MikroTik Audience slow speed WiFi, why?

http://forum.mikrotik.com/t/best-wi-fi-coverage-with-single-router-audience-ac3-chateau/139432/1

“Audience should have the best coverage, also the design is more upright and from personal experience, covers really large areas.”

But If the best device is acting so bad and needs also tuning, to get it somehow work at all, then this is insane.