Elliot, of course I would not say that the flattest sounding speaker would be the “best” or more relevant, my preferred speaker. There are several lengthy reasons for this, but to discuss these is to miss the point of my remark. What I am saying is that frequency response, more than just about any other single physical parameter, is key in determining whether a speaker sounds pleasing to me. Furthermore, I would argue that is true not just for me, but to the majority of listeners. A landmark paper by Henning Moller of B&K Instruments, Inc., that was presented at the Copenhagen AES in 1974, sheds some very insightful light on the preferred frequency response of loudspeaker systems at the listening position by experienced listeners. The entire paper is presented here:
http://www.bksv.com/doc/17-197.pdf
One key point, and one that I seem to agree with, is that a flat frequency response is not the most commonly preferred response. Rather a very slight attenuation from low to high frequencies is what sounded best. Actually to be accurate, they said, “When music is recorded under far-field conditions, it will contain a suitable mixture of direct and reflected sound, and the curve ought to be absolutely flat in that case.” “However, since most recordings are made as a combination of near-field and far-field information, the curve should boost a little at low frequencies and roll off a little at high frequencies. A suitably shaped curve is shown in Fig.5.”
For those that don’t want to read the entire article, which is a beautiful and serious early study of human psychoacoustics as it applies to listening to loudspeakers, the key figure being discussed can be found here.
http://www.whatsbestforum.com/showthread.php?723-Target-Curves
Does this mean the B&K curve is “right’ and all others are “wrong”. Of course not. It’s just a preference, and it is one that I have found, in general, to agree with. There are surely others who find such a frequency response curve equally compelling. For example, Jason Bloom of Apogee sought to have his speakers register at the listening position with a basically flat curve from 100-10K that contained a slight top end roll off above 10K, and a 2-4 dB bump from 30-80 Hz (the so called “Bloom Bump”). This then, roughly approximates the B&K curve.
Most of the basis of my preference comes from experimenting for many years with DSP in my system. It is certainly possible that with other components besides the ones I currently use, I might have slightly different preferences. But I think its fair to say that based on my experience I find the B&K response at the listening position one that I generally prefer. Is the frequency response alone the basis of a singular preference? Most likely it is not. But if you had to pick one, certainly frequency response, perhaps followed closely by distortion, are the leading two physical parameters that count a great deal towards determining if speakers sound good, at least to me.
As far as REG’s sound room, I can’t speak to that. I do however find him to be someone who speaks for the most part with a good deal of common sense on matters audio, although he and I are not without some sonic disagreements. For example, he loves Harbeth 40.1 loudspeakers and while I find them pleasant, I am not wild about them. I on the other hand, like the sound of Maggie 1.7 and 3.7s yet he has little to say about these that may be interpreted as high praise. Is this due strictly to differences of frequency response? Probably not. So be it.
If I interpret your challenge correctly, I do not in fact, think speakers of different design would necessarily sound the same if they had the identical frequency response (whether flat of “B&K”). Most importnatly, as we have said, distortion would be a physical parameter that would also come in to play, as would a host of other things (dynamics, S/N, timing and phase angle of the drivers, radiation patterns (as Jeff Fritz correctly notes), power distribution etc.). But I think it’s fair to say this. Speakers with similar frequency responses are likely to be judged similarly as ones that are sonically pleasing, or not. Show me something with a “B&K type” response at the listening position, and there’s is a good chance I will have a favorable reaction. Show me something that is flat from 20-20K and my sense is that I probably will have some objection to the sound based on frequency response because the top end might sound too hot. Again for me, an exaggerated top end or one that is not gently rolled off is a common flaw in many systems that leaves me nonplussed as it does others such as REG, and as I suspect, many audiophiles. All of which is to say very little other than this is obviously an issue of personal preferences. I think Russ summarized that equally well in post #128.