and developed its own flat diaphragms, but not a cellular design A with a filling of synthetic foam and velvet acrylic coating of the radiating surface, the same LO-D apertures were used to manufacture passive emitters.

TRIO (Kenwood compartment, a high-end audio engineering) used conical LC emitters reinforced with stiffener cellular ribs. An acoustic design was a special Rupoore Phazoinverter, which occupies the entire back of the speakers. SC / RF TRIO emitters produced with flat diaphragms of carbon fiber, with impregnating acrylic resins.

JVC in its speakers (Victor Zero-7) developed diffusers entirely from the foam-resin composition. In the design of speakers, the suspension was fixed on the reverse side and was "invisible." Innovation was that reflection of sound waves disappeared from the edge of the suspension, which are returned back to the diffuser in the standard design. Supplement three bands of such speakers The ultralight belt superstere with an acoustic lens.

LO-D HS-5000 (LO-D Division Hitachi, specializing in high-end techniques)

Flat emitterLO- D., diffuser filled with special foam and laminated with metal.

Flagship model firm TECHNICS - SB-M. 1 (1981) 4 bands, cellular emitters - a kind of response Sony / Esprit APM-8, only more than twice cheaper .

Cellular filling of the diffuser gives incredible stiffness at the highest internal coefficientdamping, while possesses a low mass.

Trio Ls.-1000, rear panelis a mouthpiece thatinteractroominglistening to what raisesreturn myselflow frequencies.

Onkyo.SCEPTER-300, rear panel with sight of the usual speaker has 6 multidirectional sch-HFemitters that according to the words of the developers, gives a feeling of a complete 3-dimensional picture of the sound image.

VictorZero -7. Thanks to the use of flat emitters, even in a multi-band design, a minimum phase correction is sufficient.

Diatone DS-505, 4 bands, tapered LF diffusers - cellular design, dome - over lightweight titani boron.

At the turn of the 70x-80s, after long experiments and research, many constructors concluded that the perfect emitter is a point source of sound. In such a loudspeaker, phase and transitional distortion are minimized, the sound is radiated from one point without separating bandwidth speakers (LF, SC, HF) in space. What gives the listener to the feeling of complete presence at the concert, the sound is not attached to the AC, and all virtual sources are definitely localized in space. Broadband dynamic heads are not able to reproduce the entire audible frequency range, especially in the high-frequency part. Therefore, the developers began to install several loudspeakers on one axis. Most interesting solutions Apply Tannoy and Altec Lansing.

The Tannoy company used large LC paper speakers with an acoustically transparent dustproof cap and a tapered hole in the core, through which the RF speaker radiated, mounted inside the head of the head of the head and operating from its magnetic field. The main minus of this concept is the oscillation of the highway of the diffuser, which is at the same time with the HR HRP.

Tannoy Autograph (K3808) (1979) Developed specifically for location in the corner of the room. Acousticdesign - Frontal part of the dynamics are loaded onto the root, the back of the sophisticated labyrinthforms.

Coaxial speakerTannoy. The domestic RF emitter is inside the conical LF head and uses its magnetic field only on the other side of the magnetic system.

Altec Lansing 620B Monitor, 1978 RF driver attached from behind a large 15 "LF dynamics and radiates through a hole inhis cace on his own mouthpiece.

And only by the end of the 1980s, Technics managed to completely embody the theory of the point emitter in its AU of the SB-RX series. In addition, the TECHNICS point emitter worked in the piston mode and was absolutely flat.

I wanted to note another significant idea of \u200b\u200bthe 190s and 1980s. This is a reverse mechanical communication system (EMOS) developed by Philips. Everyone knows that the amplifiers with a high output resistance are very lively and naturally transmit the sch and the RF spectrum of a musical signal, and low-out-resistance amplifiers (which causes a high damper factor), well, and accurately play the bass. Philips engineers have placed the micro sensor heads on the Diffuser, which monitors amplitude, temperature, power and other parameters. Then the data is sent to the microprocessor, which controls the amplifier installed in the AU housing. Based on the information received, the microprocessor adjusts the output resistance of the amplifier. When implementing multi-band gain, the design is exempt from passive crossovers in which part of the signal is lost. The ability to change the amplifier parameters, as it is necessary in this moment time.

