Are you still refusing to evaluate speakers in pairs? I continue to maintain those sort of subjective evaluations are meaningless and not useful to the consumer.
On the point of mono vs stereo listening, , like Amir, I also measure and create Spinoramas (with less accuracy/resolution of course). I also listen in mono during evaluations, but I mostly listen in stereo because I use the speakers in my primary listening room setup. Usually it's at least a month, some it's more.
Though I am nowhere near Amir's pace, after a couple of dozen speakers, listening in stereo has
almost never revealed something I could not glean from mono listening.
There are a few exceptions:
- Egregiously bad pair matching, a relative rarity these days. More common with ultra-budget speakers but even then rare to actually
notice in stereo listening.
Ironically, it's easier to detect by listening to both speakers separately in mono. The time I noticed the worst pair matching, one of the speaker's dome tweeter had been pushed in, and I noticed the speakers sounded a bit 'dull' and perhaps slight asymmetrical, but it was mono listening and later measurements that clearly revealed the issue.
-Wireless speaker syncing: For wireless speakers, stereo is necessary to make sure the wireless connection is actually solid. Unfortunately, this is sometimes still not the case.
-Offset drivers: Speakers with offset, mirrored drivers will sound different depending on whether the tweeter is on the inside or outside edge of the speaker. It's harder to relate spatial presentation in mono to stereo for offset drivers in my experience.
-Stereo listening leads into a perceptual dip around 2kHz for the phantom center(Interaural crosstalk cancellation). Usually not a huge deal in a typically reflective environment, but it's a slight difference in tonality.
But far more important than these exceptions, in my opinion, is that listening in mono often reveals things that are much obscured in stereo without extended critical listening. An hour of mono listening feels like it tells me a few days worth of stereo listening. You get
way more bang for your buck listening in mono when evaluating a speaker's flaws.
To make an exaggerated analogy, suggesting Amir should place the same or more weight on stereo listening is like suggesting a photographer should evaluate a camera's performance based on how the photos look on a smartphone after an instagram filter or two. That's how most consumers will see the photos, but it's not the best way to isolate performance issues.
Similarly, the net effect of stereo listening is making a speaker sound better, as per harman's research and my own experience. It does little to improve ones ability to critically evaluate a speaker.
Both is obviously better than just mono, but mono listening is very much more efficient than stereo. And at Amir's pace, it doesn't make sense to do otherwise imo.