If you don't have a wide sweet spot, are you really an audiophile?

That Japanese science thing is very similar to what I have heard from years ago and what Duke has talked about as well. 

Image focus comes almost entirely from the direct sound. Reflected sound affects this differently depending on the amount of delay. Within a window of about 3-5ms it is too close in time and imaging suffers. Sound travels about 1ft/ms. This is where the advice to place speakers several feet from walls comes from. Beyond about 5ms reflected sounds contribute to a perception of space. This is where the sense of envelopment comes from. 

That is of course far from the whole story. That is just one aspect of it. The initial wave front. Really accurate low bass is associated with large spaces and is another factor in envelopment. Then there is the spectrum of direct sound to the reflected, diffuse sound. And more. They all go together. 

These are all closely related and similar. There is more difference in the language being used to describe them and from what point of view than anything else.

djones51-

I’ve never understood what Mahgister was talking about, especially concerning timbre.

I’ll give my layman version, timbre is how I can tell a trumpet from a clarinet playing the same notes.

Right. We don’t even need a fancy audiophile definition for timbre the regular dictionary one is plenty good enough:

the character or quality of a musical sound or voice as distinct from its pitch and intensity.

The character or quality we are talking about is what distinguishes a violin from a viola, alto sax from tenor, flute from piccolo. Even when both are playing the same note at the same volume. Because that note is never a pure tone, it is always a complex combination of harmonic overtones. The particular way the relative values of all those harmonics combine is timbre.

What acoustic embedding has to do with it I don’t know I don’t even know what acoustic embedding even is much less the other two though I have tried to figure out what he’s talking about.

Okay well the way I read mahgister is embedding is just another way of saying tune or control. Helmholtz resonators for example are one sort of acoustic control. Air pressure goes through an opening, in a bottle or straw, into a space, and back out again. In the process of going through the restriction it gives up energy. So a Helmholtz resonator is like a shock absorber. In reality it is just another sort of tube trap. It is also fundamentally the same or related to porting in a speaker cabinet. All the same sort of thing.

Your room, any room, has it’s own particular set of resonant frequencies. Why do you think it is so many people have the same bass problems in the same areas? Because the rooms are so similar in dimension. The helmholtz resonator can be tuned by its size and shape to damp these room resonance modes.

Okay so now take a look at what we have so far: timbre is the exact combination of harmonics that tell us which instrument is which. Room resonances affect different frequencies differently. Therefore, controlling them will help reproduce timbre accurately, making each instrument sound more like it should.

Replace "controlling" with "embedding" and you got it. Same for the other two embeddings, vibration and fields. Got it?