Blue tooth phone - improve quality
 

Hi

I have a 2009 convertible. I am able to successfully hook up my iPhone 6+ to it for which I am quite grateful. However the sound quality and mic leave a lot to be desired with regards to sound quality.

How can I improve the sound so that I can actually hear what is being said when talking on the phone.

I cannot imagine there is a "factory fix" for something like this.
I have a 12 and don't really have any complains about the sound. It's not great, but good enough.