MBL 120 vs 126

Hard to say.  The stereophile review quoted MBL as saying the 120 is particularly flexible in working in different rooms.  So maybe your small room would work.

Does it work to go with the model you prefer, and then just see which room it works in?

I've actually kept my eye on the used market regarding the 120.  I've thought if I ever wanted MBL again that would be the one - an updated version of the 121, that also goes deeper in the bass.   Though really that's a pipe dream for me at this point.

But the 120s are very rare on the market.  I notice though there is one for sale on stereonet right now:

https://www.stereonet.com/forums/topic/577622-mbl-radialstrahler-120-loudspeaker/

Thanks very much for your comments, Prof.

I do have the option of using a room that is 13' X 40', but would prefer the smaller room because it is near our main living area and keeps me near the action.  I would guess that with this size room the 120 is a more viable option?

If I went with the 126 it would likely need to be new.  The 120 I might be able to do used.

Thoughts?

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.