baffle extension

[Professor smith]

This concerns a typical 2 way bookshelf speaker mounted on a stand. I heard somewhere that if you put a piece of wood or other material the same width as the baffle under the speaker extending all the way down to the floor so that the baffle is extended, this improves bass response. Anyway I tried it with a couple of pieces of cardboard and it seems to affect the imaging although I'm not so sure.

Can someone explain if this trick really works? What does it do?

Another trick is to put some absorbent material like a pillow on top of the speaker and this seems to focus the image. Is this reccommended?

[LineArray]

I think those measures affect the baffle diffraction ...

There is some discussion currently in the "Roundovers" thread.