The answer to the problems of bad signal outside and a waterproof/sweatproof solution is a new product due out soon from Mi-Sport [inside info!] at mp3players.us.com
Firstly the mp3 player is built in, like their old product, and waterproof. It will also be bluetooth to stream music to the headphones from the phone or take a call, but the headphones have been specifically made super sensitive to the bluetooth signal to avoid fall out outside. This will also drastically increase the inside range from the standard class 2 10m without being class 1 bluetooth which is around 100m and a strong signal. I think it`s out sometime in January.