Musical subwoofer under $2000


I’m looking for advice on what vendors to look at as l’d really like to add a subwoofer to my 2 channel setup. The room is c. 30x15 feet or 42 square meters with low ceiling of about 7.5 feet or 2.2 meters. Budget is c.$2,000 and my 2 channel speakers are Sonus Faber Sonetto VIII. My amp offers pre-out connection. I’d like REL but their S range is now too expensive, so something close in musicality would be great. 

sparksgja

 To everyone who has responded to my search for advice I cannot overstate how grateful I am for all the links, personal experiences and knowledge being shared. I don’t know if it’s making the task any easier as it looks like there are so many options to explore. The audiorusty link to the sounddoctor articles is eye opening and thank you soix for your insights.

@sparksgja 

Look used for better value.  There is an ad here on Agon for a pair of S/510 for $2,700.00 (located in Chicago).  I know, above your stated budget but maybe you could up the budget a little bit and make an offer.  Then you get two of the subs you want!  

Just sayin'

 

soix +2. I have a SVS SB2000 PRO. I got in on CL for $350.00! SVS was kind enough to send me the optional foam port plugs. Two of them would help with room acoustics and tonal balance issues. It’s big. I’ve rarely seen larger. Two of them would be beautiful I think with your Sonus Fabers. 
It goes down to 17hz. I never realized how much information was down there (below 35hz.)  in a wide variety of  program material. At lower volumes nothing is missing.