low frequencies

I have a pair of Thiel 2.4 in my second system. They were in my main system for a few years. I have owned them for a very long time and have had them in 4 rooms with at two different houses. The Thiels have great low bass extension and texture. Mean really good. But it is tuned flat so not boomy at all. Typical HI-Fi turned bass.  
 

this is 100% a room issue. Try pushing the speakers back so the driver face is 24” off the front wall. The sound stage will still be fine and the bass will be impressive. At that point if you can move your chair around until the bass sound good, sit there. 

Velocityofhue,

I am glad it worked out with a relatively simple fix. Room boundary interference is a frustrating one that can make great equipment sound bad. Moving the seat is 100% a practical solution that works if you have the space.

the 3.6’ (assuming driver face) technically makes a dip at 78hz. Closer to the wall will cancel higher and farther will cancel lower. I think thiel recommends a minimum of 3’ from the front wall which would make a dip at 94hz off the front (other boundaries matter too and can even it out or make it worse, really need to add all of them up and average them). Anyway 3’ works pretty well when not using subs. Less is actually better for the bass. I have found as close as 30” to be fine. As you get closer you lose some of the depth to the soundstage. Pushing them back just a bit might improve your bass a bit more as 80hz and down is critical for bass impact.

I typically use subs and in my main systems I pull the thiels 5’ off the front wall but crossed over at 60hz to sub which fixed the null the 5’ distance caused. Without subs I like to stay 39” or less from the front wall or more than 7.2’. 7.2’ into my room is pretty awesome but my kids run around the speakers and I can ’t deal with it lol.

Boundary calculator here if you want to see where the nulls are in your room.

http://tripp.com.au/sbir.htm