Originally Posted by Roger Dressler
But I see no problem getting solid out-of-head images with real speakers placed out front, if the speakers are up to it and the room cooperates.
Anyway, with all the variables involved, not the least of which is taste, I think any such hard recommendations must be tempered with user experience/preference.
Well, I'm not interested in taste, I'm interested in the technical and psychoacoustic fundamentals of minimizing the inherent problems of the stereo-system - how to fool the brain the best to think sound arriving from two points of radiation to sound the same as it would be from a singular source placed elsewhere. H(T)RTF is a huge part of that 'magic' and even though we do have individual variations, the statistic data shows the variance to be within a useful range. Depending on where on the curve you want to do the cutoff, you get 21-23, possibly 25 degrees. NHT had the 21 degree built into them originally, if you remember say the wonderful monolith named 3.3?
I for sure can accept that some speaker/room combinations may have less problems with non-optimal placement, but I don't see that they wouldn't play even better in optimum placement unless there's some other flaw with their frequency response or radiation pattern. I assume they don't in discussions like this, though. In that case I'd rather recommend change of speakers before proceeding.