There is an long tradition of the country mountain Dubranator, Dubranader, or just Dubra. Hand carved out of logs were the first resonators, from pine trees that grew on the slopes of their native appalacha. Later band sawed and electronifired, they got louder.
An early Dubranater.
Here is a composition I made out of voice and lute filtered by the Duber:
Here is a SCHEMATIC for the Dubernator. opamps are TL084, transconductance opamps are LM13700. The opamps form a ring pattern of resonant paradox: a state-variable filter. The transistors are for exponential conversion of the crescent-ring, as well as differential voltage input. Each resonator has a MIDO-GENERATOR, which is simply a stable and quiet reference voltage around which everything waves. At the bottom is the power regulating circuitry.