VOX - is subscription based if you want to get all of its abilities working you gotta pay for them.
I'm not a fan of a simple playback app actualy costing me money to play my own files. so I only use the free version to playback the FLAC FILES I RIPPED USING MY WINDOWS PCs which can now be played using my new Mac.
playing 16/44 files with VOX on my 5K Retna desktop with Logitech powered desktop speakers which playback 24/96 files too, comes across clean and undistorted as playing them off my Windows 7 box using JRivewr or fubar 2000, ever did.
in fact, I feel VOX does a better job playing files than does itunes. the sound is more transparent, and open. the sound scape is wider too. usually,.
there are apps for windows which will extract audio files in their native resolution, regardless what it may be. there are as well apps which will upsample exisitying files, for what reason I've no clue. Great DACs should convert files well despite their word lengths or bit rates, and it is very common to find the overwhelming abundance of files in user libraries are 16/44 anyhow.
on the subscription app topic, I'd look to something other than vOX. I'm not keen on how Vox markets their subscription pricing. every few days there is anotehr offer yet the numbers never seem to add up to what Vox is actually offering.
ROON seems to be as close to a one size fits all app that has come out lately and is very flexible as I understand it.
my world is in flux so I'm not using any mainstream subscription service what so ever presently. in fact I'm not upgrading my JRiver app any more either. I did try to load it onto the MAC with its MAC version but it failed miserably to enable me to use it.
as for playing high res files with your Mac you'll need to poke around in the audio settings within system utilities and see what can be done there. of courdse you'll need to add an output device or hardware which can receive and decode files whose word lengths are higher than 16 bit.
good luck