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In the Forum: Horn-Loaded Speakers
In the Thread: It's might be another project...
Post Subject: This might be boring, but…Posted by a.anagnost on: 10/19/2024
Romy, light a cigar, make yourself comfortable and try to follow my thoughts.
Both contraptions are topologically equal: If you consider that in Jensen, A is a triangular box equivalent to the triangular box (rear chamber) of your contraption. (Jensen is just talking to the 2 ducts/horns through the 2 (point B) slits).
Imagine unfolding everything and putting all components in a straight line: We derive to the same basic schematic (which is a dipole):
A driver, attached to a box (defined by some volume Vb) attached to a (conical) horn shaped duct (defined by some throat surface St, some mouth surface Sm and some flare length Lf).
Obviously:
If St=Sm, the schematic becomes a typical Bass Reflex (BR) schematic.
If St<Sm then we have a BR with horn duct. And now we have a problem: We have to tune that horn in very special way as we don’t want to introduce peaks due to horn gain and due to BR miss-alignment (keep in mind that this horn acts also as port/Helmholtz resonator in order to tune the BR response).
Based on the above, the BR theory may/can explain the observed differences using random (Altec and Vitavox) drivers:
We need specific Vb for each driver and specific tunning of the horn duct.
In your case (since all dimensions are fixed), If I wanted to use the Vitavox, I would reduce Vb.
Dipole
One important factor is the distance between the driver and the (very large compared to traditional BR boxes) side openings. This can cause severe cancellations especially in the 150-300 Hz range. I suppose that placing the driver near the bottom (or near the top) of the baffle would be beneficial.
Corner placing
This is uncharted territory for me too. My biggest concern is that practically, we are using a fraction of the side walls as an excuse. If those boxes were ceiling high…but still we are talking about a very fast opening horn…
In fact, I feel more comfortable thinking that I have a BR build for corner location: Efficiency is increased, reflections from those 2 walls are eliminated and that’s it.
Antonis
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