Low frequencies carry most of the energy and power in music, so a Basshorn needs to be constructed as rigidly as possible, with the minimum of resonances that colour the music.
This Basshorn is large, so very thick panels would be heavy and even more impractical.
In principle I prefer to brace & stiffen thin panels, rather than use thicker & heavier sheet material.
Plywood is lighter with better strength-to-weight ratio than MDF or ‘chip-board’ – in my experience, it sounds better too.
The design in principle: (see also Midhorn + Basshorn (Part 2).)
This Basshorn is made in 2 parts – (1) bottom Basshorn Mouth, (2) upper Folded Horn-Driver Chamber-Throat.
1) Basshorn Mouth:
True corner loading – floor + 2 walls.
Side panel double-wall, box-construction with internal ‘skeleton’ frame – 12mm plywood.
The bottom bend is curved 90 degrees in 3 directions – using Bendy Ply (see below).
The ‘Bendy Ply’ (flexible, bendable plywood) is 9mm thickness (used in single & double layers).
2) Upper Folded Horn:
First layer, 9mm Bendy Ply.
Second layer, 2 x 9mm Bendy Ply
Driver Rear Chamber (throat chamber) + first horn section.
Front panel added – with driver mounting hole. Note that the internal horn cross-section is kept as ‘square’ as possible throughout.
Rear panel access-hole for Driver Rear Chamber.
Driver Rear Chamber (throat chamber) – with front and rear access holes.
Side panels added – 18mm plywood.
Double layer top curve (2 x 9mm) Bendy Ply) + sloping front panel.
The sloping front panel is stiffened internally and….
…also to form an internal curved horn flare.
External Stiffening Ribs were added to the large rear panels – top and bottom.
Test assembly of the top & bottom parts.