"Any electrical filter on an acoustical device is a spatially invariant solution to a spatially variant problem. As grownups we have to decide what part of the space to tune the solution to and let the others go." -Bob McCarthy
I wanted to post this here so I wouldn't forget it.
If you're not into audio nerdery, you're probably wondering what this means. My personal interpretation of this is as follows:
Your friendly, neighborhood audio technician has a responsibility to deploy the PA system at their disposal in some environment. Inside, outside, whatever. That environment has acoustical properties, and the PA has acoustical properties too. Us PA guys most often use equalization (electronic filters) to make the PA system sound good in the environment where we've got it set up, but that's only a patch on any problems that exist. It's entirely possible for that patch to be very good, but it's still just a patch. It is not truly possible to solve an acoustical problem with an electronic solution. To truly solve an acoustical problem, you have to change the room, or change the PA deployment, or both. However, that's usually not possible, so a professional PA operator needs to decide what compromise will work best for the situation at hand, and go with it.
I don't know if the above is truly in line with Mr. McCarthy's original intent for this quote, but I think that it does fit. (My belief is that Mr. McCarthy is really getting at the issue of not being able to have "perfect" sound everywhere in a performance venue, but I think there are wider implications as well.)