Horns sound very dynamic and reproduce fast transients in the music. Of course, there are some problems associated with horns. They can be hard to build. Poorly designed horns can impart colorations to the music, or sound just plain nasty. And horns designed for producing low bass notes must be very large.
Horns are acoustic transformers.
Because of this transformation, the horn driver can be a fundamentally different design to most radiating-type drivers. Chambers alter the frequency characteristics of the horn and change the operating conditions for the driver. A more complete theory of horn loudspeakers can be found in the bibliography of the references section . A white paper called The Quadratic Throat Waveguide by John Murray gives an explanation of horn theory. Murray describes how the increased efficiency and bandwidth of modern compression drivers has resulted in changing priorities in horn design.