4. June 2020 - A letter from Dr. Achong (published by PANArt in Sept.)
Last Updated on 12. October 2021
A letter from Dr. Achong (PDF) (Engl.) / (German), published by PANArt on Facebook on 9/4/2020 as an expert opinion, states that every external shape is imaginable and that the lens shape is an aesthetic decision.
See also: Spanish : https://handpan.es/pan-freak/documentos-tecnicos/traduccion-del-documento-escrito-por-el-dr-achong-sobre-la-ausencia-de-relacion-entre-el-sonido-del-hang-y-su-forma
Letter is from 4.6.2020
Death of Dr.-Achong: 29.6.2020
Published by PANArt 4.9. 2020