1er class Permanent Colonist / Local Civilisation Data Sheet / Draft68-Asrani / 120-16
The Shinoko-Okani, or Crystal Organ, is the main musical instrument one can find in an Asrani Okan ("temple") and is composed of a vertical stack of cone-shaped resonators made in "crystal" (the corresponding Asnari word "noko" only refers to a transparent matter, but it is more probably ordinary glass than classic lead silicate crystal, given the low technological level of this civilisation). The whole is put into rotation by an inverted Archimedes screw, regulation of the water level ensuring a constant feeding pressure and so a stable rotating speed for the resonators.
Some scholars specialized in pre-space Occidental Music have found similarities between this instrument and Franklin's glass harmonica, even if the latter had hemispherical resonators mounted on an horizontal axis. On its side, the Asrani design is quite neat since the water flow passing through the Archimedes screw is also used to wet the resonators, an uniform repartition being obtained thanks to centrifugal forces and progressive increase in diameter of the glass cones.
The crystal organ is operated while cross-legged in front of the instrument, by rubbing the phalanges pads (or the external side of the thumb) on the periphery of the resonators. The players are always preteenage females from the priest caste, because of their impressive dexterity and better hearing. The produced sound is quite ethereal and disorienting, because the predominant range of this organ (1-4 kHz) is just between the frequency domain where the human brain use phase differences to locate a sound and identify it (<1 kHz) and the frequency domain where volume difference between each ear is used (>4 kHz). It explains the non-official term of "angel's organ" used by the few colonists having heard recitals from this instrument, as they believed that an invisible spiritual creature was "summoned" from the music (see D68-A/48-17 for physical/mental health concerns about this instrument)
The Crystal Organ is not only used for religious offices but it is also the only communication mean (besides writing) between the different castes, as a priest is not allowed to speak to a worker (and vice versa) while the instrument is able to reproduce the sounds of the somewhat chanting Asrani language.