Using backgrounds live

["samba -" <sambacomet@hotmail.com>]

After the Beatles were on  I always watched Ed Sullivan for music groups-I 
remember an act called the Singing Nun -a small taper recorder descended 
and 
she recorded a track then sang harmony over it-a strange song that seemed 
to 
be about Domination,or Dominoes or something.I was too young to 
understand,but I got the notion of overdubbing.