Re: Frequency Response/Contour EQ in full range systems.
This thread has been as enlightening and fun as the best the old PSW forum had to offer - thanks to all who've participated. 
To summarize, Helge asked what he probably thought was an innocent question about biasing a PA's frequency spectrum to something other than flat. My take on the implication is that once biased, the majority of musical sources would require a minimum amount of channel EQ from the FOH console to achieve the best subjective result. Benefits would include a quicker/easier FOH soundcheck as well as a better end result from time and/or skill challenged operators.
Measurement systems and their various time and frequency windows got honorable mentions as needed - how can we objectively communicate or create repeatable results without measurements?
An Observation:
A guy named John Murray posted on the SAC list in June 2004 that Japan's TOA engineers taught him how to flatten the phase response of a loudspeaker using all-pass filters. His post was a mistake because I stalked him with emails and phone calls to tell me how to do it until he relented. In one of my conversations with him he mentioned how he was able to EQ a PA so that it sounded good with TEF (generally excludes later arrivals from the room), but was never as happy with the results he got when using Smaart (generally includes later arrivals from the room). I was quite happy with the results I got with Smaart but wasn't able to do consistently as well with my other system at the time - MLSSA.
A Thought:
It took me about 5 years and thousands of measurements to figure this out, but your brain can largely compensate for the weaknesses of your measurement platform! You look, you listen, you learn.
I now use three measurement systems regularly in their specific areas of strength. I know how to get the same results across all platforms in most situations, but I've found that near-anechoic responses at mid and high frequencies with near-RTA responses below that are most helpful in system tuning. The polar patterns of things that make sound, ensuing environmental effects and the human perception of that soup nicely explained by Phil led to the development of the decimation and/or multiple windowing techniques available in Smaart, SysTune, ARTA, SIM, MLSSA, Praxis and probably others.
