Hello fireline and JohnK,
Yes, the titanium-dome tweeter with the 1-inch voice coil is now used in the QS4s, the same tweeter that is used in the QS8s and other Axiom speakers.
Ian Colquhoun, Axiom's president and designer, noted that the change was made "because the 1/2-inch voice-coil tweeter was only being used in the QS4 and that did not make sense from a manufacturing viewpoint. Sound and power handling are unchanged because the power capabilities are established by the woofer, not the tweeter. The new tweeter will not physically fit in the old cabinets so there is no possibility for changing them."
Regards,
