Depending on what type of music you listen to and how loud you listen to it you may need to add a subwoofer system to them, but if you are replacing a non-subbed 2-way speaker with the Neumanns, they should blow your current system clean out of the water.
I have DSP and Parametric EQ capability already through my WiiM Ultra. My Fiio K13 DAC also has EQ functions (though I haven’t messed with them).
Forgive me for having doubts that the Neumanns would blow my current system “out of the water.” I am sure the Neumanns are great, but my Satori Helios Textremes and BMR HT Towers are no slouches by any measure. Upon further research, I discovered that both pair produce lower THD in the midrange at high SPLs vs the Neumann 310s, Kii 3s, and D&D 8Cs. And the Helios have absolutely absurd bass dynamics for their size. They are one of two speakers I’ve owned that truly have zero need for subwoofer augmentation (though I use an REL Carbon Special anyway).
Further, when one considers the cost of the drivers in the Helios and BMR Towers (DIY and factory-direct respectively), the Neumann’s and similar ilk begin to lose appeal. I have a hard time believing Neumann are equipping their monitors with drivers that would justify >$300 each if sold separately. In other words, I’m unaware of any largish companies with marketing departments and dealer networks that are equipping their <$10K speakers with $300 drivers. And through my DIY experience, I’ve learned that price does generally correlate with performance when it comes to drivers. The caveats to that are some compression-driver tweeters and the Tectonic BMRs.
Anyhow, last night I made some small position and EQ adjustments to the Helios’ and the resulting performance left me wanting for nothing. The performance was nearly as good as I recall from systems anchored by $50K Rockports and $100K of components, arguably better in some regards (at least better than the Atria 2s in terms of bass). I get that the Neumanns have the theoretical advantage of a dedicated midrange. However, my past experience is that a top-tier two-way speaker will often outperform a 3-way. It really depends on the individual driver quality and implementation. I’ve encountered quite a number of mediocre 3-way speakers under ≈$8K that were lacking in midrange resolution compared to mid-woofers in the $200/each range.
No doubt the KH420s are a top quality monitor, but I think I’ve concluded I’m content with my current setups(s). It’s not as though my current speakers lack monitor-like linearity or distortion levels.