In terms of new physics or fundamental technologies (as someone pointed out, planar was also from the 1930's), there is nothing new since then for loudspeakers. We are still pushing air to make soundwaves and the method of generating air motion is down to moving diaphragms/membranes/cones.
Where there has been new technology advances is in electronics i.e. amplification via solid state devices and digital technology (both for amplification and source recording/playback). The advances in electronics allow for much greater power to be send to speakers which have allowed for smaller speakers that can more readily fit into modern living space and even automobiles to generate the same or greater SPL (sound pressure level) as large horn speakers of 1930's. Solid state and digital technologies have allowed for miniaturization of components and also reduce costs and ease of mass production to enable the mass public to enjoy high fidelity music. This is where there has been advances. In the 1930's, high fidelity music was limited to the wealthy and the few.
I myself enjoy low powered SET amps and single driver high efficiency loudspeakers and I do enjoy a good horn speaker and generally prefer them to modern speakers. And in this regard, I don't feel that modern, contemporary loudspeaker systems sound better than the vintage ones that have been setup appropriately ... at least to my ears. FWIW and IMHO.
Where there has been new technology advances is in electronics i.e. amplification via solid state devices and digital technology (both for amplification and source recording/playback). The advances in electronics allow for much greater power to be send to speakers which have allowed for smaller speakers that can more readily fit into modern living space and even automobiles to generate the same or greater SPL (sound pressure level) as large horn speakers of 1930's. Solid state and digital technologies have allowed for miniaturization of components and also reduce costs and ease of mass production to enable the mass public to enjoy high fidelity music. This is where there has been advances. In the 1930's, high fidelity music was limited to the wealthy and the few.
I myself enjoy low powered SET amps and single driver high efficiency loudspeakers and I do enjoy a good horn speaker and generally prefer them to modern speakers. And in this regard, I don't feel that modern, contemporary loudspeaker systems sound better than the vintage ones that have been setup appropriately ... at least to my ears. FWIW and IMHO.