Flat panel speaker PK conical speaker

The birth of the flat panel speaker technology is a revolution of the speaker technology, which represents a major innovation in the field of speakers. Because it completely changed the traditional speaker has been a piston type motion of the sound principle, and replaced by a millimeter in the form of random vibration. Its vibration mode was first discovered in 1992 by the British National Defense Agency under the DRA. After several years of research, the theory of the distribution of sound theory was improved. In 1996, the British NXT company announced the establishment, and is committed to the NXT flat panel speaker technology into business, professional and home and other practical application areas of research.

Its technology has the following advantages:

1、In the case of the speakers, the design idea is to make the vibration film as a whole for the piston type with the wide frequency range.

At low frequencies, the displacement of the diaphragm is decreased with the increase of signal frequency at 12 dB per frequency. In this time, the acoustic wave in the air is longer than the size of the diaphragm, and the real part of the radiation impedance of the film increases with the increase of the frequency, so that the output of the acoustic power output is basically constant. But as the frequency continues to rise, a qualitative change occurs when the acoustic wavelength is reduced to a considerable size of the diaphragm. The real number of the radiation impedance reaches a limit value and no longer continues to rise with the frequency, while the radiation impedance is kept constant. At this time the sound power output of the diaphragm is beginning to fall at a rate of 12 dB per frequency. Although the axial pressure drop is not much, but the energy output diaphragm was defined in a space angle and an increasingly small in. In order to solve this problem, a small film can be used to make the inflection point of the radiation impedance curve in the range of the frequency range. But in order to produce a low frequency range of the volume change, the diaphragm must be able to withstand a great deal of amplitude. Therefore, the speaker designers are forced to compromise, the vibration diaphragm of the multiple drive unit size. Large diaphragm unit provides the required volume range of low frequency; small diaphragm unit improve the directivity effect at higher frequencies (but with changes in hearing, sound position deviation angle axial loudspeaker treble part signal will be attenuated to different degree obviously). However, the frequency divider frequency will bring a series of side effects, such as phase distortion, reactive load increase, and the characteristics of the capacitor and inductance coil core saturation characteristics related to sound quality issues, etc.. Even if the above measures are taken, the directivity of the loudspeaker system is still unsatisfactory. The larger the listener's angle to the axis of the speaker, the more high pitched voice is cut.

NXT technology completely abandoned the design of the traditional piston movement, and using a whole surface is almost random vibration, rather than the regular vibration of the diaphragm to replace. After it is motivated, on each unit area of the soundboard can independent random vibration, so that we can be conceived as a whole soundboard is composed of many micro loudspeaker array. Each micro speaker unit is capable of radiating an uncorrelated signal, but their signals are finally synthesized together, forming an acoustic output from the macro to form a.

This random vibration of the plate is very different from the conventional vibration film, because its power is directly output to a relatively constant frequency of the plate mechanical impedance. Because the air near the plate is also in a random manner, so that it can reduce the effective air load, so the radiation impedance is not important. The mechanical impedance of the soundboard to replace the original radiation impedance position, become effective power consumption. When the external force is constant, the velocity is constant, so the output sound power is independent of the frequency. The directivity of the loudspeaker is no longer limited by the size of the diaphragm, regardless of the size of the area to do, will not make the high frequency output as the traditional speakers are limited to a narrow space around the front axis, its high frequency can be achieved 18KHz above. But the point is far superior to the traditional speaker, even in the audience and the soundboard is perpendicular to the plane, the treble does not significantly weaken. The speaker system using NXT technology no longer requires a high frequency and frequency divider.

2、The traditional loudspeaker paper cone for piston movement, the sound of its front and back is the opposite of the sound. Therefore, in order to avoid the sound energy offset in the low frequency range, you need to add a big baffle or a sound box. This is not only heavy, but will inevitably lead to the use of power is only half. One of the important characteristics of NXT is that it is a positive and negative side of the same sound. Thanks to the radiation characteristics of complex distribution pattern, and it seems irrelevant phase characteristics of radiation element from the far field acoustic soundboard produced in the front and the rear sides are the same. From the back of the sound, not only will not be offset with the sound power of the positive, but will be a good superposition together. So the traditional loudspeaker system for acoustic sound box in order to avoid isolation before and after the offset each other do not need, and also an increase of 3 dB spl. Wooden speakers inherent in the case of the sound, the sound of the wood stained, that is, the sound of the program itself is not some of the characteristics, which is a distortion, and other issues have been no longer exist, the product becomes thin and light (5 cm), convenient transportation.

3、For the traditional speakers, the relationship between the sound pressure and distance, in theory, according to the "inverse square law", that is, every increase in the distance, the sound pressure is reduced to 1/4, which is the sound pressure level of 6 db. In NXT technology, the variation of sound pressure is close to the linear relationship with the distance. That is, the distance of each additional distance, the sound pressure only decreases to 1/2, that is, the sound pressure level of 3 db. So, a flat speaker sound can spread farther. If the use of a power of 1 watts speaker, in a distance of 1 meters from the speaker, a flat speaker and a traditional speaker of the sound pressure level is equal; then the speaker at 4 meters, the sound pressure level of the flat panel speakers than the traditional 6.

4、When the traditional speaker is working with a large amplitude, the typical amplitude of the bass speaker is more than a dozen. The resulting series of problems: the distortion caused by the part of the voice coil, the distortion caused by the air gap, the position of the branch and the paper cone. In the NXT technology, the amplitude of the sound board is very small, and the typical amplitude of the intermediate frequency is measured in microns. The minimal displacement of exciter coil, coil coil will not be part of a strong magnetic field out of gas gap or uniform elastic elements beyond the linear elastic range, completely avoid the distortion caused by these factors, but also has a strong power overload capacity, all kinds of machinery in the traditional loudspeaker by large amplitude caused by the damage problem here does not exist.

5、The traditional lifting device of the piston vibration will cause a lot of standing waves (sound waves in the sound box), and the sound waves will be reflected when they meet the boundary. Especially when the two driving units are close to each other, the acoustic wave is reflected in the wall or the interior objects. If this phenomenon is very serious, the voice of the sound clarity and resolution will be greatly reduced. So when listening to the voice of the changes in the position of the tone is very obvious, coupled with its relatively sharp point, so that the indoor acoustic design, furniture placement, listening to the voice of the location of the selection is very important, which gives a lot of trouble to the lack of professional knowledge. In NXT, the radiation board with traditional loudspeaker diffusion was completely different, it is not the voice from a fixed point from the space, the divergence of acoustic waves in the encounter boundary, boundary resonate, so the sound field does not produce Valley point. Plus it has the characteristics of the rate of good directivity and sound pressure level decreases with distance change is small, so the distribution of the sound in the room is very uniform, is the traditional speaker incomparable, even in the best listening area outside, also can show very good sound positioning performance.