This is way above my league (my whole system cost $5000), but it strikes me that if you're completely happy with the Quads except for the bass and sense of scale of the sound then you should try to get a home demo of a good quality subwoofer, like a higher end REL, or audio-physic.
I was in the same situation with my system (based around spica-angelus, which have fabulous midrange and imaging, but can sound a little thin and lacking in dynamics) and the addition of a REL sub completely fixed my system. Now orchestras sound like orchestras.
It's worth a try before swapping speakers, and would probably cost you around $3k for a good sub.
I was in the same situation with my system (based around spica-angelus, which have fabulous midrange and imaging, but can sound a little thin and lacking in dynamics) and the addition of a REL sub completely fixed my system. Now orchestras sound like orchestras.
It's worth a try before swapping speakers, and would probably cost you around $3k for a good sub.