If you look at the original Bionor drawings (you can find them at klangfilm.free.fr) you see that the "bass" horn is actually made out of two sections, the outer is curved, the inner is conical and expand both horizontally and laterally (more in the lateral), as opposed to the outer section. This gives the perceived "negative expansion", which is quite probably just a photographic illusion. Why Klangfilm chose this approach is beyond me... |
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