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Looking around for midranges today I noticed the swing twords exotic cone materials. Kevlar, carbon, aluminum, wood pulp...ect...ect..Anyone know if one material really has the advantage of music reproduction? I know some are light, some are strong, all things equal though, wouldn't something light like a simple paper cone produce the most realistic sound? Feel free to post some thoughts........
Posts: 265 | From: ms | Registered: Sep 2003
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Cone materials for a midrange driver in a car need to withstand the rough environment( temp and humidity swings, dirt,etc.). Paper has good tonal response but may not work under the harsh treatment without protective doping of the cone. Carbon fiber based materials offer high stiffness per weight but do not resist resonance(loss tangent) as well as Kevlar(aramid fibers). Kevlar has a higher loss tangent than glass and carbon and is lower in density than both( more fiber bundles per pound). It is sensitive to UV light(turns brown), is difficult to cut and finish and must be treated for UV. It can pick up some moisture( not nearly as much as paper though). Cone break-up is better controlled with Kevlar than some hard and stiff materials like metals. I have some VIFA drivers and they appear to use aramid( could be yellow dyed glass). some insight - Scott
Posts: 26 | From: Anaheim,ca | Registered: Jun 2003
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A good speaker designer will incorporate the cone material into the design and worth around the negatives.
For example heavier plastic cones should have stronger motors and stiffer suspensions, low internal loss cones like carbon fibre and metals should have rubber surrounds and even damping materials on the back of the cone - potentially raising weight so larger motors again.
Paper cones are light, stiff, and if treated will stand up as well as anything. But people want to have aluminum, kevlar, carbon fibre, and all the rest of the exotics to be different.
I would focus more on how the speaker sounds than what it is made of.
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D R A G U L A Let us Prey.... 1966 Cadillac Superior Crown Royale Hearse SS5+ Posts: 3690 | From: Abbotsford, BC, Canada | Registered: Mar 2000
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Thanks for the info. I asked this question because most of the best midranges I've listened to have been paper, best tweeters I've liked were titanium and ribbons. Talking sound quality only, this is just my take on sound though.
Posts: 265 | From: ms | Registered: Sep 2003
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The reason more exotic materials are in use( besides the marketing hype) is that the specific modulus( modulus/density) vs. specific strength(tensile strength/density) for composite materials(for example) are much higher than steel and paper. The difficulty is forming these materials at similar thickness/process as paper or steel. For example: Intermediate modulus carbon fiber specific tensile strength is 12x10^6in and specific modulus is 640x10^6 in. By comparison most metals have specific strength of 1x10^6 and specific modulus of 180x10^6 in. What this means is if you want light and stiff, carbon and other reinforced composites have a distinct advantage... If you learn how to process them.
Posts: 26 | From: Anaheim,ca | Registered: Jun 2003
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Well unless you know that the word 'modulus' is not a specific physical property of anything but rather is a degree element of a physical property of a substance... Kind of like the word 'coefficient' - they are used the came way:
Coeficient of friction and Modulus of elasticity
Both describe the degree element of the physical property (friction or elasticity)
-------------------- Blow your mind - PORT your box!
D R A G U L A Let us Prey.... 1966 Cadillac Superior Crown Royale Hearse SS5+ Posts: 3690 | From: Abbotsford, BC, Canada | Registered: Mar 2000
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Hey Dukk- I am not sure I understand you... Modulus of Elasticity is a directly measured material property. We use tensile test machines to stress a material to its elastic limit then measure the strain(deflection)of the specimen. Modulus is taken from the stress/strain curve. Speaker designers I have talked to definitely know which materials give them the best stiffness(modulus) for the least weight(lowest density). Hope that clears it up- Scott
Posts: 26 | From: Anaheim,ca | Registered: Jun 2003
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