Evaluating the vertical dispersion characteristics of a loudspeaker is extremely difficult and far too little researched.
In my experience, I would even go a step further and claim that the heard vertical behavior of a loudspeaker is sometimes even counter-intuitive to its vertical measurements.
There are loudspeakers that are very constricted in vertical dispersion, in a certain frequency range, for example some Pseudo-D'Appolito speakers, but the timbre is very insensitive to vertical changes of the head.
Here is an example of a loudspeaker which, for my listening perception, has almost no tonal change when changing the listening position from sitting to standing.
Although the vertical dispersion pattern upwards is far from perfect. It even shows a comb filter effect at large angles.
Normalised vertikal FR 0 to +90deg:
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In the simulation with an LR4 crossover, the spectrogram looked like shown below. This would surely get negative ratings from
@amirm in a review. In the real loudspeaker I hear at the moment even primarily with an LR2 crossover, which would "worsen" the spectrogram even further, purely measurement-wise - although the heard vertical behaviour of the speaker is damn good.
View attachment 83204