The laws of physics remain what they are. You cannot get deep bass out of a small box and small drivers. The more you push low frequency extension, the higher the distortion. Of course technology marches on, but only slowly. In my own case, I recently replaced the LS3/5a monitors in my study by their most modern descendants, the Harbeth P3ESR. The modern sibling does indeed have more extended bass, and better bass as well (and not just bass - these are truly great speakers), but even so, it is nothing like a true full range speaker. Not in terms of low frequency extension, and not in terms of dynamic potential.
If you want deep bass there are only two possibilities. The first is new full range speakers. The second is subwoofers. As it so happenend I have a B&W PV1d subwoofer in my main system, and one day I decided to experiment and combine it with the little Harbeths. The match was easy to achieve and the sound was spectacularly unreal. You think all that deep bass is coming out of these two litle boxes. The extra power from the sub also gave some more dynamics, even though it still did not quite fill the large main listening room that I was using for the experiment.
So if you are happy with your current mini monitors, I think the subwoofer route is the way to go. If you decide to do this, I have two recommendations, and they both concern room modes. Room modes are the real problem of low frequency reproduction, and they have to be addressed if you want a good integration, and want to avoid boomy and woolly one tone bass. I think you would need to do two things. The first is to use multiple (small) subs - at least two and perhaps more, to smoothen response. See here for an introduction: http://www.acousticfrontiers.com/20101029using-multiple-subwoofers-to-improve-bass-the-welti-devanti...
Have a look at the Audiokinesis Swarm system: http://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/
The second would be to add room equalization like the Antimode 8033: http://www.theabsolutesound.com/articles/dspeaker-anti-mode-8033-dsp-subwoofer-equalizer-tas-204/ I have one and I am very pleased.
Combine multiple subs with room eq, and you have the best of what is possible in a domestic context.
However, if you are using mini monitors because your room is very small, forget about all this, and just learn to live with what you have. How large is your room?
If you want deep bass there are only two possibilities. The first is new full range speakers. The second is subwoofers. As it so happenend I have a B&W PV1d subwoofer in my main system, and one day I decided to experiment and combine it with the little Harbeths. The match was easy to achieve and the sound was spectacularly unreal. You think all that deep bass is coming out of these two litle boxes. The extra power from the sub also gave some more dynamics, even though it still did not quite fill the large main listening room that I was using for the experiment.
So if you are happy with your current mini monitors, I think the subwoofer route is the way to go. If you decide to do this, I have two recommendations, and they both concern room modes. Room modes are the real problem of low frequency reproduction, and they have to be addressed if you want a good integration, and want to avoid boomy and woolly one tone bass. I think you would need to do two things. The first is to use multiple (small) subs - at least two and perhaps more, to smoothen response. See here for an introduction: http://www.acousticfrontiers.com/20101029using-multiple-subwoofers-to-improve-bass-the-welti-devanti...
Have a look at the Audiokinesis Swarm system: http://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/
The second would be to add room equalization like the Antimode 8033: http://www.theabsolutesound.com/articles/dspeaker-anti-mode-8033-dsp-subwoofer-equalizer-tas-204/ I have one and I am very pleased.
Combine multiple subs with room eq, and you have the best of what is possible in a domestic context.
However, if you are using mini monitors because your room is very small, forget about all this, and just learn to live with what you have. How large is your room?