Prior to the digital revolution, PA processing equipment was expensive and without proper tools to measure the results, there was little purpose in more than having system EQ.
With the advent of tools like SIM and then SMAART combined with inexpensive DSP (digital signal processing), we moved from the stone age of live audio into the present.
Today the average sound company can afford many of the same tools that were previously available only to the largest sound companies.
My first “DSP” was a dbx Driverack 260. (2) inputs / (6) outputs. Cost was around $1000 new. Today that device seems rather crude but it still works and still provides a lot of options if I need it. Time has leveled the playing field to a great degree. If I really wanted a fair playing field, I’d need something like a Lake or Meyer Galileo. Still too expensive for most of us but the playing field continues to become more level.
The basic tools we need for PA processing are parametric EQ (for complimentary equalization), delay (for time aligning our sound sources) and compression / leveling (for dynamic control and component protection).
Current audio DSP options allow for things like wireless control via a PC tablet or Ipad. You can spend as little as a few hundred dollars and as much as a few thousand dollars for a device that does basically the same thing. The point is that DSP has made PA processing available to the masses at an affordable price. None of this helps us time align a PA system, know how to tune a PA or aim speakers correctly. Those tasks are best tackled with a different tool set. An audio measurement rig. When you use the two together you can achieve a level of accuracy that is impossible when adjusting things by ear given the same amount of time.