I am also not sure what to think about it, but on the other hand we must also show the argumentation of Toole:
"I guess you have to experience it to believe it. I did my first stereo vs mono test in 1985 and it was a very thorough and carefully conducted blind test. All of this is in JAES papers and in both books, so I won't get into regurgitating old research. The amazing reality is that listeners reported extensively on spatial/soundstage characteristics when listening in mono - which everyone, myself included, thought would be commented on only in stereo. The spatial ratings in mono closely tracked the sound quality ratings, and both were more strongly differentiated in mono than in stereo listening. We have learned since then that sound quality and spatial quality are closely linked.
In mono, the highest rated loudspeakers came closest to "disappearing" behind the screen, leaving impressions of image size and distance/depth to information in the recordings. Because stereo is mono L, mono R and double-mono amplitude and/or delay panned phantom images (including of course the featured artist), it is understandable that the soundstage is improved if one's attention is not drawn to the loudspeakers. This tends to be an advantage for wide dispersion loudspeakers. It was interesting to see that the mono ratings agreed with stereo ratings for close miked, pan potted stereo pop (truly multiple mono). With more complex pop and classical music there is a huge amount of uncorrelated information in both channels (to generate the desired spaciousness) and the spatial/soundstage ratings were not strongly differentiated. The dominant factor in the stereo tests was the recording itself, which, if you know how the signals are captured and processed, is not surprising. These are control room creations.
Over the years we have done a few stereo vs. mono tests to convince skeptics with the same result: the highest rated loudspeakers in mono, have been the highest rated loudspeakers in stereo but the differentiation in stereo was not always as easily discerned. Highly directional loudspeakers tend to stand out as lacking in both stereo and mono. Recently, the comparison has been expanded to multichannel, and it is even more forgiving than stereo. The more channels that are
simultaneously active, the less the room interactions can be heard. But we listen in mono much of the time, in multi-mono stereo in non-classical music, a dominant center channel in movies and any time a signal is hard panned to a single channel. So how a loudspeaker sounds in mono matters, and mono tests yield the most critical comments. In stereo expect a speaker to be no worse, possibly better, but the stereo soundstage is definitely engaging."
Source:
https://www.avsforum.com/forum/89-s...viewed-speakers-ever-made-8.html#post54603712
and his comment on this image:
View attachment 75071
"If you look at the scatter of individual responses it is clear that there were random differences of opinion. Do a little math and it will be clear that the differences in the stereo tests are not statistically significant. These were averages for all programs, and program is a variable - more obvious in stereo than in mono. Bear in mind that these tests were done by me in 1985 - 32 years ago. I know of no other tests of comparable thoroughness and published in a refereed journal since then. It may or may not have been flawless, but it remains the best evidence to date.
Toole, F. E. (1985). “Subjective measurements of loudspeaker sound quality and listener preferences”, J. Audio Eng. Soc., 33. pp. 2-31.
Toole, F. E. (1986). “Loudspeaker measurements and their relationship to listener preferences”, J. Audio Eng. Soc., 34, pt.1, pp. 227-235, pt. 2, pp. 323-348.
This is not just my opinion. Evans et al. (2009 ) reviewed several studies examining the effects of loudspeaker directivity, concluding that there were several fundamental questions remaining to beproperly investigated. They did note that the author’s work described here “appears to be the most relevant to date, with regard to loudspeaker directivity effects.”
Evans, W., Dyreby, J., Bech, S., Zielinski, S. and Rumsey, R. (2009). “Effects of loudspeaker directivity on perceived sound quality – a review of existing studies”, Audio Eng. Soc., 126th Convention, paper 7745.
Most people don't have the facilities, the money, the time, or the attention span, to undertake such meticulous tests. Nevertheless, since then there has been a never ending stream of unsubstantiated opinion from all possible quarters. But that is audio.
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Progress is slow, but there has been progress. A major problem is that enthusiasts in general have not taken the trouble to find and read the existing science. They will not be guided to it by audiophile publications because for many of them the scientific findings run contrary to their business interests. Fortunately a few have acknowledged that the complete answers may not lie in "take it home and listen to it" sighted and biased subjective evaluations. But for them the lack of facilities and finance are serious limitations. So, in the absence of published comprehensive anechoic data, consumers and professionals are seriously handicapped when trying to make rational decisions.
The last chapter in my new book is a 50 year retrospective on loudspeakers - lots of curves. It is clear that there were some excellent loudspeakers years ago, and some mediocre ones even today. Price is not a factor. Professionals seem to have had the greatest problems embracing measurements. Several consumer audio magazines show measurements in their reviews - not perfect, but usefully accurate, and in one case (soundstagenetwork.com) nearly so as they use my old NRCC facilities. Professional magazines almost always leave evaluations of monitor loudspeakers to sighted listening tests by individuals who have a high probability of having hearing loss. Go figure."
Source:
https://www.avsforum.com/forum/89-s...iewed-speakers-ever-made-10.html#post54613648