Abstract: This paper first presents the principle of the electrodynamic
loudspeaker. It particularly shows how few evolutions occurred since the first
device was designed. Then, it describes the loudspeaker drawbacks whose sources
lie in the motor – especially because of the iron-, the moving part and the
suspension. Furthermore, the major goal of this paper is to propose examples of
evolutions which suppress some of the drawbacks. So, the motors presented are
ironless, made with permanent magnets only. Their structure can be optimized to
create very uniform magnetic fields in the air gap where a short coil is
totally submitted to the field. Moreover, the elastomer suspensions are
replaced by ferrofluid seals which guide the moving part. Besides, the moving
part itself becomes a lightweight rigid bulk piston. Eventually, these
proposals prove that evolution of the electrodynamic loudspeaker is still
possible. And the possibilities are of course myriads.
