My experience with wood in boats has been that it's less subject to vibration and flex than resin fiberglass plastic. I can see where that cone can fail sooner than pulp with heavy use before the coil burns up.
Atmospheric conditions definitely affect any material, such as the dashboards of automobiles cracking in the hot sun of the desert Southwest in the USA.
And placing speakers near heat register's or in direct sunlight in a room.
But I am interested in finding out if most speaker manufacturers rely on the data from their own testing of materials when engineering a driver, or are they relying on the materials suppliers data?
I have to assume that the Polypropylene types of cones are produced under high temperatures with mold machines and I have seen first hand how inconsistencies can occur during the manufacturing process.
Many many years ago I worked in a plastic injection mold factory and saw how that Whole process worked with delrin plastic pellets being vacuumed into the mold machine and heated and injected into large molds under extreme high pressure, there were times when there were inconsistencies and they were usually caught in the ISO 9001 QC process... They used to use instron machines to test failure rates and then they would chart them.
It would just be interesting to know the research put into failure rates and materials selected to reproduce sound efficiently and give long service life.
The Infinity kappa series with the dome failures is a crying shame example, especially because just such a short time of life span that they have & people having a hard time backward engineering the materials to produce something that can create the same Sonic properties of the original domes.
You'd think there would be access to the proprietary ingredients of the materials and the specifications necessary to remanufacturer replacement parts.
I've seen a lot of plastic failure over my lifetime in one way or the other.
And recently had to replace plastic water outlet part on a 2014 Buick.
Yeah I know heat cycles on automobiles are going to shorten the life, but even in this example the engineers have to figure out what materials will give the longest service life..... Speaker manufacturers should be no different in their engineering.
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