I've used calls for bears, but only after first seeing the bear. Bears seam to have short attention spans and I have found that one really can not over-call a bear.
Typically what I do is find where I think a bear might be. This start in Mid May for me. I look for does and cow elk who are dropping there young-ins. If I find an area with a lot of new fawns I then know 2 things. 1) the area has a high buck population and 2) bears and other predators are likely to be in the area for this is the time of year when really they start on there protein diet. So, this will be the area where I will both deer and bear hunt (elk move too much

, but I'll try to keep tabs on where there moving to). Now lets fast foward to late July.
Now I'm looking for where I think the bears will be. I'm in the same areas where I found the high fawn population and looking for bear sign and there food source. For the most part, I'm watching south to south west facing slopes that have berries and border a thick bushy area. And in the evenings I will spend hours watching these areas to find and critters. In August, I'll first go to area where I have spotted bears.
Calling Bears
Typically I am about 100 to 500 yds away from them when I first see them....not always, but that the norm for me. If its a bear with in about 250 I won't bother with calling and take the shot UNLESS I don't want to go to where the bear is at, prime example is looking at a clear cut and having much debris in the gully between me and the bear or a small creek...something like that. If I see one farther out I'll start calling, the farther out I see him, the louder and more frantic my calling. Often, if a bear is out past the 350 yds mark, I'll have to use two different calls and sometimes 3. As I mentioned they have a short attention span. Often times they will start coming in and then stop eating something else or just start to wonder a direction I don't want him to go, so i'll change calls and start over and MOST of the times, he'll snap right back to me. Once he's in range, we'll pop em. I've taken two bears over the past 3 years but have helped several of my friends get onto a bear taking 7 total using these tools

. I strongly suggest having both a range finder and spotting scope with you. They can be fun to watch and addicting to hunt.
This has proven to be a good technique for me

, hope at least some of this helps!!
Bearmanric, does this sound about right to you??