I have used a pair of 18bit 5500 for a long time and I really enjoyed them. Bought a pair of ATC scm20asl on the side but sold those.

The Meridians sounded just so much more juicy but with insight. I have compared a pair of DSP5000 24/96 with a pair of DSP5000 18bit and found the difference to be smaller than I expected.

I went from DSP7200SE to 8000SE and found the difference significant.

The 7200SE is much more refined speaker than the 5500, but the configuration is similar. So I think that the configuration of the speaker matters more than the resolution of the DAC. The DSP6000 is an impulse corrected (drivers on both sides of the enclosure) system with a sealed box. I suspect it will load room modes more evenly and has faster, more realistic bass. So in my opinion, in this case AI may have been right.

Main: DSP8000SE< 218 < Farad Super3 TMCB < PS Audio P10. Room correction: Focus Fidelity.
Second: Fostex Fe206NV2 < Audio innovations 500 valve amp < Wiim Pro +
Study: DSP33 < Reviver < MS200
Server: ROCK + Tidal on NUC, fiber on 2x cisco 2960, HD-Plex LPS.
Gone: DSP7200SEu, DSW, DSP5500mkI & DSP5000mkI, 508.20, 210