The Ascend Sierra-2 uses the RAAL ribbon tweeter which is very good. Monitor Audio doesn't list their tolerance for the frequency response, so the 42Hz they claim doesn't tell you much. The Sierra-2 extends down to 41Hz at -3dB. You could order a pair of the Sierra-2 and see what you think, they have a 30 day trial and all you would pay is return shipping if you send them back.
Denon AVR-1713 | EMP E55Ti | EMP E56Ci | EMP E5Bi | BIC F-12