Keep in mind, a lot of CD's have the bit set on for HDCD, but don't use any of the HDCD features. It was an artifact of the default settings.
I found code online and with some hackery converted all of my HDCD recordings to 24 bit FLAC.
Best,
Erik
For OPPO owners. HDCD function
For many years I put the HDCD setting to ON in the settings function, with the confidence that Reference Recordings which use that coding would sound as they should.
I always wondered why those encoded CDs never sounded very good. Indeed they sounded flat and lifeless and at a very low volume.
Lo and behold, I turned OFF the setting today and the same recordings came to life with much higher volume and greater detail.
Is it my machine or a design flaw from OPPO?