Speaker Cones - Fabrication, Components, and Functionality



It truly is taken as a fundamental truth that most speaker factories can duplicate an current design’s frame and magnetic structure, but having the soft parts suitable is an art. The cone, surround, spider, and dust cap include several on the secret ingredients in speaker design. Selecting the correct soft parts is hard, together with the most important elements becoming the components, process, and fabrication. Get additional information and facts about speaker cone manufacturer


Speaker engineers know that 3 crucial physical properties determine a material’s suitability for use in loudspeaker diaphragms - stiffness, low density, and internal damping. Stiffness, in particular, determines the bending wave velocity, and for any given design, the frequencies at which the initial break-up resonance occur. This resonance within a diaphragm determines the transition point above the frequency point at which the diaphragm loses piston motion and response becomes rougher.


The high Young modulus (as well as the steepness of your cone’s body angle as well as the diameter) determine at what point issues come to be nasty. The degree of internal damping, or loss factor, determines the material’s effectiveness in suppressing such resonances, which can be particularly critical near and above the upper resonance. Endumax absorbs really high amounts of energy. While this property was made for ballistic protection products, the properties also make the material especially suited for speaker diaphragms as there will likely be significantly less energy reaching the surround edge to reflect back.


The ideal supplies will have higher velocity and higher damping, but for those who've used titanium cones and domes, you understand that in numerous cases these properties are mutually exclusive. Endumax, that is similar to aramids (e.g., Teijin Technora and DuPont Kevlar), offers a great mixture of each damping and velocity. Materials for instance Endumax have low density so using various layers will result inside a stiffer and stronger cone with low weight.


Loudspeaker cones are most generally formed from paper pulp, but plastics (e.g., polypropylene) are also well known, and sheet material is usually vacuum thermoformed (like melting hot cheese more than a form), compression molded, positive/negative molded (or injection-molded) into the preferred shape. Metal cones are also used. Other high-tech solutions that have accomplished success include things like a sandwich building with skins and honeycomb or foam cores.


In the final years, a number of notable composites for speaker cones and diaphragms have already been introduced for the speaker business. These involve woven, cross-ply layers and non-wovens, glass fiber, carbon fiber, and aramids (e.g., Kevlar), thermoset, and thermoplastic resins.


Normally, a specialist cone manufacturer fabricates cones for speaker assemblers, but the largest offshore speaker companies typically have their own in-house cone fabrication facilities. Over the last 25 years, I've worked with several of your suppliers that present components towards the cone market and have visited many of the cone factories in Asia as well as the US.


At first glance, every person is using exactly the same approaches, but for those who dig deeper, the subtle differences is often substantial. In this article, we take a look in the basics of generating different forms of cones - but what I go over right here will not commence to touch on the secrets that the cone companies have learned from decades of experience.


Paper Pulp Cone Fabrication

The process starts with sheets of different forms of pulp. The pulp may well come from Douglas fir or exotic blends, which contain a little of eucalyptus from Brazil, Cambodia, or Australia (incredibly stiff), other specialty pulps from New Zealand, or from the hemp family (Fostex and Dai-Ichi like banana leaves), kapok seed fibers (the poor man’s Kevlar), or different synthetic fibers. The pulp recipes, additives, pulp slurry beating process, and cone forming tactics all contribute towards the loudspeaker cone’s qualities. Young’s modulus (speed of sound), tan delta (internal damping), and mechanical parameters (e.g., tear strength, burst strength, and so on.) are all elements that separate the toy cones from the audiophile, studio monitors, electric guitar, or pro sound diaphragms.


Other considerations are wet strength and moisture regain. Will the cone fail if used within a humid environment, will that studio monitor sound precisely the same on a humid day, and how vulnerable is it to UV, fungus, ozone resistance, and so on? We don’t think of the speaker cone’s selection as geographical but kind surrounds usually do not survive in Brazil or Mexico - between corrosive city fumes and microbial foam eating bugs, you are going to see lots of rubber or thermoplastic elastomer edges.


Appearance continues to be another consideration, and there are many secondary surface treatment options that add elements that cannot be completely achieved using the cone paper qualities. When the recipe is chosen for a certain production run, the proper paper pulp is soaked in hot water to get a time frame determined by the manufacturer. Pieces are torn off the wet pulp sheets (by hand or by machine) and thrown into a water-filled pulp beater. The beating process disperses the fibers though also fibrillating (fuzzing them up) so they'll tangle together, thereby holding the cone with each other. The majority of the sector uses the old-style beating machines, which give potentially great fibrillation. Often hydro-pulpers are used, which might be faster in making the slurry but might not do substantially fibrillating work on the fibers.


Additives are thrown in to the beater (e.g., salts to hold the dyes that are mostly black), and after that the contents are mashed some much more. Within the case on the beating machine, there is a beating wheel, that is progressively brought closer to the beater bedplate because the pulp is worked into a slurry of fibrillated fibers. Eventually, this soup is transferred to a holding tank, which has an agitator to keep the slurry dispersed and homogenized in the tank. The pulp’s fiber length, density, and “secret sauce” are variables that distinguish unique speaker cones intended for subwoofers, midranges, musical instruments, and so on.


There are actually 3 prevalent cone paper forming strategies: pressed, semi-pressed, and non-pressed cones. Within the case with the pressed cone, the pulp slurry might be dumped into a bin and drained via a fine mesh screen. The paper fiber solids are left on this screen soon after the liquids have already been drained out of your bin. The remains are removed in the mesh and deposited onto the cone pressing machine. Heated positive and unfavorable metal cone-shaped types then press the pulp. The remaining water steams out with the cone, that is removed in the forming tool.


If the cone’s density is as well low, then the cone may be as well dead-sounding. In the event the cone is pressed also really hard and thin, then breakup (“cone cry”) will be far more noticeable, specifically at higher sound levels. The cone density and pulp composition affects the internal loss (“deadness”) in the cone material, that will contribute towards the speaker’s sound quality. The speaker cone shape (profile) is a vital factor within the speaker’s sound top quality and efficiency. In the event the cone is straight-sided (probably with concentric reinforcing ribs molded in the cone physique), it will be the strongest and much more rigid at extremely low frequencies.

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