The development of loudspeaker heads with flat cellular diaphragms began in the 80s, but it became relatively recently to produce the AC with their use. Last year, our magazine has repeatedly introduced radio amateries with acoustic systems of various classes on the basis of cellular heads whose production is engaged in the St. Petersburg Firm "Sound". This information interested in many readers who were asked to tell about the advantages of such heads, bring parameters. Going towards their wishes, we publish the article by the former workers of the VNIIRP them. A. S. Popova, engaged in the development of heads with cellular diaphragms.

It is known that many factors affect the quality of sounding AUs, but, first of all, it depends on the loudspeaker heads used in them. Given these circumstances, electroacustic specialists close attention pay not only to improve the designs of mobile head systems, but also on materials of radiating elements.

As a result, in recent years, along with traditional conical diffusers, widespread heads with flat diaphragms were widely used.

The basic requirements for the physico-mechanical parameters of the materials of the radiating elements are, as is known, high rigidity on bending, low density and large internal losses. The higher the first of the named parameters, the wider the frequency range of the head and the amplitude-frequency distortion is less in the signal.

The density of the material of the radiating element largely determines the sensitivity of the head and, finally, the internal losses contribute to damping the oscillations on the resonant frequencies.

For decades for the manufacture of conical diffusers of dynamic heads, a paper mass was used mainly. With the development of Hi-Fi techniques, leading manufacturers of high-quality speakers in order to increase the elastic modulus and loss of diffusers of heads began to apply all sorts of composite materials based on cellulose (for example, cellulose with coal or metal fibers).

However, it was not possible to significantly increase the rigidity of such materials due to the small internal elastic forces that bind components.

For this reason, for the manufacture of emitters of LF, SC, RF heads of high-quality speakers began to use polymer materials such as Malar, polyamide, polypropylene, polyvinyl chloride, olefin films, tergal, suprepare, ceramic olefin, polymer graphite, etc. no less widely used For these purposes, composite (becters, hobex, cappton), as well as layered Malar and polyester layered materials with aluminum spraying, two-layer polypropylene).

The development of chemical vacuum deposition technology has also made it possible to obtain a number of layered metals (titan-carbide boron, aluminum-magnesium, aluminum-sapphire, etc.). For dome-shaped diaphragms, the sch and RF heads are used simply metals: aluminum, titanium, beryllium alloys, porous nickel.

Table. 1. Main specifications Flat diaphragm heads

Main technical characteristics	300GDN-1.	200Jdn	100GDN	25GDN	75GDS	50GDS	10GDV-5.	25GDSh-2M.
The level of characteristic sensitivity, dB / W / m	90	88	87	87	92	89	91	87
Nominal frequency range, Hz	20..3150	31,5..4000	63..5000	70..6300	200..6300	250..6300	2000..31500	80..16000
Nominal electrical resistance, Oh.	4/8	8	8	4	4/8	8	8	4/8
Maximum noise (long-term) power, W	200 (300)	100 (200)	75 (100)	25 (50)	50 (75)	25 (50)	20	25 (50)
Gabarites, mm.	315*130	250*120	200*90	125*65	160*85	125*65	11011035	125*65

However, the production of many of the materials listed above requires very complex and expensive technological processes. In addition, they are not versatile, that is, they cannot be pressed for the manufacture of radiating items of all parts of the AC (LF, SC and RF heads).

For this reason, the head with the radiating elements of the materials listed above was not able to replace the heads with paper cone diffusers and until recently remains only separate successful achievements of leading foreign firms.

Analysis of the properties of materials of emitting elements and directions for constructing speakers for speakers for hi-Fi class Specialists of the VNIIRP them were constantly engaged. A. S. Popova. The results of fundamental studies conducted by them in 1980-1990. Showed that a very interesting and promising direction of designing dynamic speaker heads is the use of flat cellular diaphragms as a radiating element.

One of the main advantages of this direction is the suitability of such a diaphragm for the design of the NCH, SC, HF and even broadband speaker heads, as well as the ability to create acoustic systems of all destinations, from automobiles to the AS class Hi-Fi and High End.

It is known that a flat cellular diaphragm has a three-layer design: the basis in the form of bee honeycomb from aluminum foil, covered on both sides with shelves from sheet materials.

Three-layer materials based on cellular aggregate have been used for many years in the aviation industry. However, the specifics of the loudspeaker heads demanded the creation of new technological processes and special equipment for the production of cellular diaphragms.

