Speakers dedicated magnetofluid seal status?

【 Summary 】 experts pay close attention to the speaker component that provides an expert on the speaker symbol works and how to work better. United States magnetofluid seal company made a perfect complement to this article, discusses what is magnetofluid seal, why they would use in bass, tenor and treble unit; and the development of new technologies. There is no doubt that the reader already should be seen in the loudspeaker advertising "magnetofluid seal" and "liquid cooling" or "terms" magnetofluid seal suspension and also the writings from the speaker manufacturer read benefited magnetofluid seal description. But magnetofluid seal in audio industry application in 25 years, more than 5 million speakers only, now in use is fully integrated to look at high-fidelity speakers in the audio quality and the relationship between magnetofluid seal. 1 background magnetofluid seal by suspended in fluid carrier tetraoxide iron ultrafine particles composed of, firstly, for NASA (National Aeronautics Space Administration of the United States) research and production. Magnetofluid seal company formed in 1968, the NASA authorization magnetofluid seal technology research and development. Magnetofluid seal applications including bearings and seals, such as computer hard drives, optical scanners and loop device semiconductor operations. High-performance robot system in stride motor use magnetofluid seal to improve stability. Recently, a new generation of DVD players and high-speed application CD-ROM and DVD-ROM drive to halt magnetofluid seal laser servo actuator of vibration to seek and focusing more stable, also simplifies production operations. Speaker manufacturer uses magnetofluid seal is because of its heat conductivity. Magnetofluid seal can reduce the level of voice coil burn, and the air gap in magnetic magnetofluid seal in static magnetic (a uniform set of radiative forcing), you can suppress the voice coil. Due to the impact magnetofluid seal magnetic are attracted to the voice coil magnetic field, when the voice coil moves to the center of the air gap magnetofluid seal like a spring-like role seems to have a resilience in maintaining concentricity, thus preventing collisions and bee audio and voice coil, which is only a partial use of a static magnetic levitation effects. Reduce friction and speaker voice coil former splint another factor is the lower working temperature voice coil, which limits the voice coil bulking and cleanliness of air gap. Even if magnetofluid seal very simple lubrication can also reduce voice coil former splint friction caused by the collision. Magnetofluid seal can also inhibit the dust or particles into the air gap and also to prevent the voice coil and air gaps occur erode phenomena. So for the life-saving and voice alarm loudspeakers almost always use strict magnetofluid seal to UL certification testing. Many speakers manufacturer in treble and baritone unit adopts magnetofluid seal have achieved significant results, but still needs to be a more appropriate magnetofluid seal for bass unit – need a low viscosity and high magnetization of magnetofluid seal to make magnetofluid seal itself can stay in the air gap in even in large stroke is also not existing bass unit designed for great changes. About seven years ago, the bass level magnetofluid seal be commercialized. The first company in the subwoofer speaker using magnetofluid seal is a professional audio producer, followed by the car audio manufacturers. Not high-fidelity speaker company first started about five years ago magnetofluid seal unit of bass, today there are many commercial magnetofluid seal products can be used. 2 bass sound quality improvement magnetofluid seal usually transfer response stabilization time (when the signal ceased and the capacity of the speaker, then stop). Damping material because of its direct role in the circuit and soon entered into force, rather than a function in the cone or supported on-chip, just like with the "ex post" damping treatment. If the bass unit for high frequency response has a peak, magnetofluid seal will this situation under control, and side effects than with passive crossover network solution. When you move in the cone, magnetofluid seal can reduce the voice coil inside and around produces certain mechanical noise. Perhaps the biggest difference is that you hear, you cannot hear. When the voice coil heat up, the speakers sound will change — usually in the field of sound pressure level (or more high pressure level) while playing music in an extended time period. Because of the many magnetofluid seal inhibition reaction caused by power compression effect, use the speaker sound characteristics magnetofluid seal the entire playback time becomes more stable. 