So its deeper than just FR? That brings more questions, I thought FR/Phase are tied together. I think I am thinking of the same thing as you, except I am leaving out that everything below the upper HF corner is also is constant at the point HF drops, so I guess I am just thinking about my own situation, not every situation.
I am still speaking on my personal situation but I think other configurations have similar performance. I imagine the off axis transition as the onset of a set of filters, most commonly, is the onset of a high pass filter. As we move off axis, when the level on the highest frequency criticized, drops, -3db or perhaps -6db. With my HF, everything is pretty constant as we move off axis, with the exception of what is effectively the onset of a Low pass filter, the filter point lowers as one moves further off axis. When that low pass filter causes 17khz to drop significantly, for example, I call that the limit of the sweet spot. If everything below 17khz is still constant, am I wrong?
Do we have any visual examples of this? I believe that the frequencies that are smaller than the diameter increase in directivity with the source in the end of a tube, but I don't know why.
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Call 17kHz a limit of a sweetspot?
Above 8kHz local absorption of a generic room goes up significantly.
So even if we don't take our own hearing into consideration, the importance of a super strict constant directivity for 10kHz and above is debatable.
Obviously you shouldn't just let it fly, but there is definitely a lot more room for error.
I had the idea to do something like this with a large elliptical horn and matching woofers on each side the horn mouth, Then I remembered that someone was basically already doing that, minus the twin subs for each channel. Select people on the board seem to keep hinting that vertical reflections are more an issue than horizontal. The next obvious evolution for me to get the waveguide bigger is an elliptical with its vertical axis the tallest and with the horizontal dimension being the width biggest acceptable. 30-36" seems to be a good place for me. To get the center of the horn at ear height, 48", things get pretty big at 96" tall. From there one could use the large surface of the flare for many purposes. I would create an MTM, seems logical. Maintaining the 200hz XO point, I would slot load 18"s at the top and bottom.
How long you think that would take to print
How long you think that would take to print
Why would you want it to be tall and narrow? I guessed that it was to increase directivity on the vertical, but maybe not.
This is a very tricky one.
In just an open space (outside), our vertical hearing and positioning is just pure crap.
That has mostly to do with the fact that our ears are one the same plane.
The shape of our ears seem to help a little bit.
There has been experiments done that show that when taping these of to make them smooth (leaving just the ear canal open), this is even more difficult.
(I think there are a couple of good Youtube videos that show this)
In a space however, there are delayed reflections.
I haven't been able to find ANY proper literature going into details about the audibility that focuses specifically to vertical reflections.
In almost all cases it's all being put on the same pile; "just reflections".
Knowing that our hearing isn't great in positioning things vertically, I have my doubts it's gonna be great in a closed space as well.
The hearing has to rely entirely on the processing of hearing delayed sounds.
But again, there is no proper research to back up either point of view.
All narratives are being told from just a general acoustics point of view, not from a human hearing point of view.
Are you sure that you thought that through? The directivity is narrowed in the horizontal that way.
The Archimedes project with Soren Bech, KEF and B&O was interesting. Papers attached here.
https://www.audiosciencereview.com/...nd-measurements-audioholics.23519/post-791482
You seem to be talking about imaging.
I find vertical reflections to be an irritant, a mental distraction, especially when the spectrum is off, as it might be when afflicted by lobing.
Worthwhile managing in a design.
Also you can perceive the direction the reflection is coming from, which can make it distinct. Perhaps the reflection delay plays a part in that, too.