Hi
Short answer: Yes.
The best bass in most any room is obtained with subwoofers, properly integrated with the mains. The R11 need subwoofers. Any speaker need subwoofer in other words it is always better to use subwoofers.
To the OP. I will try to keep the rationale for my reply condensed, the subject is however a little bit complex and could require more…
It is important to understand that the reproduction of bass depends on the room. You could have a speaker capable of reproducing 10 Hz to 20 KHz flat, no bump, no variations at 120 dB at 4 meters; once placed in a room it becomes subject to the room influence and to the position of the listener with respect to the low frequency radiators in this example, the speakers. It could be thus, that the placement of your Q950, provides you with a better bass sensation than those of the R11... or it could be where you sit, or it could be the rooms dimensions, or it could be the room construction... or it could be all the above. The last bit could sound flippant or dismissive. It is not.
The perception of bass, to make matter more complicated, is not linear. Let’s suppose the example of a perfect speaker, linear from 20 to 20,000 Hz within 0 db. Flat and no THD, driven by a perfect amplifier. For this mind experiment we suppose also perfect measuring instruments and a humongous anechoic room, so speaker will play as flat as it can. And a perfect SPL meter too . We measure 50 dB at 1000 Hz… We, again measure it at 500 Hz, then 20 Hz. The speaker and room (anechoic) being perfect, we measure 50 dB at 1000 Hz and at 500 and at 20 Hz and... at any frequency in between, 32.01 Hz or 100 Hz .. same sound pressure level: 50 dB. We place a human subject and ask her/him/they to give us her/his/their perception of “loudness”.. How loud are the tones? Well, in this perfect room, with perfect speakers and perfect everything. Playing 20 Hz at 50 dB… This human with perfect hearing will barely perceive the 20 Hz… if at all… Keep this reference in mind. We’ll have to come back to it. Those are the famed Fletcher-Munson curves.
To make matter more complicated, it also happens that in most rooms, the best position for bass is not that for best soundstage, or the rest of the spectrum.It has been studied by people at Harman and by other independent audio scientist, namely Earl Geddes that the best bass in a room in various position is obtain with multiple subwoofers placed in certain positions. Harman preconizes some specific positions for the subwoofers, Geddes advocates a different approach, he calls it quasi-random with one subwoofer in a corner (let’s call it the main subwoofer, the most capable) and the others literally somewhere on the opposite wall and the third behind the listener. In the Geddes approach if the main speakers in this case your R11 are capable in the bass it makes the resulting bass response at the listening positions (plural) smoother and more linear.
The better subwoofers are in general more capable in the bass than most mains, even celebrated and/or expensive ones. A good $1000 subwoofer is quite capable to provide 20 Hz at 110 dB at 2 meters… Few mains are so capable, very few… Cite me two mains that are so capable
… Of course you will say that you never play this loud but remember the Fletcher Munson curves? 100 dB in the bass at 50 Hz is
perceived to be less loud than 100 dB at 1000 Hz and few mains are by themselves so capable.
@sweetchaos at a marvelous subwoofer comparison tool to guide you in the choice of subwoofers, it would be wise to use it.
Independent subwoofers afford you to place them where they provide the best bass, more extended and smooth bass at the listening positions? You place these where they play best, provide you with the best bass and place the mains where they play best.. no reason to compromise. On top o f that there is the subject of constructive inteference. The room play havoc on the bass. You have points in the room where the room adds bass while substracting at other point. Multiple subwoofers canhelp taming those variations.
The process of integration is not easy. Let’s be clear about it. It is however doable and there are methods to achieve it. None are slam-bang-you’re done! It takes days, even weeks to achieve. One thing to be sure in trying to integrate is the necessity of DSP aka Digital Signal Processor/ing and EQ. You will have to learn to measure and to interpret measurements. This will take time and effort
I have to cut it short . You need subwoofers but the integration is not an easy task. It takes time and efforts. It will however (almost a guarantee) provide the best bass you have ever heard, provided you use capable subs and you work on integration. People here will help if you need it. If you have more question. Ask. The level of knowledge from the people here is high.
Peace.