Stanwal is right on. I own Dyn C1's (monitor) with a sub but there was a day when I wanted the C2's (floorstander) more for its looks and the added bass that I heard at my dealer. He loaned me a pair for just over a week. At first I loved them but when seriously listening something didn't seem right. Turns out because of the nearfield listening the bass was no better than the C1's in the sweet spot (elsewhere is was a lot better). Also with the C2's there was a huge vertical wall of sound coming at me.
As far as a sub I partially agree with Learsfool. But only in the FACT there isn't much below 40hz. I think the key to using a sub is to get it to blend with your speakers and not make it shake the foundation (which newbee's with subs tend to do - myself included). When set up properly you will think the deepest bass is coming from the monitors and NOT where the sub is positioned. Also when set up properly the sub will add to the mids making the soundstage a little fuller. The key with adding a sub is getting it set up correctly which is not all that simple. Getting the timing right is the hardest part. You don't want the output from the sub to lead or lag that which is coming out of the speakers.
That has been my experience - yours may vary
As far as a sub I partially agree with Learsfool. But only in the FACT there isn't much below 40hz. I think the key to using a sub is to get it to blend with your speakers and not make it shake the foundation (which newbee's with subs tend to do - myself included). When set up properly you will think the deepest bass is coming from the monitors and NOT where the sub is positioned. Also when set up properly the sub will add to the mids making the soundstage a little fuller. The key with adding a sub is getting it set up correctly which is not all that simple. Getting the timing right is the hardest part. You don't want the output from the sub to lead or lag that which is coming out of the speakers.
That has been my experience - yours may vary