The only application in the App Store which lets you to stream ALL the Iphone audio to any bluetooth device (from your car hands-free device to any standard headset) with an integrated player to make it easier. You will be able to stream applications like spotify, youtube, Radio, Podcast, VLC, etc...
Download it, test it and if you like it and works for you just activate it from within the application.
Please send to me directly any comment, suggestions, problems, etc... firstname.lastname@example.org
Notes about the Audio quality: The audio is adapted to the quality and capabilities of your hand-free or headset device, therefore the quality maybe different in one or another device. We recommend to download and test the quality before buying the complete version.
Video with a demo: https://www.youtube.com/watch?v=U0yJssDOg2M