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.


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.


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


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.


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.


Next:  Basshorn (part 3 Construction)

2 thoughts on “Midhorn + Basshorn (Part II)

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

  2. Pingback: Compound mid + basshorn (Pt I) | D a r k L a n t e r n

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s