I’m surprised that DBX was used for noise reduction on CDs, since CDP, by design (CD standard), has its own noise reduction by pre-emphasis and de-emphasis. Each CD provides "flag" that can turn de-emphasis on, but it is almost never used. The main purpose of it was to reduce hiss of the analog tape, but almost all recordings these days are digital. DBX encoded CDs would have value only for somebody who either doesn’t care about the sound or has DBX processor.
Dbx encoded discs
Is anyone familiar with dbx encoded discs? I have a single recording (Pictures at An Exhibition/Nigh on Bald Mountain), but there were other recordings made. I have not found a catalog though.