When playing 24bit/96kHz FLAC files through direct streaming using either primary sound driver or speakers (Digital Power Station) the ‘B’ button does work.
I also played pink noise to see if there’s any SPL difference between ‘B’ button and no-‘B’engaged. Surprised that the meter doesn’t recognize the sound difference that I’m currently hearing with my ears. Using C weighting average with a digital sound meter from Minolta.
I haven’t tried higher sample rate music. Would need to purchase them and test it out.