See the post above. My view is the timing issues are more important to audibility than the frequency response ripples. They are also harder to measure. The listening reports and my own experience involving edge diffraction effects relate more to imaging which appear to support this conclusion. It's a larger issue with dome tweeters and wide dispersion, not a large issue with fullrange drivers, unless, like you say, they effectively have a dome in the middle. This is why I asked about measurements that could show it and suggested that simulations are probably more helpful. I don't see how FR ripple can effect imaging as much, but I'm open to suggestions and correction.
In which case we are both simply stating that flush mounting drive units that are designed to be flush mounted should yield superior results than surface mounting. It affects frequency response -no surprises there, well known & illustrated, and I provided an example from John of what it can do in that regard. Imaging? Quite possibly, extent depending details / implementation. That's a different, albeit connected field you raised, which also implies it is better to flush mount drivers designed for flush mounting whenever possible.
Re simulation -sure, although you'd probably need to go finite element in some detail to do it effectively. Ray tracing has its limitations when you get into the fine detail, and it's likely in that that you'd need to go to. Personally I'm on the fence to some extent on the subject; on the one hand, I'm subjectively an imaging hound; it's something I tend to put a lot of value / emphasis on. On the other hand, apart from c. 'live' recordings, the engineer in my views it as an engineer's phantom, since in the bulk of studio recordings it's created at the mixing desk and entirely artificial. YMMV on that front.
Something I do find amusing in the abstract is the proliferation of contradictory views / experiences. Earl for e.g. favours and promotes highly controlled directivity as innately superior WRT imaging abilities, however you might wish to view that term. Meanwhile, many others favour omnidirectional speakers, dipoles, array variations (which are certainly directivity controlled but not necessarily in quite the same way as, say, a Summa) for almost exactly the same reasons, at least in terms of feeling they offer a more realistic image / soundstage / representation of the soundfield on the disc / file / tape / wax cylinder. Same for those who favour narrow or wide baffle speakers: you often find fans of one or the other approach state they favour it for what they consider its 'superior imaging' (or something roughly along those lines). In that broad regard, I suspect we'll find this is always going to come back to a matter of personal preference and perception.
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No, I was simply stating that there is a debate around the subject
I don't think all the views are that contradictory when you consider the differences perceptually between early and late reflections. Of course some like to create "differences" in order to have a USP.
It's worth baring in mind Earl's credentials and the amount of well performed testing he's done.
It's worth baring in mind Earl's credentials and the amount of well performed testing he's done.
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I would say that he endorses low diffraction/early reflections for imaging. A good omni speaker with careful placement could do all that.
No doubt they do. The entire point I was making is that different people favour different approaches because they do perceive things differently. As individuals, that isn't contradictory. In engineering terms it can be regarded as such since different people favour different approaches to a given matter. Which is certainly where some of the interest lies, but also means you'll never get universal consistency / approval.
Re Earl's credentials, we all know and respect them, along with his research and data. However, that doesn't mean that his opinions or preferences are universally applicable, or that everybody follows the details of his takes / design approaches. This entire forum is evidence to the wide variety that exists.
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Possibly. But not all do that, or even aim to, and those have their fans. I can't say I'm one of them, but if that's what some like or feel gives them whatever it is they happen to be looking for, power to them.
What point? Sorry, I'm not trying to be obtuse, I just don't understand what you are saying. Are you saying Earl's research and data are good? If so, yes. They are. Very. And he bases his opinions on it, which is a fairly logical thing for a researcher and designer to do. 
However, that does not necessarily mean that everybody else takes identical design approaches, or even necessarily has identical opinions when using the same or similar data. Which is not a criticism, nor a critique, nor intended to be either. It's just a statement of fact, which anybody can observe by looking at the proliferation of different designs and approaches that are taken by many different people, some of whom may not even be aware of Earl's work, although no doubt they'd benefit if they were. That's it. Nothing else to see, nothing else implied, hinted, suggested, intimated, insinuated, alluded or anything else for that matter. Period. I'm not sure if I can make myself any clearer on that point.
However, that does not necessarily mean that everybody else takes identical design approaches, or even necessarily has identical opinions when using the same or similar data. Which is not a criticism, nor a critique, nor intended to be either. It's just a statement of fact, which anybody can observe by looking at the proliferation of different designs and approaches that are taken by many different people, some of whom may not even be aware of Earl's work, although no doubt they'd benefit if they were. That's it. Nothing else to see, nothing else implied, hinted, suggested, intimated, insinuated, alluded or anything else for that matter. Period. I'm not sure if I can make myself any clearer on that point.
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That is a problem shown here that many have on this forum, their opinion should be the universal truth, while even the specialists like Earl Geddes and Floyd Toole don't agree with each other and often change opinion on all those subjects. There are many ways to get to a good sound, and we even don't agree what a good sound is, as hearing is subjective. Not everybody hears the same or wants the same kind of sound. So point something as the universal truth is ********.
That doesn't mean a scientific approach is useless or those books and theories are worthless. They are very usefull for all, and all should read them. But they are not the holy bible of speaker building, they are opinions of people with a lot of knowledge and experience. And you, as speaker builder should see what fits in your goal, which may not be the same as mine or his...
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