reflection of sound

[denian]

i read in the book. it stated that sound can be reflected by a barrier and the barrier must be large ( 10metre or more ).

why?

[Chi Meson]

In general, waves don't interact much with barriers that have a width that is smaller than the wavelength of the wave.

The "why" for this is a longer explanation.

a wavelength of 10 meters is a low frequency sound; you could hear a hand-clap echoing off a wall smaller than that. FOr any echo of voice, you would want at least a 5 m wall, but the larger the better.