Well the quietest method is old Tony McClebs secret, but sometimes it's just to cold out
(39 degrees in western Md. this morning)
the next best that works for me, especially on hard hunted public is quiet cluck and purr on a slate or diaprahm
I did get busted last week when I was setting down the slate and a neck and head periscoped up over the crest of the ridge at 35 yards-----gambled on one set of clucks to many