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In the Forum: Horn-Loaded Speakers
In the Thread: Evaluation of tractrix curves based on visual surface reflections.
Post Subject: You are too worried about nothing.Posted by JLH on: 6/20/2006
 jessie.dazzle wrote:
It is interesting to note that the evaluation tool shows lines radiating perpendicular to the curve at any given point, just as the sound wave is supposed to be oriented as it progresses along the horns length. 


JD,

Your attempt to perfect your horn is admirable, but in the end will not make an audible difference. You above assumption that the wave remains perpendicular is incorrect. In the perfect horn, assuming you have absolution phase and time alignment at the throat, the pressure wave front starts off as a flat plane wave. However, as the wave travels down the throat it becomes more spherical in shape; this is what the tractrix profile predicts.

The reflection points that occur in your model are of no importance. The more important shorter wavelengths will not be affected. The horn diameter, and the frequency it corresponds to, at which the reflections occur is beyond the high frequency beaming point of the horn. The frequencies that are near that point of reflection are already so long, they are acoustically invisible if the horn is properly loaded. See, once the lower frequencies are well loaded to the room, they begin to be more omni-directional and do not suffer from “line-of-sight” reflections. However, you must have a long enough horn to load your room; which in this case should be fine at 1M in length. Once energy is coupled to the room, it can break the chains of reflection.

You can build your horn anyway you want. If it makes you feel better to build the modified horn, then build the modified horn. There is such a small difference you will not be able to hear it. I would not waste time building both, just choose which one you want to build and take it easy and forget about it.

Rgs, JLH

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