I've had a really hard time finding in-ear headphones that would stay in. I exchanged a couple emails with one of the Klipsch customer service reps and decided to go ahead and order them (the R6). While waiting for them to be delivered, I found all sorts of people complaining in various forums online about them falling out. Regardless, I remained hopeful.
I got the headphones, and sure enough they fall out easily. I'm using the right sized buds -- they fit snugly and would be fine if not for the issues described below). I figured out what the problem was with how they are designed, and then took my valuable time to write out a detailed description of the issue(s) and even recommended ways they could be improved to help avoid the falling out problem. I got no response. I sent it a again a week or two later. No response again. A simple "Thank you for the recommendations" at a minimum would have been appropriate. Not impressive customer service. And of course, no way I could find to call and actually talk to a human being to follow up on that either.
Simple version of my detailed, and ignored email: the connecting wires between the over the ear parts and the in-the-ear parts are way too stiff. When firmly in my ears the wires themselves push up on the over the ear parts "lifting them off the tops of my ears; they then fall down (once over the tops of my ears) and they weight and momentum *then* pull the buds out. Also, the imbalance of the weight of having the controller part just on one side exacerbates the problem.
I hope the new Bluetooth headphone model referred to above will have solved the issue(s). I also hope Klipsch improves the customer service.