More Bass

You could try to add an equalizer, shiit loki seems like a great choice plus I think you get 15 days to return it. 

@ricmech23

+1, I would recommend a Martin Logan Unison pre-amp/streamer/dac with ARC room correction. ARC would make your speakers sing and integrate the bass with the room, you would be stunned. On sale now at like half off:

50% off at $199:

Add Furutech Rhodium plugs to one of you power cords if possible. you may want more ones you try them. That will help to boost bass. NCF ones are the best. 

I think you are muddling the quantity of bass with its quality.

Any fool can give you bags of booming bass for beans but quality down there at 20Hz costs real money and you will get huge speakers as well.

By the way, there is no musical instrument that goes down as low as 20Hz so down there you will be reproducing mostly noise.

Sealed vs ported plus room setup acoustics probably hold the key. The manufacturer can help you with room/speaker setup and ported vs sealed expectation.

For me, subwoofer setup was in itself instructive, because I wanted bass without noticing the addition, except when doing an A/B. If I were use to booming, less tight bass my requirements might have differed. Also, integration of subwoofers is likely easier with your floor standing speakers vs smaller speakers. I realize that exceptions exist, so you do have the option to add subs in the future. My speakers have a 3dB down point similar to your speakers and my RELs were easy to integrate once I treated the room.