Good sound but don't stay in place.

I was thrilled when I saw this design as I had a similar set from Aiwa that I really liked until it was stolen. The Aiwa's were $25 and were just a plastic ear "bud" that went in the ear and the neckband was rigid. The sound was very good for the price and they were comfortable. However, since they were stolen and now discontinued, they didn't do me any good. I saw these Sony's and decided to give them a try even thought they were double the price of the Aiwa's. These have rubber ear buds that are very comfortable and the over the ear and around the neck is also comfortable. The neck band is flexible which allows them to collapse into a small easily portable package. The sound is very good for this price range including tight bass response. I don' thave too much experience with headphones at this price range, but I do have a pair of $100 over the ear Sony headphones and a $300 pair of over the ear Grado's. At $49.95 these sound pretty good. However, my range of motion at work cause my shoulders and neck to press against the neckband which dislodges the seal of the earbuds which of course affects the bass and overall sound. I do move a lot at work but I'm not running or anything like that. Even just typing while wearing these is causing the seal to repeatedly be broken. Very annoying. I read several other reviews of these by people who excercise with them and they said they stay in place, so maybe I got a lemon. I have tried all 3 sizes of the included buds. I have to remain completely still to enjoy a good listening experiene. As they are now, they are not acceptable. They are going back.