Midhorn + Basshorn (Part II)

This is my room plan – 6.1m x 3.6m (20′ x 12′) – showing the ‘compound’ Mid-Basshorn cabinets:

The driver was originally a Lowther PM4.  (Very costly and high maintenance.  Now, I am using the inexpensive Seas FA22RCZ.)

As described previously, a Tractrix front horn produces midrange frequencies above 140-180Hz.  An Exponential rear horn provides the low frequencies.

Horn-Room-Plan

The final design of the Basshorn, with front Midhorn is below.

This Basshorn is designed for corner-loading:

  • To reduce horn mouth size – by 1/8.
  • For the most uniform low frequency in-room response.
  • To minimise loss of room floor area – by internal folding sideways and corner-positioning.
  • The horn mouth faces 2 directions – along both the front and side walls – and the floor.

Horn-Section-B-B

Key parameters:

  • Horn length 4.05 – 4.10 metres
  • Throat size 80 sq cm
  • Mouth size 10,370 sq cm
  • Flare rate M=1 (exponential)
  • Driver throat chamber 14,500 sq cm excluding driver (can be reduced to 8,500 sq cm by inserting solid infill material)
  • Design Fc 29-32Hz

Horn-Plan

Construction will use 18mm plywood – for high stiffness/weight ratio.  Also for better sound (compared to MDF or Particle Board).

The mouth area will use 2 layers x 12mm plywood – for greater thickness and strength in this area.

Section-A-A

Stiffening ‘battens’ are screw-fixed on the exterior back and sides, where required to dampen resonance.

All bends are smooth-curved, using ‘Bendy Plywood’ – 2 layers x 9mm thickness.

Horn-Sect-BB

Next:  Basshorn (part 3 Construction)

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One thought on “Midhorn + Basshorn (Part II)

  1. Pingback: Basshorn (part 3 Construction) | D a r k L a n t e r n

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