I have a pair of GR20s currently connected via a pair of Cardas biwire cables from an Aragon 8002/Aurum amp/pre-amp combo. Previously I ran them via an Arcam 8R integrated. In both cases, I found bass output to be excellent. The speakers were not even run-in when I obtained them and were initially too 'bottom-end-heavy', causing the hardwood floor to resonate uncomfortably on some tracks. Within a week however, they had 'smoothed-out' appreciably. Having listened to a lot of music over the last couple of months, and I find that good recordings sound great with very adequate bass output, while old/bad recordings can sound thin and edgy. Thus, a case of garbage in, garbage out. Good cables are essential. While initially sceptical that cables could make such a difference, I was astounded at the difference the Cardas cables made. Here in Canada, where the main floor of most houses is of the suspended type of construction over a basement, a sub-woofer would in my view likely not enhance the accuracy of the sound, but transfer excess sound energy directly into the suspended floor, especially if is is finished with hardwood. The floor then begins to act as a giant bass drum, and the soundstage suffers.