when I am in a totally different room, I often find that the physicality is there on those bigger systems. But would your reflections analysis still hold in those cases? I would have guessed once you're in a different room and find that the system has that sense of physical power/presence that simulates real instruments...it is more about pure air movement than the reflections?
I'm not sure what you mean... are you talking about comparing a small system in a small room with a bigger system in a "totally different" - bigger? - room?
Imo the room (including speaker set-up and listener location) gets a vote, and the speakers themselves get a vote.
At the risk of over-generalizing: A bigger system will usually be doing more things right than a smaller system, both in the direct sound and in the reflection field; it will usually have deeper bass which contributes to the sense of being an a three-dimensional space and witnessing a three-dimensional event; and it will usually have a higher direct-to-reflected sound ratio. If it is also in a bigger room, the reflection path lengths (and therefore the time gap before the strong onset of reflections) will be longer.
There is a "poor man's hack" for getting some of these benefits with a relatively modest system in a smaller room: Position the speakers further out into the room, closer together than normal, and then sit closer to them than normal so that your stereo triangle is preserved. This increases the direct-to-reflected sound ratio and increases the reflection path lengths relative to a more traditional set-up configuration.
If fact even without moving the speakers one can just try scooting the listening chair closer than normal, maybe adjusting speaker toe-in if needed. In my experience there will often be a distance at which the perception of "physicality" or "proximity" or whatever is suddenly there, but then it is not there if you are just a few inches further away. I think there is a perceptual threshold that is crossed.
Of course this sort of "quasi-nearfield" setup results in the speakers dominating the room moreso that may be feasible, and it's pretty much optimized for one-person-only listening.
As I said, I’m sure there are a number of factors that go into our sense of “physicality” so I’m not attributing it wholly to air-pressure. My concern was: (1) to argue that this sense is not an illusion but has a basis in a real, potentially measurable, acoustic phenomenon
Agreed, it's not an illusion... well I guess in a sense it is, in the same sene that stereo itself is a spatial illusion, but ime "physicality" is a
real spatial illusion instead of a "wishful-thinking" spatial illusion.
; and (2) that different techniques in speaker design more or less correspond to the degree of this sense of physicality.
Agreed.
Now as
@Ron Resnick pointed out, "physicality" is something the omnidirectional MBLs can do, but the specific room set-up conditions (including room size) play a significant role. One area where the MBLs excel is this: Their off-axis sound starts out with
exactly the same spectral balance as their direct sound, so the spectral balance of their reflections is effectively perfect, assuming the room doesn't absorb too much of the high frequency energy in the reflections.
Imo this "getting the reflections right" aspect is a significant contributor to the ability of the MBLs to create the perception of "physicality" under good set-up conditions.
Incidentally, on the subject of direct versus reflected sound as a factor in “physicality”, I use a Trinnov ST2 Pro Optimizer to control these and other electronically modifiable methods of transforming the sound in the room. For instance, I can change the direct/reflected ratio to approach anechoic-chamber level. And I do find that the sense of “physicality” is increased the closer I get to direct rather than reflected sound from the speaker/room interaction.
Very interesting!
Can you describe how the Trinnov changes the direct/reflected ratio? Does it generate cancellation signals which cancel out the reflections at the microphone location?
If so, which reflections does it cancel? "Approach[ing] anechoic-chamber level" is pretty impressive!
