The audio quality is distinctly better than the original!
Thanks to the high quality background music provided by the official soundtrack, and thanks to elmer and SOX, our converted tracks are squeaky-clean.
Whatever tool Falcom was using in 1993 was simply not up to this standard.
That's great to hear (pun intended)!
I can't imagine that my ADPCM conversion is really doing anything that's
noticeably better than Hudson's, even though I handle clipping and rounding a little bit differently to the official OKI algorithm for the chip.
Falcom's original audio didn't even come close to maxing-out the signal level, which probably hurt the amount of noise that you hear in the originals. So, if your new audio is set to a similar low volume level, then my changes to the clipping would never be activated.
I suspect that the real winner here is using SOX for the conversion from 44100Hz to 16044Hz.
The technology for doing that cleanly, with all of the necessary pre-filtering, has improved by leaps-and-bounds since the 1990s.
You just can't use SOX for the conversion from uncompressed-WAV to ADPCM for the PCE/PC-FX, because their algorithm is broken.