The test conditions in Harman's room are different from the set-up conditions of "typical listening rooms". Whether or not these differences matter is subject to debate. I'm of the (apparently minority) opinion that they do matter.
For one thing, the abnormally-long lateral reflection paths result in the first sidewall reflections arriving significantly later than they would in a normal room. My understanding is that the arrival time and intensity of the first lateral reflections play a role in both perceived sound quality and perceived spatial quality, and the Harman test conditions increase the arrival time and reduce the intensity of these reflections relative to a "typical listening room" situation.
I'm not saying this makes a big difference, but in my opinion it does make a worth-paying-attention-to difference.
However IMO the main question here is whether or not listening to the same loudspeakers in different listening rooms could change relative preference (and if so - in which cases and how?), not whether room characteristics matter / influence sound reproduction itself (they do).
In other words, can we assume that the same relative loudspeaker preference observed in a specific room is valid for any room? The
only article I know on this topic suggests that the room has an insignificant effect on relative loudspeaker preference:
The preferred sound quality of three loudspeakers was rated by listeners within four domestic-sized rooms. Evaluations of binaural recordings/reproductions of the same loudspeaker/room combinations were also made. Both live and binaural measurements showed the room had statistically insignificant effects on listener loudspeaker preferences. In a second binaural experiment each loudspeaker was compared among the rooms. In contrast, the room was the main significant effect on listener preferences, while the loudspeaker was not significant. These contrasts in loudspeaker and room effects indicate that subjective measurements of sound quality are relative measurements strongly biased by the context in which the measured objects are compared.
On the other hand, I can easily imagine cases where preference might be influenced - e.g. a good wide dispersion loudspeaker might be preferred in a room with reflective side walls vs a good narrow dispersion loudspeaker, but this advantage might also be lost in another room where side reflections are absorbed, making the two loudspeakers sound more similar.
What would happen if the wide dispersion loudspeaker has uneven directivity and poor on-axis response and the narrow directivity one had even directivity and flat on-axis - would its wide directivity still give the former a chance in some rooms?
Is there any research showing such effects?
From the picture it does look different, and it surely does affect sound, and will also favor some speakers over others, compared to how they perform in a more typical listening room.
I of course agree that the Harman test room will 'sound different' than most other rooms (since most rooms will sound somewhat different to each other), but can you provide some references to back the claim that this can impact relative loudspeaker preference in listeners under controlled conditions (i.e. some loudspeakers being consistently favored in some rooms)? Thanks!
I doubt the test room will reflect 99.9% of the real world room.
Note that the test room doesn't really need to represent 'real world rooms' if the room is an insignificant factor in listener loudspeaker preferences.