Below is the picture before I open the roof. You can image that when birds playing at the hexagon, they cannot "see" the inner entrance hole. When they fly in, they need to make "U-turn" to go in to nesting area. Some friends advice me that the flying path is not smooth.
The pictures below show the new Hexagon position. I believe this new position allot birds to play and at the same time "see" the entrance hole. When I removed the Hexagon and did a check, I found out that 2 out of 6 tweeters no longer working. I replaced them before fixed the Hexagon at new location.
As the external tweeters and Hexagon expose to sun and rain, they are tend to break down easier than your internal tweeters. You need to make sure you do a regular check on those tweeters. Remember, those tweeters help you to "publish" your BH to new birds. So, you need to make sure they working all the time.