3 temperature rises and power compression amplifier on the heat sink is a well-known mark, this is because most of the amplifier is only less than 75% efficiency, and greater than 25 percent of the power is wasted in heat. A power amplifier 100W output power music about 75W and 25W thermal. But when 75W music power signal to the speakers, almost all power is a heat dissipation in the drive, and only a very small part of the signal is to convert the music output. Even if the sensitivity of the highest attainable only speakers 5% efficiency, the use of damping the best ball treble and medium density paper or polyester cone subwoofer unit efficiency is close to a 1 to 2 per cent. Now that your speakers are on the receiving amplifier in 1W/m level tested impedances and frequency response. Then open the amplifier. In the CD player to play an hour later, the speaker then measured once found significantly elevated. impedance For T/S parameter, voice coil temperature lead speaker voice coil of DC resistance there is an upward shift so Qes has offset value occurs. This led to drive the low-end and high-end response has a loss. Divider network turning point because the offset speaker impedance and obviously offset. Figure 1 and Figure 2 two group curve shows a 4 inch audio speakers in the 35W FRF at work. The first group of speakers did not use a magnetofluid seal, curve immediately measured, another is 45 minutes after the measured. The entire frequency range has 3 ~ 8dB of loss, in the high-end output has a strong sense of loss; article 2 of the 4-inch speakers use magnetofluid seal processing, test under the same conditions, please note that only the output 1-3dB variations in high-end response is only a slight offset. Magnetofluid seal can help keep the speakers linear response. Eliminate some is commonly referred to as the negative power compression. Figure 1 no magnetic fluid, 35W power compression when map 2 with magnetic fluid, 35W power compression when 4 spectrum pollution to defer irrespective of frequency response and its typical application to determine the loudspeakers of the basic measurement method, the complexity of that Giga technologies can also be created. Use of spectrum pollution test, speaker of the "noise" can itself be revealed, spectrum pollution is tone intermodulationMethod of measurement of distortion, intermodulation distortion typical of only two test tones, but music including many tones, all speakers are a small amount (or more) of the bee codes, quack, noise control, and other unusual sound. Spectrum pollution produced using a variety of test tones at the same time (50 or more) fed to speakers. Each tone about 1Hz bandwidth and a few Hz separated this test signal close to the music of complexity. Deane Jensen on the basis of this technology to engage a diverse design and write an article for the AES papers (prepress, 2725; 1988, at its 88th session in Los Angeles) discusses this in detail. Bell Laboratories in SYSid acoustic analysis test system provides spectrum pollution tests, Audio Precision One use a same steps called the FASTEST. Interestingly, the FASTEST AUDIO PRECISION that leaves the production line is a pair of rear speakers sound and automatic friction bee for automated testing and QC procedures. If you have a sufficiently high dynamic range (actually is and SYSid is using a called synchronization and technology almost). Then the different speakers in the proper operation of the design can be evaluated in a virtual resonance it corresponds to the degree of freedom. In this test, the speakers built-in self noise tends to fill the space between the tone, even if there is a slightly decreased tone. For example a diaphragm height enough, relative undamped metal ball treble unit will often have noise. When the treble unit is more excited tone test signal, all resonance is motivation and have an impact on output. May be a significant medium caliber metal ball treble unit "acoustics dust" reduces 30 or 35dB, a quality very good processed fiber soft ball treble unit may produce minimal noise and most are just to pass discrete test tone, the speaker's own noise reduces 40-50dB or more. Why this is so important, and that's what's important and magnetofluid seal? actually expressed mixed just spectrum speaker quality the most important unique test. If a speaker's spectrum pollution is low, then music atmosphere and inner voice will not be garbage sound masking by the speakers. Crude and speakers will be to tone between into waste. (Figure 3, Figure 4 indicates whether when spectral pollution with magnetofluid seal. ) Figure 3 no magnetic fluid spectrum pollution (1 "ball treble speakers 1W) Figure 4 with a magnetic fluid spectrum pollution (1" ball treble speakers 1W) 5 resonance magnetofluid seal cannot help halt the conical diaphragm direct fault, but when a distorted voice coil skeleton magnetofluid seal, when will dramatically reduce resonance. In fact, initially mainly use magnetofluid seal in the bearing and computer disk drive precision spindle motor of distorting the resonance on damping. The skeleton is to help speakers voice coil wire winding is forming in the sound playback in a more rigorous symbol, because shaking from the voice coil must be crossed to reach cytoskeleton is cone or dome diaphragm. Any include skeleton, resonance before it reaches the diaphragm will pollute the sound quality, therefore this unwanted radiation energy will go in the room. In the air gap, the skeleton is damped magnetofluid seal, so its "noise" is weakened. A assess magnetofluid seal is made of a non-cone cells, only with a voice coil, supported tablets and dust cap, skeleton of noise in the absence of obvious magnetofluid seal is audible, but has the only magnetofluid seal unit is significantly much more quiet. In about 20 years ago when the pioneer company for the first time on the ball when using magnetofluid seal in the treble, they had tested the same phenomenon. In ball treble unit diaphragm and skeleton is very closely connected to the distortion of the spine (and distortion will decrease as a result of the function magnetofluid seal) is the most dramatic. But in the unit has a large cone area, took place in the framework of vibration effects than the cone direct shooting motions is much smaller, so the unit's performance depends on the choice of a high quality engineers cone even select magnetofluid seal damping. 