Hmm. I didn't realise that neutral was a controversial concept. Is there any data that defines "neutral"? It would possibly include a few zeroes and infinities to which a person well versed in the art of deflection would say "You can't have zero/infinity in the real world". This is no different from the well-known "Everything matters". A statement of the truth at one level, but of no practical use whatsoever.
Well, try this:
- given a choice between high distortion and zero distortion, neutral would be zero. If we can't get zero - blah blah there's no such thing etc. etc. - then we get as low as possible.
- given a choice between high noise and zero noise, neutral would be zero. If we can't get zero - blah blah there's no such thing etc. etc. - then we get as low as possible.
- given a choice between high stereo crosstalk and zero crosstalk, neutral would be zero. If we can't get zero - blah blah there's no such thing etc. etc. - then we get as low as possible.
- given a choice between poor cone control and perfect cone control, neutral would be perfect. If we can't get perfect - blah blah there's no such thing etc. etc. - then we get as close as possible.
etc. etc.
To those who mention the room's effects, well we hear the direct sound first and it would seem logical that any 'imaging' will be primarily defined by that.
Beyond that, the question is: if you think that imaging is not just a question of neutrality, then what is? This is what I would like to know! If there is something else, then what is the 'scientific' explanation for it? Just saying "Vinyl and valves image really well" doesn't offer an explanation of anything - and doesn't seem a very convincing assertion either.
I do not think anyone is arguing against "neutrality" in sound reproduction. We want that, as far as the idea goes. But, in common semantic use in audio, "neutrality" is about just frequency response and basic distortion. So, what is "neutral" when it comes to a complex, 3 dimensional sound field composed of direct and reflected sound? Yes, there is some basic guidance there provided for speakers in playback by the Harman testing. But, measures of frequency response or distortion alone do not define or tell the whole story of imaging.
I still believe you are inaccurately minimizing the role of reflected energy, not only in the room in playback, but also in the recording venue itself. Mikes do not hear like people do, so even different mikes with nice flat, on axis frequency response may pick up something different in the venue live depending on their spatial response patterns. They deliver a different image as a result. So, which mike pattern is more "neutral", even if on axis frequency response is flat?
Direct sound superficially dominates our sense of hearing. In fact, many believe quite incorrectly that only direct sound is important. The rest of the sound field, reflected energy, is unimportant, they think, again superficially and incorrectly. But, the Haas Effect makes clear that sonic perception of wavefronts has much to do with timing. Earlier sounds dominate our perception and mask the presence of later, reflected sounds. The presence of those later masked sounds, mainly reflections, becomes perceptable only if they are removed or altered from the original. And, many experiments have shown that the room acoustic, including reflections inseparable by the ear's timing response from the direct sound, alter the perceived sound in significant ways, tonally and spatially. Even cave men knew that spoken sounds in the cave were quite different from those outdoors from the same speaker. They probably just did not understand why, the same as many audiophiles today.
Obviously, the ear is able to separate longer timing intervals between direct and reflected sound as distinct and identifiable echo or reverb. But, much reflected sound is inseparable from direct sound, beneath the ear's timing threshold, and comingles with direct sound in a non-obvious way, altering the perceived sound.
Empirically by many studies in the concert hall, listeners in all but the first few rows are hearing a lot more diffuse, reflected energy than direct sound. Where is the "neutrality" in all that, especially if listening in stereo which throws away the directional information, except for frontal L-R and phantom images in between, including the depth phantom. But, the sound energy in the hall is actually omnidirectional, not just all coming from up front. And, our ears are omnidirectional. Again, "neutrality" does not answer this.
So, where am I headed with all this? For one thing, it is why I think Mch is a closer approach to live sound in the hall because it preserves much of the omnidirectional properties of reflected sound via a surrounding speaker array and phantom imaging in between. That is as opposed to stereo, where everything is directed or artificially redirected at you from the front.
Systems may be measurably and subjectively "neutral" in frequency response or other measures, yet still differ dramatically in imaging.
But, even in stereo, listening room reflections may appreciably narrow or widen the apparent image by altering the mix of direct sound to room reflected sound, as well as the direction from which the reflected energy predominantly emanates. That is true even with a certifiably "neutral" system. I would have thought that by now everyone has experienced this by experimenting with speaker toe in or other placement issues. And, note that I am not talking here about room modal issues in the bass.