I have seen woodcuts etc., depicting street singers and the like, cupping their hands behind their ears, presumably so that they can hear themselves above the general din of the streets.

The other night I caught the end of a TV programme about the relationship which developed between the radical black American singer, Paul Robeson and the miners of South Wales in the 1950s. I'm sure there was a clip of Robeson singing with his hand cupped behind his ear ...? Did anyone else see it?

Anyway, as an unaccompanied singer myself I can confirm that it is a useful technique. Sadly, though, it has been extensively mocked by idiots who are upset that Folk Music is different to fashionable, commercial pop and rock music (which is usually just about all the music that they can cope with).