Subwoofer

Just added a 15 yrs old sub that was on my home theater that I am not using it any more to try out on Cary SLI-80 yesterday.    Wow, unbelievable the soundstage opened up a lot more with very big noticeable.  But the volume was very low and not happy with it so I took the sub out.  Somehow after I connected RCA to sub outputs on SLI-80, the volume was lower right away.  

To Kijanki  
You say you speakers go down to 30 Hz, how you now this?  You read the specification ?

What is level 30Hz ?    -6db or - 10db,   some manufacturer  of small  boxes is claiming  
to go down to 30hz, Don t be nut

The addition of a REL S5 to my system has made a significant improvement in the whole package. My Tidal speakers go down to 32Hz. It did take about 2 weeks to get it positioned correctly but it was well worth it..

Some products have including speakers benefit of subwoofer but not all of. Now a days, Ceiling Speakers have  including features of  subwoofer. So, he said truth at some level.