Yes, but your particular room, which otherwise has great acoustics, poses unusual problems when it comes to integrating subwoofers with monitors. Perhaps they would integrate better with your Q3s.
My particular example is just one. I have heard this issue of quality vs. quantity with other monitor/sub systems. I only bring it up because it illustrates for me this distinction between the two types of bass. In this thread, we are actually discussing two full range floor standing speakers systems. I just happen to have heard something similar in my monitor/sub experiments.
Yes, perhaps a sub will integrate better with my Q3s. Interestingly, Magico, the manufacturer being discussed here strongly believes that subs should not be integrated with two way stand mounted speakers. They advice customers to first get one of their larger floor standing models and then perhaps later attempt to integrate subs.
As you have heard with my Q3s, they disappear just like my Mini 2 monitors, which were set up by a pro. So the usual advantage of monitors is not a factor in my particular case. The bass of the Q3 is excellent, so I have no interest in subs at the moment to possibly get more slam for rock music. Those who like adjustable volume on their subs for different music and recordings, like you do, may have different priorities.