1, paper materials,
Paper cone diaphragm material is a traditional manufacturing materials, often mistakenly widely considered to be obsolete technology, not suitable for the use of high-performance loudspeakers. Paper cone diaphragm has the advantage of easily processed into various shapes, and does not require complex and expensive molds, and its mechanical properties can be useful in a wide range of effects within the regulation. Unfortunately, yes: no treated paper cone diaphragm on the environment (especially humidity) are very sensitive. Ambient humidity changes, water vapor content inside the paper will change, resulting in carcass quality, and Young's modulus and other parameters change. In addition, although there could potentially be out of the cone diaphragm rigid enough to obtain a wide range of frequency response to respond, but the paper itself is not enough to get within a loss of a smooth roll-off characteristics. Also, a larger deviation of paper production is not conducive to batch product consistency.
Applications include the emulsion-based glue or PVA (polyvinyl alcohol) coating, and dipping a variety of surface treatment methods can greatly alleviate the shortage of these two, these coatings help to cone isolated with the surrounding environment, while increasing the transmission loss Therefore, the unit can be a smooth frequency response at high frequencies. Pulp by adding carbon fibers other fibers can also improve the acoustic characteristics of diaphragm. Same time, through a strict process control and material selection to production inconsistencies paper will improve. Please note that some manufacturers, seeking to aesthetic needs, and in some paper diaphragm spraying the surface of the material in some days to know (God-only-knows), but trick to claim a pair of speakers to improve the acoustic performance of special effects, only the God knows the effect of (God-only-knows, maybe there is damage). Please believe in science, not superstition. As for the discrete nature of the product can be improved by strictly controlling the production process and the origin of materials, quality control.
The same pulp, the internal structure is also a result of papermaking methods, dehydration, drying methods completely different from the physical constants change with it. Papermaking methods fall style with the force of natural absorption, even if the carcass quality of the same thickness and density are different, the former method the thickness of the large density, Young's modulus is small, the internal loss increases; the latter's tendency to the opposite. Pulp cone followed for more than half a century, the reason is that fiber-rich and be free to control the type of the internal structure of the other plastic sheet or metal foil is not freedom, only to change the shape.
Although the paper surface seems like a low-tech materials, but through the proper processing of paper cone diaphragm, but it can also get a good bandwidth and smooth response, fully comparable with the high-tech materials. Experts continue to study the formulation of new paper cone diaphragm, processing and surface treatment. Do not surprising, therefore, based on cheap, old-fashioned paper-based materials will be the latest breakthrough in technology cone diaphragm, re-Hwan life.
2, polypropylene-like material (commonly known as PP)
1976 BBC develop the material used as a substitute BEXTENE. Because it has a very strong damping, design the appropriate polypropylene unit without any balance, you can get a flat in the work area response, efficiency is higher.
Type of material is a polypropylene speaker cone diaphragm is probably the most common application of different materials. Most claim to be polypropylene cone diaphragm material system, in fact will be doped with mineral or other fill material (for example: carbon fiber and Kevlar?). Filler can control costs, but also to change the mechanical properties of the material. Inherent damping polypropylene cone diaphragm is good, as long as the bandwidth requirement is not very wide, to achieve a smooth response to no problem. In addition the effects of humidity is not easy to achieve the material itself and its processing technology error strictly controlled. In fact, because of its stable and reliable characteristics, polypropylene-like material is that many researchers have carried out finite element analysis of loudspeaker unit (FEA) of the material of choice.
As the polypropylene adhesive type of material is not easy, so do not be recognized early. With modern adhesives technology (early 80s) in development has been completely solved this problem.
Now, from low-cost component systems to the first-class ProAC Response 3 and the Hales System 2 signed version of the various speakers are used polypropylene units, such units depends largely on the ultimate quality of the shape of the basin, as well as polypropylene cone formulations Add materials .
Benefits: If the design is correct, get a flat response, very low coloration, good impulse response, frequency divider can be very simple, high efficiency, split a slow vibration. High-quality products can be done with the best of the cone are quite transparent.
This is not to say that using polypropylene material would be no problem. Although there is no quantitative research papers published (at least I do not know), may have a lot of people think we can hear a diaphragm cone made of polypropylene unit or similar viscous viscous phenomena of the performance of (Hysteresis, viscosity of a non-linear phenomenon, reflected in the system parameters in accordance with the system's recent history and continuing to change.) The most common is that the viscosity of plastic materials, due to the viscoelastic creep (Viscoelastic creep, viscoelastic creep is the plastic material under pressure to slow the expansion trend. The process may be linear, may also be non-linear, depending on the material inside the wear and tear). Some people think that viscosity is a voice coil and diaphragm of the then Department skeleton arise from non-voice coil heat generated by the proliferation of voice coil holder, will soften the plastic cone or the then Office of adhesives, softening depends on the voice coil heat dissipation . So a lot of polypropylene in the bass of the resolving power can not be a popular metal dome tweeter a good match.
