Country: USA Did a search first on this question. I got a gig doing a remote recording at a church, using a 4 mic rig, recording their band through their PA. Before recording, I had their sound man run a variety of tones through the room while I walked around and measured with a frequency analyzer. Measured using A weighting. 125Hz was incredibly uneven, at times bordering on complete Null in certain areas, while other areas registered up to 3 db jumps. I passed by one corner, and the 125Hz was very loud compared to the other corners, which were all 90. This particular corner was obtuse in angle. I measured the corner, it was 200 (angle = 20 degrees). Materials, by what I was told, was 3/4" drywall over wood studs filled with R19. The room dimension is 50' x 52' x 12'. Nothing was canted. There was one 12' run on 2 opposite facing walls that were parallel. The other walls were broken up by various soffets and construction design. Ceiling and Floor are parallel, broken up by apprx 100 chairs that sit on the floor Floor was covered with standard grade commercial carpet. There is no acoustic treatment in the room. Their PA speakers are mounted. They are actives, 12" and horn, 4 of them hung above their stage in a horizontal array, although upon inspection I saw that these were speakers designed to be placed vertically and they had them hung horizontally, spaced in a semi-arc, top of speakers are 9" from the ceiling. My question is regarding that corner, because it was projecting the highest amount of 125hz out of all the corners in the room. I measured standing 2-3' away from the corner. Here is a drawing of the corner: My question is this: I was always under the impression that tighter corners were the culprits in creating standing waves of low freq's. Can you explain to me how this wider angle is creating such a tremendous projector source for low end?