Configure your Mac using Vox and Audirvana Free for bit-accurate Audio with OS X
Playing bitperfect-audio with a Mac OS X and is a little bit complicated because Mac-Computers always use a fixed bitdepth and samplingrate in the MIDI-setup. But there is a lot of software available to listen to your HighRes-Files with automatic changing of bitdepth and samplingrate.
You should not edit, configure or change the BIOS (= "Open Firmware") of your Mac!
Installing OS X
Usually Mac Users do not have to install the OS X, buy any Mac and you will be ready...
However, OS X Version 10.10 (Yosemite) or better 10.6 (Snow Leopard) is recommended for the bit-accurate playback with Mac OS X, because these versions allows the activation of the "Hog-mode" (takes exclusive control of the audio output device) as well as "Integer mode" (directly addressing of the hardware e.g. bypassing mixing buffer, filters) without expensive additional software.
Configure OS X for bitperfect playback
To get bitperfect audio with Mac OS X check out the configuration below: