http://hunting-washington.com/calling-bears.htmRead this if you havent.
I have called in bears in the morning, evening and mid day. It doesnt seem to matter much. Granted, I would rather call in morning or evening when I think bears are most active, however, if there is a spot that looks like it holds some bears, why not give it a shot and see what comes.
I have had bears come in on rabbit distress (bears were on the sneak), calf distress (bear charged in) and coyote distress (that bear was charging in quick).
You might have called in bears (or other things) you just might not have seen them.
I called an area a few days ago, sign everywhere, even smelled of bear...called one hour, no luck. Took a nap like 100 yards away, woke up and a bear was within 20 yards. I am not sure if the bear heard the call and took forever to come check it out, or if he was just passing by. It was just a coincidence.

I dont use any scent control, I just watch the wind. Practice, read up on some of the stories on here, watch your back and have fun!