Here is how you can use your external USB bluetooth 4.0 dongle in Ubuntu, even if you have an in-built bluetooth device. My in-built one is buggy, so I bought CSR8510 A10 USB bluetooth for cheap, and using it with my wireless headset.
Steps for manual connection:
Steps for manual connection:
# Step 1: Find alias for my adapter
sudo hciconfig
# hci1: {stuff} (this is the new one)
# hci0: {stuff} (built-in)
# Step 2: Discover available devices
bt-adapter -a hci1 -d
# {bd mac}
# Step 3: Bind bluetooth device
bt-device -a hci1 -c {bd mac}
# Step 4: Connect audio device
bt-audio -a hci1 -c {bd mac}
Worked like a charm for me. Got it from here: http://askubuntu.com/questions/594843/how-can-a-specify-specific-bluetooth-adapter