Back Loaded Horn search

[Guy Boisvert]

By remote chance, just wondering if anyone came across a plan for these back loaded horns ?  Provenance is from Europe, Norway to be more specific. I saw a note somewhere that they were named speaker of the year....I don't know which year.

[JamieMcC]

When I saw your pic and you mentioned Norway I thought of Troels gravenensen as his name sounds very Scandinavian but it turns out he is from Denmark not Norway his website is a fantastic read a real mine of info on diy speakers. I was doing some reading on full range speakers a little while ago and booked marked the site it as there was so much info.

http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm#INDEX

[Guy Boisvert]

That is a fantastic source of information ! Thank you so much for the reference. This winter, I built these Cornu Horns for my son. I was surprised by the quality of the sound. The speakers are Fostex.

[JamieMcC]

Nice job and what a fortunate son you have. What amp is he running them with? Have you any good links about them, the spiral inside looks might complicated.

[Guy Boisvert]

I followed the method outlined here:

http://sebastian-pitkanen.blogspot.ca/2006/07/cornu-spiral-copy-horn.html

I found it difficult to make the spirals using the material  described; so, I made the initial inside curves using thin sheets of styrofoam, - then used 1/8" plywood for the longer curves. The foam was scored with a sharp knife every 1/4 inch or so to render it flexible. A glue gun is a must.

  Instead of leaving the sides open, I used half inch thick  solid pine and made four openings. The flat black paint makes four side openings disappear to the eye. The pine side sheets also make the unit very solid, not flimsy at all.

I did the front with burl wood veneer.....basically four identical triangles cut to size with the speaker as the focal point. Finished the veneer with hand rubbed Minwax poly.