Do I need a subwoofer?

@olfac87 ,

Do you know exactly what series it is? It should be on the back.

The series 80, the first ones, didn't go that deep on the bass, they were 2db down at 37Hz (quick check) and by 20Hz would have dropped a lot. Subs would definitely help for the deep bass.

The series 2 was tuned to achieve much deeper bass. They were flat to almost 20Hz. However, the series 2 to work "properly" required the external equalizer.

I am definitely a subs person, and high pass the mains. It reduces distortion. Would that benefit the 801? It is a trade off. Using the bass of the 801 with external subs will even out the bass at the trade-off of more distortion in the 801s. A challenge and fun experiment to see what you like better. I do recommend for subs learning how to take room measurements. It is cheap and much quicker and more accurate than trying to do it by ear.

Yes to subwoofer(s). My speakers extend reliably to the mid 30s but the additional weight provided by adding two powered subs with 22Hz bass LF extension is substantial. I recommend that you choose self-powered units with built-in room correction for maximum satisfaction.

Yes to the sub(s) they will add serious weight to your sound not to mention enlarging your sound stage.  I am a REL fan but there are other good ones.  Currently using the S/812.  Highly recommended.  

No subs for me please. Have them in the house but after my acquisition of the QLN Prestige 5’s they are no longer in use. 
 

Just my preference not saying anything negative and they worked fine when I was running monitors. 
 

I Robot.

@cindyment They are Series 80s.