Well folks, for what it`s worth I`ve read through this whole post/thread, and thought to add my experience in "voicing" , as it`s called on a lot of sound systems, both PA`s and playback, both home and a few recording studio`s control rooms starting back in 1978 using HQ 1/3 octave equalizers where available after buying and reading Don & Carolyn Davice`s Sound System Engineering Book.
And realized back in 1975 when first purchased the book and understanding the benefits of EQ in "smoothing" out the irregularities in acoustic response of the "properly designed and setup audio system, but had to wait until 1978 to be able to afford my first RTA.
I and about 98 % of the people, customers/clients agreed that the resultant SQ was much better sounding(though some people like the colored bass room nodes, and don`t like it tuned/voiced out !) when properly gain matched(via the EQ`s level control/s when switching between EQ & no EQ, as all EQ correction was always cut and never boosted, and often during the initial tuning/voicing it was found moving the speakers, sometimes just slightly, helped reduce room modes & nodes.
For maximum benefit from the voicing, the sound system had to already be able to sound as best as it`s speaker/s quality and room placement would allow, as proper voicing of a well designed and implemented of a audio system can be considered "the icing" on a properly baked cake, at least, that was my take on it, and I never tried to voice flat, but followed the natural roll off of the end`s of the bandwidth of the speakers being EQ`d for the smoothest and most pleasing sound
When I was employed for two years as a 6 night a week FOH Sound engineer on a 3 month 3 club rotation, and I was told many times, my cobbled together ,3 way bi-amped PA, sounded more like a loud clean stereo with very good SQ, that was consistent from club to club, even though radically different room dimensions, stages, room treatment(acoustics, or lack thereof).
I also had a 1/3rd octave voiced stereo bi-amp`d system in my apartment at the same time and could readily demonstrate the benefit's of a voiced playback system to clients who were interested in taming their playback system/s frequency response, usually the bands below 500 Hertz showed the most noticeable improvement in most voicing applications..
I was able to make enough money providing this service to be able to upgrade my crude Shure RTA to a IVIE IE31A class 1 analyzer & pink/white noise generator in 1980, @ a cost of $ 3,500.00 !, but it reduced my audio system voicing time, by at least half, so it started paying for it`s self pretty quickly, as most of the other local bands, if engaged for a length of time, or were a house band could justify the $ 50.00 that I was charging for voicing their PA, plus they often were not aware of problems in their system that I discovered prior to voicing(remember must be a properly baked cake before the icing is applied !)
One of the benefits of voicing a playback system, was afterwards, any personal tonal voicing desired by the user of the system was easily handled by any mild use of available system tone controls to overcome varying music recording/production tonal differences, if desired, as their use seem to be more effective with less amount of control adjustment than before voicing the system.
Now for my own personal tastes in playback voicing is to EQ it as smooth as possible and playback known HQ SACD/DDD CD`s and mildly adjust any 1/3rd octave sliders, if needed to make it more to what I might like, and then leave it alone.
I then accept that not all my music will sound as good as those reference, to me recordings and just accept the great, good, and not the best effort of some earlier recordings, and won`t chase them with tone control adjustment.
I originally manually 1/3rd octave voiced my Mac tri-amped living room`s system in 2003, after getting the system to sound the best I could before hand, and it took me all day with (7) 1/3rd equalizers to less than +/-2 db, and was so damn glad to upgrade latter on to a HQ electronic crossover(now called loudspeaker management that self electronically aligned both phase and distance the highs to the mids, and then align those to the separate bass cabinet.
And then I purchased the Integra A/VP with it`s Audessy capability, in which I love it`s DSP super fractional octave and time alignment for the best sound quality that I have heard with my speaker room combination so far in the nearly 30 years that I lived in this house, and I`ve never felt the need to adjust any tone controls(in fact, I have never bothered to try to find out in the menu for accessing the ability to do so ) for various music selections, whether WAV; CD, BluRay Pure Audio, SCAD, etc. sources
I, and others, prefer the smooth tonal balance of a properly voiced sound system.
However, to each their own.
Anyway, sorry about this long winded diatribe folks.
Carry on and enjoy your music as you see fit.
Kind regards, OKB