I probably won't use the right verbiage but the issue stems from BYU not owning the air rights north of the stadium in the residential areas. There's a city code (implemented after complaints from residents) that the music was too loud. Now the noise pumped from the stadium cannot exceed a certain decibel level. The speakers are positioned to send the sounds wave southward as to not exceed the decibel threashold in the north stadium residential area.
Sounds like its time for these old farts to move out of their houses and let some real Cougar fans move in.
PS, this is also the reason the proposed 100' video board never came to fruition. They complained that the shadow cast would prevent the snow and ice from melting on the road just north of the stadium.