I agree with Kaboom about the good aspects and the mediocre aspects of the 11Ls sound . The slightly larger Quad 12L has all the good parts of 11Ls sound and less roll-off of treble - better extension and without any annoying peak/dome resonance . The 12L has more bass than the 11L and quite enough for some music styles and various craftily mixed or mastered popular recordings , though it loses control in the bass if driven very hard , or when presented with the very lowest pitched notes that are more often still present in recordings of Orchestral Classical music and most large Organ recordings .
Quad's small floorstanding model - 21L - has better bass extension and control for Classical music and Organ , etc ... but will not play well to headbanger volume levels , but is fine in small to medium sized rooms . The Quad 22L floorstander goes louder in the bass , but its bass sounds a little behind the pace of the rest of the music to me - it is not nimble , but some listeners may like it , hence listen carefully and with some of all the music recordings/types you expect a speaker to work with .
The 11l seems to me to be in the Quad range specifically for people who demand very small speakers as priority over other matters , and who want a simple clear sound when listening to favorite popular music styles . With Classical music the 11L won't do justice to anything larger than a String Quartet or a reduced dynamics solo piano piece . sorry , Chris .