We are in the process of shortlisting the DACs and SBCs (Single Board Computer). Our initial design requirements looks like this.
A 32 bit 384KHz DAC , If the DAC is designed to play 34 bit 384KHz music really well, it will be awesome at playing 44.1/48Khz . Which is most of our music anyway.
Fully isolated power supplies for the SBC and the DAC. We would be using Linear supplies for both and a shield will separate the DAC and SBC boards to avoid EMI from the SBC corrupting the signals on the DAC.
We would be using the highest audio grade passive components in the analog section.
The SBC would use a Quad Core Processor with one core dedicated for the player by making it run at RT priority. At-least 1 GB of RAM.
The design would move the UI management to a separate Processor to keep the SBC free to only play the media, buffer etc. Most media player software available now tend to over load the main CPU with UI driving tasks, making it more prone skipping lockups etc.
To avoid IO bottlenecks, The player would move the files from the USB / Server to Ram-disk before playing so network / USB bottlenecks do not affect the playback. It will also buffer other songs in the playlist in the background to avoid skips and delays.
The USB drive would support Drives up to 4TB with GPT and filesystems like FAT , FAT32, NTFS , EXT2, EXT3, EXT4.