Predicting Array Performance: Hanging The PA Right The First Time

Once the room is built, there are a couple of ways to drop the sound system into the model. There is a library function where you can store all of the cabinet models you are carrying. The speaker locations are chosen by using simple X-Y-Z coordinates. You can build a cluster one cabinet at a time or use pre-designed blocks of speakers that you have defined as clusters.

If you build the array with individual boxes you can change the pitch, roll and azimuth of each box independently. If you build with clusters you must change parameters for the whole unit. Each box or cluster can also be adjusted for output volume and delay.

A chart is generated showing the exact location, height, tilt, volume and delay parameters for each box or cluster. This makes it a snap to put everything where and how it was modeled.

The program generates a color SPL map of the room at chosen frequencies. Audience surfaces can be chosen so that the model only shows coverage where the people are. Or we can look at all surfaces so that sound can be steered away from non-audience areas to minimize the system’s interaction with the room. Individual cabinets or clusters can be turned on or off to see what contribution to the overall coverage is being provided by them.

In addition to SPL maps, the program will provide complex summation maps. These show the constructive and destructive interference patterns that are produced by overlapping coverage patterns. This enables you to see comb filters and the lobing they produce.

These types of tools keep coming along to make our jobs more complicated in some ways but simpler in others. And if we can hang the PA right the first time, we can spend our day tuning, tweaking and sound checking. But the bottom line is better sounding shows with more even coverage through the whole venue.

And that’s what it’s all about, isn’t it? Besides, all this computer modeling will keep us out of the back room on the bus!