6 hole technology magnetofluid seal application in bass unit there is another aspect, is the appropriate Chamber openings, using holes to prevent magnetofluid seal sputtering technology, because the resulting pressure behind the voice coil (from magnetic structure surrounded by air) with open-circuit, dramatic attenuation unit modem noise. Attenuation unit modem noise to maintain clarity and fidelity is important (Figure 5 outlined various bass unit hole of the zoning plan). Figure 5 bass speaker hole sketch in dust cap after the cores. In the period after impact, bringing together in the dust cap after the air will be blown out, and on the impact of the forward, dust-proof CAP will bend inwards, two situations can produce unpleasant noise. Dust cap last may even be blown away (Overture 1812 concert "," leave a deep impression). in many bass unit core hole both to reduce dust cap following chamber pressure and in order to help cool the voice coil. To the core hole is not without problems, both fees will reduce the magnetic induction (such as small diameter cores). In this case to prevent pressure generated by the gas dust cap or opening of the voice coil skeleton there in dust cap following cone on the hole. By magnets inside the perimeter of the scope, cores, as well as up and down between the space composition of splint a Chamber. When the downward impact of volume, voice coil into this Chamber pressure increase. If there are no openings, surrounded by air forced at high speed from the voice coil air gap by, if large voice coil itinerary will sputter magnetofluid seal. Then you can set the following splint hole. Or, if core has openings, cross hole allows the splint Chamber and perforated core. The splint hole can also be successfully applied to relieve the pressure. Supported tablets and basin rack between the Chamber should openings to relieve the pressure on them. Extension piece is available from the bass unit basin rack opening to see the Brown braided fiber. Although branch tablets look is a breathable fiber, but treated fiber air resistance is still very large. With the appropriate Chamber hole technology, voice coil air gap of air velocity and Eddy current noise can dramatically lower, however,No application magnetofluid seal will speaker unit produces friction sound voice coil and the bee codes of the opportunity increases. No hole technology, through the air gap (from no hole air Chamber) high-speed air abortion angry backlash effect of air bearings and with too many sharp whistling noise. But when the Chamber appropriate openings and application magnetofluid seal, airgap modulation noise can be completely eliminated, this is because the air gap is sealed and because magnetofluid seal prevents the skeleton of the distortion of vibration. 7 air modulation noise cone speakers with many internal Chamber: supported tablets, and voice coil rear (from magnet internal and composition of the space under the splint). Because of the driven unit (voice coil) before and after the move, cone/supported tablets/dustproof Cap with compression and together in the production of vacuum chamber. This can cause the air aspiration noise (air modulation noise), or more, make the drive unit diaphragm part bent or produce parasitic tone. Beware the viscosity temperature curves and drive efficiency and the role of bandwidth to select optimal viscosity magnetofluid seal is important. When the typical working temperature, high viscosity magnetofluid seal of damping effect can be used as a complete application design factors. When working in high temperature voice coil usually, what you choose to make the magnetofluid seal viscosity drive unit band response will not be in a normal working temperature effects of magnetofluid seal. The reduction in viscosity magnetofluid seal will offset the effects of high temperature during power compression effect and frequency response does not have a noticeable change. Early design role of accidental application magnetofluid seal is more use of magnetofluid seal very high damping characteristics. Magnetofluid seal must not only be applied to the control of high-end imaging, but also apply to restrictions on the treble unit of low frequency offset. In the 1970s, a kind of Japan's Studio with listening speakers completely eliminates the divider network (thus making their products into the United States market and audio enthusiast market sale) which applies a thousands centiPoise high viscosity magnetofluid seal. Today, most APG (audio product level) magnetofluid seal of viscosity is only a few hundred centiPoise, or less. Homemade Hi-Fi speakers dedicated magnetofluid seal performance has reached the United States the level of similar products APG, and price/performance advantages are very attractive and can provide guidance, it is a Chinese speaker great Gospel.