You can experiment with room correction in roon in the digital domain for very little outlay and without any physical device at all as roon supports software convolution in its DSP. To do that you need to purchase an inexpensive calibrated USB microphone and download REW (freeware room measurement software) to record and equalise the filters. It is all explained here by our very own @Magnus
It all looks a bit intimidating, but once you get your head around it, it is very simple. Using the RTA feature of REW and the moving microphone method (literally waving the mic around the listening area) I was able to record and equalise the zipped WAV files roon needs in about 20 mins. I cannot remember the last time any upgrade to DACs, amps. speakers, streamers has made such an impact to my perceived SQ.
The next step is hardware convolution where you can get both REW and Dirac enabled devices at various price points from miniDSP. Dirac uses a more complex fixed microphone recording method whereby 9 to 12 fixed measurements around the listening area are taken. If you are starting out I would just stick with REW and the much simpler moving microphone method until you get the hang of the process.
My experience has been so positive that I have an SDH from miniDSP on order, mainly so I can integrate my analogue sources as they are now essentially unlistenable after experiencing what room correction can do.
Unfortunately the miniDSP SDH has been swept up in the new stricter rules concerning “roon ready” certification. It is not currently roon ready and I don’t know what the timescales, if any ,are. I plan to use the device for my analogue sources so I am not concerned. I’ll be experimenting with roon and the SDH also, of course, but I already have a simple REW+roon solution for my streamed sources so it is not a major concern.