How do I know if I need a sub woofer?


My system at the moment is not important as this question would be relevant regardless of of what I am listing to at the moment. 

sounds_real_audio

I just changed amps...when putting the system back together, I first listened with no subs, then added 1 and later the other...each made a significant improvement in overall sound, not just deep bass...main speakers are large floor standers rated -6db at 23hz...

This is a timely post, at least for me. Two days ago I figured I'd bite the bullet and pull one of the subs from my HT setup into my two channel system to see if I liked it.  I did, but it didn't seem as seamless as I'd like, and even though low frequency is supposed to be non-directional, I couldn't shake the feeling that it was.  I spun three records and was ready to "call it a day" and return the sub to it's dark home in the basement, but figured I'd try a second subwoofer, mainly because so many here and in other forums I trust recommend the practice.  Good grief! I was amazed and listened to one record after another until 3 a.m. rolled around and I didn't want to be useless at work so I hit the sack. I've spent the entire day champing at the bit to get home and listen some more - now I have to figure out how to sneak two more subs into the house (my back/knees won't take moving the HT subs back and forth)! Low frequency slam was definitely a hallmark of this experiment, but the soundstage became deeper and wider, and everything just "grooved" more, I don't know another way to explain it. 

Just when I thought I had found the perfect sub woofer I found one that is more adaptable to my active life style

 

https://www.youtube.com/shorts/B10g4gq062s