Low volume from sub

Recently added an Svs SB-5000 to my 2 channel setup (Kef q11 metas) and now I seem to have much less bass than when I was just had my towers. During movies I am getting good low frequency rumble but anything above 40-50hz just seems lacking. Which makes any music I play lack punch compared to playing with just my towers I can play my towers with the sub off and get much harder hitting bass than with the sub. Even setting volume to 0 on the app can’t match what my towers produce. Have done the sub crawl and no matter where in the room I was the bass from the sub is lacking.
Sub is connected to via LFE in to sub out and main speakers cross over are set to 80 hz. Sub is sealed and towers are ported but even so I would expect a large subwoofer to have better output than the 6.5 inch bass drivers of the Kef. Any suggestions?