Recommendation for sub with high level inputs

Looking to add sub to existing system.   Yamaha Aventage A6A  powering center (Sonus Faber Sonetto ii) , wall height (Infinity Primus P362) , and surround (B&W DM 602), with Rotel Ra1592 integrated preout connected to power fronts (Sonus Faber Sonetto V).  

I listen to (stream) 2 channel music 65 -70 % of the time  - Roon with the hi-fi Rose 250 as my endpoint.

No regrets with the purchase of Sonetto V's, but after having them for a year now, I would like more low end.  

I do not want to connect the sub to the yamaha, thus needing a recommendation for a sub with high level inputs to connect to my Rotel  integrated which doesn't have a sub output. 

2k budget?

Thanks in advance for your suggestions.