@brian Any news on this?
At the moment I can apply DSP to digital sources but not to my TT output (using Bluesound Node 2 which can act as Roon endpoint or can accept analog input). I did try using the Internet Radio facility by running Nicecast (on Mac Mini) and broadcasting the line input as an ‘internet’ 9local network only) station. I worked but the quality was poor (limited to low bitrate MP3).
Having this facility in Roon would be a great improvement - at the moment the only solution I can think of is buying something like miniDSP product but would prefer to use Roon DSP if possible.