What is the working principle of the Loudspeaker?


    An audio signal source such as a microphone or recording produces an electrical "image" of the sound. That is, it produces an electrical signal that has the same frequency and harmonic content, and a size that reflects the relative intensity of the sound as it changes. The job of the amplifier is to take that electrical image and make it larger -- large enough in power to drive the coils of a loudspeaker. Having a "high fidelity" amplifier means that you make it larger without changing any of its properties. Any changes would be perceived as distortions of the sound since the human ear is amazingly sensitive to such changes. Once the amplifier has made the electrical image large enough, it applies it to the voice coils of the loudspeaker, making them vibrate with a pattern that follows the variations of the original signal. The voice coil is attached to and drives the cone of the loudspeaker, which in turn drives the air. This action on the air produces sound that more-or-less reproduces the sound pressure variations of the original signal.
ztzaudio

seems to me you have your answer already, almost.

the ‘identical’ thingy bothers me some. Mics aren’t perfect and neither is or are the components engaged in reproducing its mimickry. naturally then there will be some loss or distortion during and or thereafter with respect to signal integrity.

speakers themselves contribute wildly to the loss and distortion as does the microphone itself and its preamp, cable, etc.

even the acoustics of the room in which the recording or playback is delivered will boost or detract from the noise they exhibit.

so, IMO the working principle of loudspeakers is to take the electrical signals received and excite the transducers in such a way as they vibrate themselves and the air surrounding them so varying frequencies are transmitted in an audibly discernable manner that sound is heard.

albeit, from instrument to speaker is a long and twisty road. things will not ever be identical or exactly duplicated at our ears relative to the orig performing venue.

true too even if a mic is not in use and all signals are transmitted electronically.

as for all these losses and distortions, here is where the ‘brain’ comes into play. it takes up the slack and tells us if a thing comes close to the orig that it likely is being , it being ‘replicated’ .

this advisement the brain sends us reminds us of two things. we’re hearing a recording… and how well done it may or may not have been recorded and rendered.

it also advises us we need to spend a lot more money so we can believe we are either at the orig venue or the artists are in our room.
Dynamic loudspeakers are just linear motors sized and shaped to produce certain frequencies.
Planar magnetics have the voice coil in the diaphragm.
Ribbon speakers, the ribbon itself is the voice coil.
Electrostatic speakers have no voice coil or magnets. A charged diaphragm is driven between two high voltage grids.
Then there were Hill Plasmatronics........
They are all transducers, devices that translate one form of energy into another. The operating principle is transduction.