"Jim Lesurf" wrote in message
...

But it brings me back to my main question, which I've left unsnipped
above.
I am wondering if others have already experimented and formed a view wrt
what kind of alteration may be systematically beneficial for various
classes of material?

Most of the work that you describe, namely equalizing audio feeds to improve
their listenability, is one of the canonical functions of live sound mixers,
of which I am one. I mix about 4 hours a week of live performances with
120-300 people in the audience. I serve at another 2-4 hours of full-staff
rehearsals per week. I generally work with about 32 concurrent active
sources, mostly microphones and electric instruments on direct boxes, and
with 2-4 channels of digital media players (audio and video).

There is no active channel of my primary tool, a Yamaha 02R96 that is set
for perfectly flat response. Not including the tails of end-of-band
roll-offs, some channels get the full +/- 18 dB capability of its 5-channel
parametric equalizers. I've been known to cascade equalizers in order to
increase range and sharpen response curves to deal with some particularly
tough situations.