Hi Rob.
Apologies, I overlooked that. You're streaming DSD. In that case, you would indeed need a separate EQ.
However, are you aware that DSD content is initially recorded as PCM (analog-to-digital conversion) and mixed and mastered in the regular WAV format?
Therefore, I don't see any real added value or improved audio quality in DSD. After everything is finalized, there's a conversion to the DSD format, making things more complex.
I also have a high-end setup (Accuphase Class-A amp and B&W speakers, as well as excellent studio monitors). I use an ADI-2 Pro FS in front of both environments ("Home Recording Studio" + HiFi area), achieving a quite nice sound quality.
More importantly, I can take advantage of all the fantastic features the ADI-2 Pro offers – Auto Reflevel, dynamic loudness, PEQ (specifically for headphones) are very useful. Also the ability to run the Bit test to ensure lossless audio transmission end-to-end.
Feel free to proceed as you wish; I just wanted to share my experience as both a dedicated musician (guitarist) and someone with an ambitious setup for recording and HiFi.
Take your time exploring and forming your opinion. Perhaps KaiS can provide more insights on this topic; he is a studio professional and contributes excellent posts on related matters in this forum.
Not sure whether you really need attenuators in front of your horns, maybe the PEQ might help already, but sorry, in terms of horn speakers I have no experience, leaving this topic to somebody else.
BTW .. horn speaker systems are / look really cool, sadly I had no occasion yet to listen to such a system, would be interested though
Have a pleasant Sunday evening.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14