I agree with Mapman and Bob Reynolds. And also remember when I was thinking of adding a first sub to my stereo and had no measuring capabilities - or understanding, for that matter. So can relate to the OP maybe getting overwhelmed.
I started adding a REL Storm III and loved it. Paired with B&W 804S. The speakers were used full-range, just like REL recommends, and the sub augmented the speakers low frequency output.
Then I got into acoustics, got myself stuff for measuring, experimented, etc. Eventually I bought two Rythmik 12" kits and built very heavy sealed subwoofers. Rythmiks are outstanding subwoofers, and much cheaper than REL.
Initially I set up the Rythmiks to augment the low end and measured and tweaked a lot. My amp is tubed, so I then experimented running from the preamp (also tubed) to each SW crossover, and feeding my main amp everything above 80Hz. To my surprise and despite the lower quality of the parts inside the included crossover, I liked the sound better. I think both the tube amp and the 6" woofers are happy not attemting to reproduce below 80Hz.
I definitely recommend two smaller subwoofers over a larger single one. And by adding even more subwoofers you can make the low frequencies response smoother across the room. See Earl Geddes papers on this.
I started adding a REL Storm III and loved it. Paired with B&W 804S. The speakers were used full-range, just like REL recommends, and the sub augmented the speakers low frequency output.
Then I got into acoustics, got myself stuff for measuring, experimented, etc. Eventually I bought two Rythmik 12" kits and built very heavy sealed subwoofers. Rythmiks are outstanding subwoofers, and much cheaper than REL.
Initially I set up the Rythmiks to augment the low end and measured and tweaked a lot. My amp is tubed, so I then experimented running from the preamp (also tubed) to each SW crossover, and feeding my main amp everything above 80Hz. To my surprise and despite the lower quality of the parts inside the included crossover, I liked the sound better. I think both the tube amp and the 6" woofers are happy not attemting to reproduce below 80Hz.
I definitely recommend two smaller subwoofers over a larger single one. And by adding even more subwoofers you can make the low frequencies response smoother across the room. See Earl Geddes papers on this.