the meaning of "behind time"

“Three or four brass bands are playing behind a portiere between the coal shed, and also behind time. Footmen in gay-laced livery bring in beer noiselessly and carry out apple-peelings dropped by the guests.” ------ O. Henry Tracked to Doom

What does “behind time” mean here? Does it mean that the music these bands play is outdated?

Link of the whole story: http://www.literaturecollection.com/a/o_henry/130/