Many years of experience in designing heads with flat cellular diaphragms made it possible to identify a number of their advantages over traditional heads with paper diffusers.

First of all, the heads with cellular diaphragms reproduce a wider range of frequencies with minimal amplitude-frequency distortions of the sound signal, which allows you to create an AC based on them with non-uniformity response in the operating range of +1.5 dB. The use of cellular diaphragms makes it possible to significantly reduce and nonlinear distortion.

On their base, you can create more powerful heads of loudspeakers, because heat from the sound coils is dissipated in them through the diaphragm into the surrounding space, while in the heads with paper diffusers through the parts of the magnetic pipeline it enters the inside the AC.

The flat surface of cellular emitters does not require adopting special measures to align radiation centers, which significantly simplifies the design of the AC.

The electro-acoustic parameters of the cellular heads are less susceptible to the influence of temperature and humidity, are more stable under serial production.

Currently, the company "Sound" has developed a line of cellular dynamic heads of loudspeakers. Their basic specifications are shown in the table. Appearance One of the heads (100GDN) is shown in the figure. On the basis of the heads presented in the table, a series of speakers ("Lira", "Neva", "Rus") are produced, with which readers are already familiar.

Literature:

Demidov O. F., Romanova T. P. Analysis of modern materials and areas of constructing foreign heads of loudspeakers with dome-shaped diaphragms, "Communication equipment", Ser. TRPA, 1979, vol. 3.
Belogorodsky B. A., Kingkova T. P. Forced oscillations of dome-shaped diaphragms of loudspeakers, "Communication equipment", Ser. TRP, 1976, vol. one.
Romanova T. P., Polyakova I. B. Calculation of dome-shaped diaphragms of new loudspeaker heads for reproducing medium and high frequencies, "communications equipment", gray. TRPA, 1980, vol. one.
Demidov O. F., Romanova T. P. Development of new loudspeaker heads with dome-shaped diaphragms to reproduce medium and high frequencies, "Communication equipment", ser. TRPA, 1980, vol. one.
"Experience, results, problems." Collection of articles, ed. Valgus, Tallinn, 1985, p. 95-163.
Kingkov A.N., Romanova T. P. Calculation of the design of flat cellular diaphragms with rigidity ribs. Proceedings of the All-Union Scientific and Technical Conference, "Prospects for the development of radio broadcasting techniques, soundsaw and acoustics." Leningrad, 1988.
Kornkov A.N. oscillations of round and square cellular diaphragms with rigidity ribs, "communications equipment", 1990, vol. 2.
Kingkov A.N., Tovstik P. E. Forced oscillations and radiation of sound with a flat cellular diaphragm of the loudspeaker, " Technical acoustics", Volume II, vol. 3, 1993.
Romanova T. P., Tarasov Yu. V. and others. Production of cellular diaphragms for dynamic heads of loudspeakers, "Communication equipment", Ser. TRP, 1990, vol. 2, p. 37-55.

The standard dynamic loudspeaker, which we know today, was developed in the 1920s and uses a magnetic field to move the coil or magnet, which is connected to the diaphragm. Of course there are other types of speakers that depend on the type of enhancing devices, in addition to standard round speakers, in this article we will look at a bit of the main types: Rupor (horny), piezoelectric, magnetostriction speakers, electrostatic, tape and flat magnetic columns, wave, flat panel Columns, "air traffic converters", plasma speakers, and digital columns.

1. Rozhkovy (ripped) speakers

These speakers were the most first form to enhance the sound. They do not need electricity to enhance. These speakers were used in their designs for example: Thomas Edison, Magnavox, and Victrola. The period of their use is approximately 1880 to 1920.

The main disadvantage is that they cannot qualitatively powerfully produce. In the future, they will fully displace the speakers and devices based on electricity. Today they are interesting only as an exhibit for collectors, it is true that there are modern developments that fully or partially use the principles of horn speakers.

2. Electrodynamic (modern) speakers

What is an electrodynamic speaker? This is a device that uses an electromagnetic coil and a diaphragm to create sound. This is the most common type of speakers in the modern world.

How it works?

