Hans Luedtke

Organist, musicologist and inventor Hans Luedtke developed special Oskalyd^{[permanent dead link]} extended organs and keyboards that could be used with any desired tone system. Rounded edge hexagonal shaped keys were to be arranged like honeycombs in such a way that intervals would be represented by unique vectors (i.e. a Generalized keyboard). He mentioned tunings with semi-, third-, and quartertones, methods for playing special glissandos, electronic switching between tunings or registers during performances, and he also outlined a notation system analogous to the keyboards and a direct opto-electric recording system.

• DE 388,209. Walcker-Luedtke-Hammer Oskalyd Orgelbau. Vorrichtung zum Erhoehen der Klangwirkung von Tasteninstrumenten, Orgeln u. dgl. 1924.01.19
• DE 403,152. Walcker-Luedtke-Hammer Oskalyd Orgelbau. Tasteninstrument, Orgel o. dgl. (GB 218,252, CH 108,096, DK 34,686) 1924.10.09
• DE 630,202. H. Luedtke. Orgelartiges Musikinstrument. (US 1,919,849, GB 390,574) 1936.05.27
• DE 604,495. H. Luedtke. Tastatur fuer Zwecke der Klangausloesung, der Klangaufzeichnung und fuer Registrierzwecke, insbesondere bei orgelartigen Instrumenten. (US 2,003,894, GB 413,483, FR 756,638) 1934.10.23
• DE 630,202 H. Luedtke. Orgelartiges Musikinstrument. (US 1,919,849, GB 390,574) 1936.05.27
• DE 639,272 H. Luedtke. Ausbildung eines Tastenfeldes, insbesondere fuer Musikinstrumente. (US 2,061,364, GB 459,900)1936.12.02
• DE 749,198 P. H. Luedtke. Tastatur fuer Handharmoniken. 1944.11.17

• Viol-Chaconne (J. S. Bach) organ transcription, 1916
• "Seb. Bachs Choralvorspiele." (1918) BachJb xv, 1-96.
• "Zur Entstehung des Orgelbüchleins (1717)." (1919) BachJb xvi, 62-66
• "Das Oskalyd" (1926) Musik und Maschine 8-9, 385-387
• "Portativ-Positiv-Kleinorgel nach Changie-Prinzip" (1938) 'DIBZ' 39 p. 117 (ref. www.portativo.it - Studi e richerche sull'organo portativo)

• Prepared Piano
• Turkish music (style)
• Microtonal music