The tests have been done, by educated, paid, professional, experienced researchers who do audio research for a living, and publish their results and compare to other researchers who publish their results. The conclusion is, that speakers that perform well in mono tests also perform well in stereo tests. And that when tests are done in stereo, the results are not different, and do not change, when compared to results obtained when testing in mono. You don’t have to wonder. The good news is that stereo testing has been considered, empirically evaluauted, and found to not give any advantage over mono testing.
Howdy, these are some pretty large definitive claims, prolly better back them up with links rather than nods to professionalism.
I surely understand why Mono was chosen - or at least why I would use it. Relative Simplicity. Especially when speakers are to be used in any number of multichannel from 2-20.
Listening in Mono and conducting a double blind controlled testing on a large number of subjects in order to study a wide variety of sound reproduction traits is already a staggering task. Going beyond mono complicates this in unbelievable ways. (think 3 body problem)
Mono is a good way to ensure that the study is mangeable at best. I can also see how generally speaking a speaker that sounds great alone ought to sound great in stereo or multichannel and I beleive Toole that he did test this enough to feel comfortable sticking with mono.
That said it seems there has been only a little published on the effects of stereo reproduction, nothing like the large mono studies we refer to here at ASR.
I have read Toole's book and he only touches on the subject now and then.
The results of the limited tests I have seen published
did change in stereo vs mono, it was not a linear increase. In my view your claim that they did not is false. However Toole is clear that the winner still won but typically by less. Section 3.4
I think this is important as it pertains to how the completed system sounds which as a consumer is what I will be actually using. Some speakers will be much less enjoyable in mono vs stereo and others will actaully not improve as much going from mono to stereo. Interesting stuff.
Why they changed did not seem to me to be able at the time to be deeply investigated (& understandbly so)
Additionally the speakers were not always able to placed in optimized positions based on the individual speaker nor were all listeners always in an optimized seating position. Dispersion alone is a huge factor if the speaker's position is not optimized or even if it is if the listener is off axis and or the dispersion is narrow vs wide. Playback SPL is a factor as the tonality is not perceived as increasing in a linear fashion as the volume goes up or down. Which can really affect bass and as bass is some 30ish% of perceived SQ then that is big.
Age of listeners/hearing ability such as people who are actually confused by the stereo soundstage in the same way they would be in a crowded restarount.
This and more. Plus as you implied money is involved. At some point this has to make someone money in our society, it wasn't charity work. There was a budget and constaints and limited time and finacial goals involved. All understandable aspects of a complex study(multiple studies), and it is conceivable a lot could still be addressed in further investigation & certainly traits that were or were not issues in this study may present differently in a finished, known install.
However, it is interesting that Dr Toole's research shows that speaker preferences don't really vary with the type of music used, or the type of music that the listener is used to. If they did vary, then his book would have said "this is what you need to look for in a speaker for classical music, and this (different criteria) is what you need for pop/rock". Instead, his book actually mocks the whole idea.
The real issue is judging speakers blind and level matched. Which practically no-one does.
Section 3.5.1.7 is a basic discussion on program material.
In a nutshell it does matter what program material is chosen for conducting accurate, repeatable testing.
and
@sejarzo figure 3.15 & 3.16 in Toole book may be helpful as well as the summary that," complex productions with broadband, relatively constant spectra aid listeners in finding problems". He also says there are no hard and fast rules.
He mentions in section 3.4 that imaging(and thus listner preference) in particular is very different from say classical(lots of recorded ambiance) on a narrow or wide dispersion speaker. Or Jazz with lots of close miking and hard panning(highly controlled manufactured soundstage stage without real ambiance). This difference is true in mono and stereo.
At any rate I highly doubt that some specific music track or whole album(track not, genre) doesn't present better on some speakers vs others.
The circle of confusion almost requires it and this would require a decision to be made about testing that may or may not satisfy all.
That said,(sighted listening) within a reasonable range of variation my favorite speakers generally sound excellent on nearly everything I like and the worst ones I have heard tend to sound fairly bad often with a few tracks that seem to hit just right. (and a big lot of tracks where it is not really easy to form a solid preference)