Modern speaker uses electromagnet to convert the electrical signals of different power into the diffuser movement. The coil of copper wire moves in a magnetic field. It works using the principle of induction. The coil is connected to the cone from cardboard, paper, vinyl or other material. The diaphragm cone vibrates together with the electromagnetic coil. The sound is created and enhanced directly the diaphragm itself. The peculiarity of these speakers is that each type of speakers is performed for a specific frequency range, because it depends on the type of magnets, material and purpose of speakers.

A little about sound:

The sound is one of the forms of energy passing through the gas or liquid medium. There are two basic parameters for measuring sound: frequency and volume level (decibel). The frequency is responsible for sound quality in the dynamics, decibels for the volume of sound.

People can hear sound with a frequency from 20 - 20.000 Hz. Hertz is the number of cycles per second. The sound is a wave in the range of energy levels to infinity.

If you look at the music, then any note does not sound at a constant frequency, this is a sound wave that reaches a maximum for notes to diges 1 octave, for example, every 277-278 times per second. Partly spectrum perceived by man (approximately) from 20Hz to 20 KHz,
The greatest sensitivity in the range from 2 to 4 kHz.
Dynamic range (from the most silent perceived sounds to the most high-profile) about 96 dB (more than 1 to 30000 on linear scale).
It is well known that a person is able to distinguish the change in frequency by 0.3% at a frequency of about 1KHz.
If two signals differ in less than 1 DB amplitude - they are difficult. The amplitude resolution depends on the frequency and the greatest sensitivity is observed in the range from 2 to 4 kHz.
Spatial resolution (ability to localize the sound source) - up to 1 degree in humans.
Sounds of different frequencies are distributed in the air with different speed. As a result, the high-frequency part of the spectrum from the source at the removal from the listener is somewhat late.
A person is not able to notice the sudden disappearance of high frequencies, if it does not exceed the order of 2ms.
Some studies show that a person is able to feel the frequency above 20khz. With age, the frequency range is narrowed.

For human speech, the frequency spectrum, carrying information: from 500 Hz to 2 kHz
Low frequencies in our speech are bass and vowels, high frequencies - consonants.
Since the neuron can be excited not more than 500 times per second, for obtaining information on higher frequencies, the person's hearing aid resorts to some "tricks": at frequencies up to 500 Hz - oscillations are directly moving into nerve impulses.
Approximately 1.5kHz The problem is solved by connecting simultaneously up to 3 neurons to one nervous end. Neurons in this case are excited sequentially, one by one and, accordingly, helps to improve frequency resolution 3 times.
At higher frequencies, only the amplitude of the signal is recorded.
Thus binaural The hearing that plays a large role in the localization of the sound source is best developed at the frequencies of the smaller 1.5kHz. Above this frequency, the source of location information is only the difference of signal amplitudes for the left and right ear.

The main stages of the development of modern speakers:

1861 - The easiest type of electronic speakers was developed by Johann Philipp Reis - Teacher in the city of Friedrichsdorf, Germany. The speaker was capable of rudely very "roughly" to reproduce the sound. It was the first experience of using an electrodynamic loudspeaker.

1876 \u200b\u200b- Alexander Graham Bell also makes experiments with the creation of a dynamics based on the work of the flight.

1877 - The idea of \u200b\u200ban electromagnetic coil for use in the speakers made by the Werner Siemens, it used it to convert the input signals of the DC Telegraph. He had no solution to enhance sound, but he suggested that this eventually can be done in the near future.

1877-1921 - Various inventors and engineers work with the idea of \u200b\u200belectrodynamic loudspeakers, but still it turns out to create only coarse, distorted sounds. Industry continued to release horn speakers.

C.W. Rice from GENERAL ELECTRIC and E.W. Kellogg from AT & T together worked in Schectectadi, New York, over the improvement of electromagnetic speakers and the first electric gain system. They created a working prototype in 1921. Rice and Kellog were able to solve the finally all the problems that led them to good, clear sound. Previous attempts to make the loudspeaker gave bad, unacceptable, muted sound. This muffled sound was not good enough to compete with the sound of a horn speaker, which was well known in the market. Rice and Kellog were able to fully understand what is needed to play all the frequencies required to create an accurate sound. Their prototype has a sufficiently large dynamic frequency range to be better than the range of the horn dynamics, while having to significantly increase the volume. In 1925, they filed patents and spoke with a speech in St. Louis at the AIEE conference ( American Institute of Electrical Engineers). After several years of work, they have improved him as the first commercial product of a kind and called the Radio Loudspeaker No. 104. She was sold in 1926 for $ 250 (about $ 3,000 today). The speaker was sold under the RCA brand.

