|The purpose of a loudspeaker is
to produce sound (move air). The most common way to
attain this goal is an electrodynamic transformation.
Electric impulse is transformed through some kind of
mechanical system (for instance cone) into acoustic
energy (also mechanical energy).
All electrodynamic drivers are based on the same concept; a cone is set in motion by an electromechanical motor system.
electrodynamic driver is composed of at least four systems:
Efficiency of electrodynamic transformation is very low and lays bellow 2% for a typical production speaker.
Speaker's diaphragm must change direction very quicklly
The speaker driver determines the ultimate potential of the entire loudspeaker, and plays a dominant role in the sound of the entire high-fidelity system. There is no such thing as perfect driver.
Major parameters which should be observed by a driver designer are uniformity of motion (pistonic behaveour) with freedom from resonance (self-damping), cavity resonances and magnetic non-linearities. Uniform motion rigidity means accelerations from the voice coil are accurately translated into cone acceleration over the entire driver surface which should result in fast pulse risetime, low IM distortion and a transparent, "see-through" quality to the sound.
Perfect (theoretical) driver would have a cone with a density of air, completely uniform motion at all frequencies, and no distortion from cone, suspension or motor. Sorry, but this is unachievable!