3Taken from the ecasound (1) manpage:

To play an audio object at a given moment in time, the -i:playat, play-at-time, file.ext, params can be used. This will play "file.ext" after position reaches "play-at-time". The time values should be given as seconds (e.g. "2.25", or as samples (e.g. "25000sa"). Parameters 2...N are passed as is to the child object.