Electrodynamic loudspeakers are now produced under several tasks and are divided into main categories:

Foods ( Tweeter. ) - 2 kHz - 20 kHz, are used for the production of the entire upper line of high frequencies. Cookies are made according to the principle of electrodynamic loudspeakers, but there are piezoelectric, electrostatic and plasma high-frequency speakers.

The dynamics of the average frequency ( Mid-Range. ) - 300 - 5 kHz. This range covers most of the human voice along with most musical instruments.

Low frequency speaker ( Woofer. ) - for frequencies 40 - 1 kHz.

Subwoofer ( Subwoofer.) - 20 - 200 Hz. Very low frequencies. Human ear can only hear up to 20 Hz. Low Frequency Range. This means that it can be placed anywhere in the room and be heard from any point with the same sound quality. Subwoofers also produce sound waves that penetrate easily through the walls. Noise from this type of speakers may even penetrate vertically after 5 or more floors from concrete in residential buildings. Overly to say, it is easy to get into trouble with local noise regulations. Subwoofers were developed in the 1960s.

3. Flat panel columns

NXT-technology is allocated here.

NXT panels - This is one of the options for the execution of flat-panel loudspeakers. The development was based on the military industry, however, the main use of such devices were found in consumer electronics. Parrot uses this technology in Minikit Slim devices, Minikit Chic and Minikit L.E.

Speaking about the features that distinguish the system, we should be called those that are important when using a device in a limited space:

practically impeccable radiation of sound in all directions;
the low dependence of acoustic pressure when removing the NXT panel. That is, the sound quality does not fall when the user is moved.

Unlike conventional loudspeakers, NXT is the technology of flat panels, where its excitation is carried out from one point using a movable coil, piezoelectric element or other pathogen. The NXT drive maximizes the resonant behavior of the panel, for example, thanks to the choice of the surface material and determining the location of the causative agent.

The basic idea is to obtain the maximum random nature of the movement of any two neighboring points of the surface of the panel relative to each other - and this is the main breakthrough NXT.

In a very rigid panel of the NXT system after an excitation based on the usual electrodynamic or electrostatic principle, complex vibration processes occur on the entire surface. In this case, the resonant properties associated with the structure of the material and the excitation point are becoming more intense, adjacent items of the material begin to arbitrarily vibrate. The scientific name of this phenomenon is "mode of distributed vibration". Try to imagine the highway by the highway, on which the bugs go into deepening and vice versa. It is necessary that the structure of vibrations in the entire frequency range would be as complex and dense as possible.

Unlike conventional multi-band loudspeakers, one NXT panel is used to play the entire audio range, excited using a single transducer. At an area of \u200b\u200b0.6 square meters. M Lower boundary frequency is 100 Hz, and the upper 18 kHz. And the deviations of the frequency response are the same order as in conventional loudspeakers. With increasing area to 1.5 square meters. M Low-frequency border decreases to 60 Hz. NXT panels can operate at 25 square meters. See 100 square meters. M! The smallest can be used in the multimedia system together with a laptop, and the largest in cinemas, serving simultaneously screen. And at the same time, there is a completely boundless sea of \u200b\u200bapplications from automotive acoustics and portable devices (Parrot Minikit Slim) to completely inconspicuous (for the eyes, but not small size) built-in acoustics, imitating even architectural fragments of the room.

NXT panels can operate at 25 square meters. See 100 square meters. M! The smallest can be used in the multimedia system together with a laptop, and the largest in cinemas, serving simultaneously screen. And at the same time, there is a completely boundless sea of \u200b\u200bapplications from automotive acoustics in the form of a shelf under the rear glass to a completely inconspicuous (for the eye, but not small sizes) built-in acoustics, imitating even architectural fragments of the room. Speaking of parameters that have a distinguished system that distinguishes the system must first be called almost impeccable radiation of sound in all directions, the quality of which is slightly reduced at low frequencies compared to classical diffuser loudspeakers. In addition, the dependence of acoustic pressure when removing the NXT panel is significantly less. And if measured by traditional methods sound pressure At a distance of 1 meter, they have 4 dBs less than that of the average dynamic loudspeaker (for which we take 90 dB SPL), then when moving by 3.5 m for NXT, it will decrease only 4 dB against 11 for acoustics with traditional source converters Signal. So, when you move the listener on the room, it is almost impossible to detect any changes in the frequency spectrum, nor volume. During the demonstration, the turn of the panel for 90 ° or the room behind the back of the demonstrated specialist was practically influenced by the quality of playback. Thanks to microscopic movements, the character of the impedance of the pathogen for the panel will be simply resistive, which greatly facilitates the operation of the amplifier.

