I made a new thread in What’s New about these products but I see there are questions here that I did not cover in that post.
The volume on the front is only active if you are using the Analog input on the front. You can control everything from anywhere using your phone, tablet, or computer.
Yes, it will find your NAS and display all your songs in the AxiomAir User Interface where you can create play lists and choose how you want to sort them.
The cost of the metal chassis is what makes it so expensive. We will likely bring out one of these in a smaller plastic chassis for less money in the future but that will not work as well in a stack of equipment. There are two versions available with the amplifier built in. The ZA-100 and ZA-1000.