Despite the fact that the existence of the problem, or imagine, polypropylene cone diaphragm materials, by virtue of their excellent high-frequency response and consistency of performance, high-performance speaker system applications are still very popular.
3, other plastic materials
In addition to polypropylene (PP), the recent years, there have been large quantities of plastic and plastic materials, including TPX, HD-A, HD-I (or above by Audax production), Neoflex (Focal production), Bextrene (a kind of paper pulp from wood pulp the synthesis of plastics, BBC1967 years to develop, as has better consistency and predictability of the material instead of paper, has been replaced by the PP).
The emergence of new materials that efforts to find suitable experts in specific contexts rigidity, damping, density and sound velocity of the best combination of materials. These materials are the advantages and potential shortcomings of broadly similar to polypropylene.
4, resin bonded high-strength woven fibers
Most carbon fiber, fiberglass and ballistic fibers (Kevlar?) Cone diaphragm is such a case. Cone class by a diaphragm or similar fiber cloth and epoxy resin adhesive made. Fiber itself has a high tensile strength, a suitable resin impregnation, material stiffness will be quite large. No doubt, the band weave basin extends. However, the cost of a less smooth frequency response, because the resin bonding material is low in loss. Some people think that irregular fiber orientation is conducive to undermine the standing wave pattern inside the cone, so that a smooth frequency response. Rule of thumb, this phenomenon up to the high-frequency response of the unit has a small impact, we tested the weaving pots speaker unit, high-frequency response is not smooth.
Even the best KEVLAR, carbon fibers, at least in the upper area of work the emergence of a high-Q peak, generally in the human ear's most sensitive 3-5KHZ. Other rigid elements such as metal cone is also true, this will result in a long time listening to the sound field perspective compression fatigue flu (hidden effect).
Many speaker manufacturers have been trying to improve the simple woven fiber cone diaphragms basic structure. A two-tier manufacturers to adopt the upper and lower bulletproof (Kevlar) fiber pieces, the middle is a small silicon resin and a combination of the ball and considerate of the complex formed together. The layered structure is said to rigid very good sandwich material can control the amount of damping. Another speaker unit manufacturers to adopt a similar sandwich structure, with a Nomex honeycomb sandwich. These technologies are very exciting, however, cost is extremely expensive, but other simple materials, and his family the performance of similar, high-frequency response is not smooth, but of degree.
Woven fiber pots unlikely to have viscosity properties (folding rings and centering support films, and even the magnetic circuit system may still have, but that is another topic.) For broadband applications, weaving, fiber pots may not be the preferred material, However, the inherent rigidity and hysteresis characteristics not easily produced, it is suitable for low frequency applications. In addition, the woven fiber is not sensitive to the environment, thermal stability, Ye Hao, subject to direct light / heat (such as the sun) was less affected. Thus, particularly suitable for car audio applications and outdoor occasions.
5, metal-like material
Metal materials for the rise in recent years, a cone diaphragm material. The material discussed so far, the metal damping the smallest, so high frequency peaks significantly, 6.5-inch speaker in the 5kHz peak up to 12dB are also common. However, in the first division the following vibration, the metal cone performance, well, this is the principal of its popular Office.
The most common metal cone diaphragm of aluminum (and alloys), and magnesium. If possible, use a variety of forming and surface treatment technology of metal materials processing, high performance metal cone diaphragm speaker appearance is not hard to imagine. However, even with the best crossover design, the current high-frequency metal pots are also far from ideal, so choice of metal pots, as not many broadband system applications.
6, other materials
Many speaker manufacturers continued to make changes in the basic materials and structural testing, trying to find the suitable for certain applications a better diaphragm material option (or just a larger market demand for products). Layered structure of various types, paper composite, Kevlar, and plastics production complex for the most recent of such material, because it is adopting some new technologies, all of these materials in favor of or against the propaganda must be very carefully considered.
Summary of the material on the cone
Want to stop here, we have clearly the best for high-performance audio cone diaphragm material depends on the actual needs should be selected as necessary compromise. In addition, you have to keep in mind is this: speaker design, far more than cone diaphragm cone material selection. The contours of diaphragm shape, material thickness distribution, folding ring and centering support tablets in different frequency characteristics, voice coil size and materials, magnetic circuit structure, etc. are all speakers play a significant role in the ultimate performance. Dear readers, I mean is that you can not simply of a loudspeaker diaphragm material is used to determine the performance of good or bad. |
