The warm lush sound that ultimately emanates from your speakers is often as much, if not more so, a function of your CD player or pre-amp than it is your speakers. To get that lushness that you want, you might seriously take a look at your electronics... are they (your CD player & amp/pre-amp) somewhat bright or thin sounding? What do you have in terms of electronics? SS or tube? If tube, what tubes do you have?
I am an older listener, I so not like any brightness at all (older ears seem more sensitive to brightness than younger ones...why? not sure ... but it is the case)... and I myself went on a quest for lush, rich but not bright sound in my system --- but it meant completely and systematically changing the whole line-up of components. Actually, at 4-8K for speakers, most speakers in that range will be, generally, whatever the signal fed to them will have them be.
The point? You may be looking in the wrong place for what you want... the electronics may be more critical than the speakers (or, at least, as critical).
