I had the 121s in a 13' x 15' room. They are in between the 120/126 in terms of size/frequency response. They worked great in my room. Though I do have a fairly wide opening in to a hallway which helps with bass I think.
11' x 11' might be pushing it with the 120s, unless perhaps you have a lot of flexibility for placement. The stereophile measurements show quite a boosted bass even, as JA says, taking in to account the usual hump in his measurements:
https://www.stereophile.com/content/mbl-radialstrahler-120-loudspeaker-measurements
So that could be challenging.