Horn loudspeakers guide sound through a changing cross-sectional area. The rate and shape of that change is part of the acoustic design, not merely the outside appearance of the enclosure.
A compact technical conversation
In this Questions with Tom video, Tom Danley discusses expansion ratios and why the geometry of a horn matters. It is a useful starting point for anyone who wants to understand the physical design decisions behind horn-loaded loudspeakers without reducing the topic to a marketing label.
Watch the original
Watch Questions with Tom: Expansion Ratios on YouTube. Use the current Danley page below as the manufacturer source.