Hi all,
Yes, do tilt downwards if you are using the Axiom ceiling-mount brackets for the QS8s. The 6-inch breathing-room suggestion for the QS8 top-firing woofer is just a guestimate on my part for those who are wall-mounting the QS8s, as in "Don't put them too close to the ceiling. . ."
As to the QS8 stand design, the height chosen is a trade-off between stability (any taller and they'd be very tippy) and performance. They do sound fine at the QS8 stand height, as CV attests. I've found that if you have the choice, wall-mounting the QS8s up higher tends to make the surround field a little more realistic, mostly for airplane/helicopter fly-over effects from movie soundtracks. You hear those effects above you more.
Regards,
