Bit perfect is seen by many as the holy grail of computer audio.
By sending the data unaltered to the audio device, you improve sound quality!
This is of course nonsense. If nothing is altered, quality remains the same.
So where is all the fuss about?
As others in this tread already pointed out, audio quality might suffer if the OS meddles with it.
Now all OS do. They are designed with multiple audio streams in mind so all streams must be resampled (if needed) to the rate set in the audioo panel. All streams are converted to float, mixed, dithered and converted back to integer.
If you have a 16 bit DAC (or you are that silly you set the OS default to 16), you have all your sources dithered and as this is the LSB, at -96 dBFS.
If the DAC allows for 24 or even a 32 bit data path, the LSB is again dithered but who cares about -144 dBFS or -192 dBFS as no component in your playback chain is able to resolve this.
However, taking Windows , when resampling signals close to 0 dBFS, there is a measurable distortion.
This can be solved by avoiding the Win audio stack (WASAPI/Exclusive) or if you want it system wide, using EQ APO
A debate has been long raging in the audio community that Windows isn't fit for use in a high resolution audio system. Sceptics counterargued that bits are bits and Windows audio degradations are a figment of an over-active audiophile imagination. I decided to investigate this as I kept...
www.audiosciencereview.com
So the little problems we have using Win for audio can be easily circumnavigated.
No reason to sacrifice DSP like DRC, EQ or even VC for a silly purist ideal.
The essence of EQ/DSP is to improve the sound by being as bit imperfect as hell!