My main point is that describing your subjective perception of the sound you heard while wandering along a corridor not even in the room with the speaker is not a convincing way to convey to anyone else very much about the speaker.
I don't expect you to believe or accept any observation I make as having any meaning for you.
What hearing the speaker outside the room often conveys to
me (not to
you) is, an approximation of what its power response sounds like.
Of course it is theoretically possible for a speaker with normal directivity (radiation pattern generally narrowing as we go up in frequency) AND a tipped-up on-axis response to actually have a more balanced frequency response from outside the room. In this scenario, the radiation pattern + tipped-up on-axis response could presumably "average out" to something more balanced than what we hear in the room with the on-axis response dominating.
I do think this is an interesting phenomenon though, because we're all familiar with hearing music coming from the window and having a sense of whether it's live or not. I'd love to know more about what causes this and whether / to what extent it translates into in-room listening.
IF a speaker sounds good from the listening position, AND if that speaker also sounds similar (and similarly good) from outside the room with no line-of-sight to the speakers, the implication is that there is relatively little spectral discrepancy between the direct sound and the reflection field. Note that this may not be possible to evaluate from outside the room if the room is heavily damped.
Similarity between the timbres of the direct sound and the reflections is desirable from the standpoint of both sound quality and spatial quality. Floyd Toole on the subject: "... the subjective effect of [the in-room] reflections became more desirable if they exhibited timbre similar to the direct sound...
When the direct and delayed sounds are similar the localizations are more precise, and timbre is less degraded." (emphasis mine)
I think there may also be a reduction on long-term listening fatigue when the direct sound and the reflections are spectrally similar. Let me explain:
The ear/brain system is constantly analyzing incoming sounds in order to classify them as either "new" sounds or "reflections". If it's a reflection arriving within 40 milliseconds or so of the first arrival, then the "precedence effect" suppresses the reflection's directional cues, but the ear/brain system still picks up the loudness and timbral cues. I speculate that, beyond some threshold, the greater the spectral discrepancy between "new sounds" (the direct sound) and reflections, the harder the ear/brain system has to work to correctly identify the reflections as such, and if the discrepancy is large enough then, over time, this "increased CPU usage" can result in listening fatigue. I asked Floyd Toole about this on another forum and he said in effect that this hasn't been studied yet, but he didn't shoot it down. Here is his reply (emphasis mine):
"The precedence effect really boils down to the direct sound dominating localization. Perception of secondary images associated with delayed sounds (reflections in our context) defines the breakdown of the precedence effect.
When the precedence effect is functioning, we are aware only of the direct sound as far as localization is concerned, but later sounds can affect loudness and timbre. This is discussed in some detail in my book, starting in Section 7.6.4. It is very signal dependent.
"One of the factors known to cause delayed sounds to be more apparent is a difference in spectrum. So the perceptual inhibition (NOT masking)
of delayed sounds as just described is related to the spectral similarity of the direct and reflected sounds. Delayed sounds that are spectrally similar to the direct sound are most successfully inhibited, as far as localization is concerned. Nobody I am aware of has chased down the quantitative differences necessary to be useful in the context of sound reproduction. All that I can say is that
loudspeakers exhibiting "similar" direct and off-axis performance receive elevated sound quality ratings, while those misbehaving off axis do not. Those are also the speakers the have the fewest audible resonances, and that tend to "disappear" behind the screen in double-blind tests.
"Direct sound dominates in terms of sound quality as was shown in my early papers in 1985-86, and later
, and it is also dominant in terms of sound localization if it is not corrupted by spectrally dissimilar reflected sounds. Does it require more "CPU power" when off axis misbehavior exists? I can only speculate that if sound quality is degraded - which is evident in every program played - I can imagine that it would eventually become an annoyance, even if it is a subconscious one. This is where the science that I am aware of fades."
So spectral similarity between the direct sound and the reflections contributes to good sound quality and good imaging, and it
might contribute to long-term fatigue-free listening.
And what a speaker sounds like from outside the room, with no line-of-sight to the speakers, can be one way of evaluating the spectral balance of the reflection field largely independent of the direct sound.
In my opinion.