Speaker cone
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Speaker Cones or loudspeaker cones can be manufactured from various materials depending on driver implementaion ( i.e. box design), desired frequency response for each driver, and cost.
Although the speaker cone is technically the cone shaped part, a cone is many times also referred to as the cone/surround assembly to include the outer suspension called the surround.
Quality midrange and bass drivers are usually made from paper, paper composites and laminates, or plastic materials such as polypropylene or mineral/fiber filled polypropylene. Such materials have very high strength/weight ratios (paper being even higher than metals) and tend to be relatively immune from flexing during large excursions. This allows the driver to react quickly during transitions in music ( i.e. fast changing transient impulses) and minimizes acoustical output distortion.
If properly designed in terms of mass, stiffness, and damping, paper woofer/midrange cones can outperform many exotic drivers made from fancier more expensive materials. A 12 inch diameter paper woofer with a peak-to-peak excursion of 0.5 inches at 60 Hz. undergoes a maximum acceleration of 92 "g" s.
Paper based cones account for approx. 85% of the cones sold worldwide. The ability of paper (cellulose) to be easily modified by chemical or mechanical means gives it a practical processing advantage not found in other common cone materials.
The purpose of the cone/surround assembly is to accurately reproduce the voice coil signal waveform. Inaccurate reproduction of the voice coil signal results in acoustical distortion. The ideal for a cone/surround assembly is an extended range of linearity or "pistonic" motion characterized by i) minimal acoustical breakup of the cone material, ii) minimal standing wave patterns in the cone, and iii) linearity of the surrounds force-deflection curve. The cone stiffness/damping plus the surround's linearity/damping play a crucial role in accuracy of the reproduced voice coil signal waveform. This is the crux of high fidelity stereo.
The surround may be resin treated cloth, resin treated non-wovens, polymeric foams, or thermoplastic elastomers over-molded onto the cone body. An ideal surround has a linear force-deflection curve with sufficient damping to fully absorb vibrational transmissions from the cone/surround interface, and the "toughness" to withstand long term vibration-induced fatigue. Sometimes the cone shaped part and the outer surround are molded in one step and are one piece as commonly used for a Guitar speaker
