Hi everybody and thanks for the suggestions.
I feel guity to have withheld salient information. The problem to cure is a +6dB increase in the frequency response between 1200 and 6300Hz as estimated from using the Stereophile Test Record 3 and a Radio Shack SPL meter (on a highly reviewed speaker). As said above, the DSPengine of the JRiver software takes care of the problem - my guess was that the Loki could work as well, given its particular characteristics. My bias is that a 6dB difference (equal to 4 times the acoustic energy) over such a broad frequency range is beyond any room treatment or similar. This apart from the fact that other speakers such as the Piega Coax 10.2 or the Gallo Ref 3.5 sound and measure perfectly ok in the same room.
The question really is, whether anybody with a decent analog rig has personal experience with the Loki+ and an idea about whether switching it in has any audible consequences apart from those the Loki is designed to perform. .
At the price of the Loki+ I think it is a no-brainer; I just have to try it. After all a new Loki is of the order of 0.3% of the new value of my living room rig....