http://arrrrv3dzzoluxubt3p24lpn7qu4rxuem3fb4kcmboji3dgpkgt4b2ad.onion/worter/bit-perfect-audio
This means that the higher frequencies would be boosted prior to writing the tracks, resulting in a better signal to noise ratio. If you use a dedicated CD device or direct line, the emphasis bit will be detected, boost removed, and you hear what you expect.
Unfortunately, if you read the tracks as data for copying to flac, the boost will persist and you'll have a heavy high frequency version of the soundtrack.