CHN40 compact mass loaded horn box

Thanks to Dave for the new drawing and Scott for the design.

I only posted about the drawing because when you (I) build things your mind's eye expects the cut pieces to look like the drawing. When they do not look like the drawing doubt arises and you work through the process of did I mess up first, then to other possibilities. A few times this has stopped me until I could work out why what I had made deviated from the drawing. Trying to avoid that spiral of doubt.
 
Does the driver entry location line up with (eliminate) the 3•Fb notch or is it aimed a little higher up strategically ?
Good Q; 'kinda sorta' wish the axial length of folded designs is always shown (at least on PPV/'bespoke' designs) based on Brian's/this (71.4 cm):
0Horn folding_84a17487_vvv-1.gif
 
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Good Q; 'kinda sorta' wish the axial length of folded designs is always shown (at least on PPV/'bespoke' designs) based on Brian's/this (71.4 cm):
View attachment 1134310
Some of these ideas seem like akward ’guesses’ based on ‘flow’ as a distance changer instead of a sinewave shape defining high or low concentrations of vibrating air particles Stuck in a pipe and it’s exit relationship to the last P/v node

This ’stuffing’, or lining, assumed to be the fix all to whatever is ‘off’ as a bandaid to the impossible ‘guesses’ we are stuck with maybe?
 
Absolutely; this is why I model the individual sections of a pipe (including bends etc.) as far as possible rather than taking it as a single element. Never 'perfect', but usually good enough for these purposes. TBH, except in extremes, for straightforward pipe designs I've found a lumped model tends to be fairly representative for Fb and the lower harmonics, with variations being on the detail level rather than anything more profound (by which point relatively minor differences in the line damping or driver production tolerance tend to have as much impact). I still try to do a more detailed assessment of the geometry when possible though, for the reasons you mention -as changes to expansion, aspect ratio etc. become progressively more dramatic, so the deviations from 'basic' conditions (ha! the underlying maths still makes my mathematically-challenged head ache 😉 ) become more obvious, especially as frequency rises.
 
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