Electric / mechanical amplification of acoustic instrument

An acoustical musical instrument such as a violin, a guitar, or a bell, or bagpipes, is a passive system in that the human input powers the system.

The human uses muscle power to input energy (in the form of scraping the bow, strumming the strings, swinging the bell, or squeezing the bagpipe)

Obviously the human uses Skill and Technique to somehow modulate or control the input energy, but we are taking that as given here.

The physical structure of the instrument acts as a kind of tuned oscillator / radiator system which converts the human input energy into audio output in the form of sound waves.

People want LOUD instruments to make a LOT of NOISE. Usually this is done by taking the resultant (quiet) output of the physical instrument, and using a microphone/pickup to convert the acoustical output of the instrument into electric signals, which can be electrically amplified and then used to drive a loudspeaker system.

However I don't want to listen to a loudspeaker, I want to listen to a LOUD musical instrument.

Now the idea here is that we can make the instrument louder by adding more mechanical energy downstream of the human input but upstream of the soundwave radiance.

Proposed is some kind of electro mechanical stimulation system that fits into a stock acoustical instrument. The wire comes out of a suitable orifice (of the instrument, do keep up) e.g. the violin f-hole and is plugged into mains power. The human user stimulates the input components of the instrument (e.g. scrapes the bow along the string). the instrument starts to convert this input energy and modulate it into sound vibrations, which somehow kicks the electro-mechanical input device into action, reinforcing and enhancing the vibrations and producing a LOUD SOUND from the instrument.

I suggested electrical but I see no reason why a direct mechanical system should not work instead, perhaps powered by a steam engine or falling weight.