The NXT system practically does not exist any capacity limitation, although the temperature of the converters still have to control the temperature. On the other hand, the panel themselves simultaneously play the role of the cooler. Moreover, the shape of the panel can be accommodated to the stand on which it will be delivered. At the same time, one should not forget about the energy loss of one side of the panel. The subjective impression on the sound of the NXT system panels can be described as transparent with detailed recognition and transmission of short-term signals without distortion. With regard to Hi-Fi reproduction, then relative disadvantages include some restriction of low frequency bands, as well as the loss of accurate localization. These disadvantages are caused by the so-called "diffuser" of the sound field, which is not the disadvantage itself, and for the rear acoustics of the home theater, the TNH is even necessary, but nevertheless it will be possible to get rid of it in the process of improving the NXT system.

4. Membrane columns

The principle of operation lies in the fact that magnetic fields are used to move the sound-reproducing element (diaphragm). In such a dynamics, the coil is mounted directly on the diaphragm. The main cost of such speakers is a high power, a wide range of reproducible frequencies and compact, especially in thickness, dimensions.

5. Columns based on plasma arc

The plasma is ionized gas, or a current in gas. Plasma responds to electrical fields, so you can turn on the electrical signal (sound) into an electric field that manipulates the plasma. Plasma has a mass and it will vibrate creating sound, it looks like the air moves in a diaphragm to obtain sound. Such speakers are visually quite interesting, but limited as sound. Such developments have problems with reliability and therefore remain only as a concept or devices for lovers.

6. Piezoelectric columns

Piezoelectric speakers are limited in frequency response so they
used only as tweeters (sakes) in small electrical devices, such as the clock to reproduce simple sounds. Such speakers are made on solid-state technology, which makes them very durable, this is an excellent solution for use as a microphone under water. In them, sound waves are created by changing the geometry of the hard and elastic, most often flat, element made, usually, from piezoceramics (type of barium titanate). These emitters well reproduce sounds on resonant frequencies and almost not reproduce on all others.

7. Electrostatic speakers

High-quality high-end loudspeakers include electrostatic loudspeakers, gentle-referred to as electrostat. The principle of action is simple - attraction of a flat membrane to a dressed plate. Alas, for a noticeable manifestation of this effect you have to use very high voltages - Approximately 10 square meters. But in this case, the effect manifests itself so weakly that in order to obtain an acceptable volume of sound at low frequencies, the membrane area should be about 1 square meter, and even more, which determines the large dimum dimensions. It is gratifying that even though the thickness may be small - about 10-15 cm. Of course, designers have to not forget about safety measures when working with such high-voltage aggregates. Sony is one of the few persistently leading the development of electrostats. The dimensions of the columns (1.5 meters in the height and 0.8 meters wide), as well as the working voltage of 9 square meters they speak for themselves. But the columns are well reproduced by low frequencies - for this they use two membranes with a size of 50 × 27 cm. Smaller membranes serve to play medium and high frequencies. Electrostates are not only bulky, but also very expensive emitters. It is unlikely that they are practical for the overwhelming majority of our music lovers and fans of electroacoustics. Just like some types of emitters using special physical effects leading to the generation of sounds, for example, the generation of sound oscillations by plasma. However, the picture is changing if the electrostat is used only to play medium and high frequencies, and the honorable mission of reproducing low frequencies is left behind well-tested dynamic loudspeakers. This path also went to Sony, applying HF electrostats in a number of its musical centers. The range of effectively reproducible frequencies extends from the lowest sound frequencies to tens of kilohertz (it is curious that the exact data of the company does not yet indicate). All experts unanimously converge on the fact that these systems give a particularly transparent and natural sound, to whose quality it is impossible to complain.

Development, manufacture of unique, programmable power supplies for pedals of guitar effects.

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