in addition to the previous review:
I tested the KZ AZ20 together with the VAORLO QCC3056 adapter - this is the latest and most powerful option that is currently on sale.
AptX HD DOESN'T WORK! AptX Adaptive started, but kz az20 simply loses connection every 10-15 minutes. And without restarting it does not restore the connection.
I checked the adapter (QCC3056) on other headphones - there is no such problem.
What we end up with:
Yes, the AptX Adaptive has finally appeared, but it’s impossible to use it normally.
AptX HD doesn't work at all!
It’s still not clear where the declared three modes of operation are (bass boost, gaming, music) - there are only standard and high performance, which do not change anything at all.
Of the declared functionality, only the connection via SBC and the simplest version of the AptX codec works stably.
KZ AZ20 does not perform ALL declared functions and is not worth the money.