Old-fashioned and Modern guitars http://www.rdiaz.org/rd-art%207.html

Flaw Detection Guidelines
http://www.rdiaz.org/rdvideo1393.html

Ex.1/ 00:14 solo I Heritage by Ruben Diaz (Tanguillo)
Ex.2/ 09:53 solo II Heritage by Ruben Diaz (Tanguillo)
Ex.3/ 01:19 solo III Spain by Chick Corea
Ex.4/ 02:09 (answer for the magazine)


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Cracks may or may not affect the instrument
https://youtu.be/UEYjusOIgfY?t=14s