APTX HD

Hi, Once again I turn to your experience for advice.

I am currently streaming Amazon HD/Ultra HD from my cellphone to a Bluetooth receiver that is APTX HD (whatever that means, sorry for my lack of knowledge).

I wonder what I should do to get more from the streaming experience, in terms of sound quality. I hope to avoid cables to the cellphone (Note8) and computers.

I am not unhappy by any means. Just wonder whether an alternative method will reveal a significant improvement.

Thank you!

B.