Does placing PA speakers up against a hard-surfaced ceiling (see attached photo "close-up of main speaker”) cut some of the higher frequencies (5kHz and up)?
Reason I’m asking is my church had the ceiling tiles in the main auditorium over-laid with plastic decorative tiles (see attached photo "church and main speakers”) and ever since then both of my EAW fr129z main PA speakers aren’t as clear in the higher frequencies as they use to be. These speakers have always been up against the ceiling, ever since I took over sound at my church.
I did some measuring with SMAART and saw a downward cut in the 5kHz range, as if I had placed a Low Pass Filter at 6kHz. I tried fixing this issue with a parametric EQ by using a high-shelf gain increase at 6kHz to fill in the downward cut. Although this made the EQ flat in the 5kHz - 20kHz frequencies, I sometimes I get loud ringing sounds in those areas.
Is EQ the only way to fix this problem? What would you guys suggest?