Room echoing

[bapak]

Have a couple of classrooms that have smooth, unadorned walls, resulting in some echoing?
I have seen "somewhere" some Styrofoam type material that can assist. Or, I guess, putting up some curtains on non-existent walls.

Suggestions always welcome.

[dtaai-maai]

Have a word with admin in one of the local universities. Let me know if you haven't sorted anything out by the end of May (when my hols finally come to an end...).

[moja]

curtains would help or just a few mats or rugs. Anything 'soft' will stop the echoing; the amount you need with depend on how big the room is.

[Gralee]

You could line the walls (and/or underdraw the ceiling, if possible) with acoustic tiles - these are the tiles which are covered in tiny holes - in a regular or irregular pattern. They basically absorb the sound energy from 'noise' and prevent it from being reflected back into the room as more noise, in effect preventing 'echo'.
You could also hang flags from the ceiling - this might also serve an educational as well as a practical, purpose.

[chopsticks]

Fix empty cardboard egg trays to the walls to act as acoustic cones.

[bapak]

A "sound guru" from Sydney has suggested polymer wallpaper.
Any suggestion on a local wallpaper shop?