Physics does not adequately explain reflected sound and echo effects. Take as example the echo-producing Echoplex, a magnetic tape device that influenced the soundtrack of a generation.

You stand a long distance from a wall, clap, and listen for the echo. The distance travelled is twice the distance from you to the wall (because the sound has to travel to the wall and back).

The built-in speakers also provided strong sound, which made it great for playing music. Now in its third generation, the Echo Show 8 boasts a better-looking design, with room in the rear for ...