- Apr 22, 2016
- Princeton, Texas
And I thank you simply for your patience and determination in digesting what I had to say in it's entirety. I honestly don't like writing a lot, I just have trouble in being confident I am coming across as clear to the other person, so apologies for making you go through those walls of text twice.
You're not making this easy. You give me zero excuses to get riled up; quite the contrary in fact. I try blowing you off anyway, and...
Though your posts to others shows that we hold sufficient common ground on the matter. Like when your discussion about reflection properties and their timings. So it seems you and I already see eye to eye on soundstage from a recording procedure.
... you respond with pointing out where we share common ground. So now it's like I'm trying to break up with my conjoined twin.
How about this: Let's forget about me wanting to "demonstrate something", and let's just have the conversation that seems to be happening anyway.
Just so you know, I know very little about the actual recording process; my comments have been mostly if not entirely about loudspeaker/room interaction. I'm just a speaker geek turned small-time manufacturer.
A couple of times you've mentioned "making drivers have more soundstage" (or something like that) being a position taken by some. I'm much more of a radiation-pattern-obsessed guy, but imo it is possible for some drivers to have less precisely-defined sound images. This involves the short time interval preceding the onset of the Haas effect, so let me explain:
The Haas effect (suppression of localization cues from reflections) does not begin at the instant a new sound arrives; it begins after about .68 milliseconds. That initial .68 millisecond "window" is enough time for a sound which arrives from one side of your head to wrap around and reach the other ear, with the arrival time difference at the two ears informing the ear/brain system of the azimuth (horizontal direction) of the sound source. As you well know, after that first .68 milliseconds the Haas effect kicks in and the ear ignores directional cues from reflections for the next 20 milliseconds or so, but during that interval it is still picking up loudness (and therefore timbre) cues.
If a driver or loudspeaker baffle has diffraction or a reflection, that is a re-radiation of the initial sound delayed by an inherently short path-length difference, thus typically arriving at the ears well within that initial .68 millisecond time window. This results in a FALSE azimuth cue (recall that the inter-aural arrival time difference is how the ear/brain system computes azimuth). Well actually it results in four false azimuth cues... two from each speaker, each arriving at the two ears. The result is a blurring of the sound image width. So for good sound image definition, we want drivers (and baffles) which do not have reflections or diffractions arriving within that first .68 milliseconds. Next-best would be for any (hopefully fairly weak) reflections or diffractions to arrive as early as possible within that first .68 milliseconds, as this will result in a smaller-angle "smearing" from the resulting false azimuth cues. One implication of this is, narrow-baffle speakers generally should have better sound image definition than wide-baffle speakers (all else being equal).
So I'm not really into "this driver images better than the rest", but I am into "that driver has inherent imaging problems". Diffraction horns, sharp-edged waveguides, and non-flush-mounting of tweeters are examples of things which can cause a driver to have imaging problems arising from false azimuth cues. (This is not the only issue which can arise from these very early reflections and diffractions, but I don't think it's one that is very well known. Strong early reflections or diffractions can also make the location of the loudspeakers obvious to the ears, which is a distraction from the spatial information on the recording.)
The foregoing probably seems like a trivial tangent in the big scheme of things, but imo one has to get a lot of little things right at the loudspeaker (and room-interaction) level in order for the spatial cues on the recording to become perceptually dominant.