There was a discussion here about echo/reverb in relation to this marked rock not so long ago , but I can't find it . http://www.themodernantiquarian.com/site/8455/gleann_da_eig.html
It's the only one I know with an obvious effect.
Plenty in the US where they are often found in canyons caves etc .Steve Waller suggests that the echo was important in the choice of site .