Definição do conceito
[ENG] In late 1908, Edison had introduced wax cylinders that played for nominally 4 minutes (instead of the usual 2) under the Amberol brand. They were made from a harder (and more fragile) form of wax to withstand the smaller stylus used to play them. The longer playing time was achieved by shrinking the groove size and spacing them twice as close together. | ... | Edison made several designs of phonographs both with internal and external horns for playing these improved cylinder records. The internal horn models were called Amberolas. Edison marketed its "Fireside" model phonograph with a gearshift and a ´model K´ reproducer with two styli that allowed it to play both 2-minute and 4-minute cylinders.[18] Conversion kits were produced for some of the later model 2-minute phonographs adding a gear change and a second ´model H´ reproducer. These kits were shipped with a set of 12 (wax) Amberol cylinders in distinctive orange boxes. The purchaser had no choice as to the titles. | SOURCE: https://en.wikipedia.org/wiki/Phonograph_cylinder
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[FRE] en 1909, l´Amberol, en cire, aux mêmes dimensions que le Standard Edison, mais avec un sillon deux fois plus fin : 200 spires par pouce (environ 8 spires par mm), donc une durée double, soit jusqu´à 4 minutes 30). | SOURCE: https://fr.wikipedia.org/wiki/Cylindre_phonographique
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