An interesting variation on the old with a completely new twist is a breakthrough from Disney Research at Carnegie Mellon University in Pittsburgh. It's a speaker that can be made by a 3D printer that can be created any shape. This is basically an electrostatic speaker using a thin conductive material and an electrode plate separated by a layer of air, but made via a 3D printer.
The big problem with this type of transducer is that it has virtually no low frequency response, but the fact that it can accept unusual shapes allows it be very directional. This might allow a super directional speaker that could be used in a museum, for instance, where the sound only emanates directly in front of a painting that you're looking at. The speaker can also emit ultrasonic frequencies, which can be coded to allow identification of the device, as you'll see in the video below.
The 3D printed loudspeaker probably won't be commercially available for 5 years or so, but it does illustrate that audio is breaking out from the norm of the last century into the future. You can't help but feel that the "big breakthrough" that leads to a more perfect transducer is right around the corner.