Materials for the Duelund Inboard Concrete Monster

Here is an overview of the MDF cutouts required to build a pair of the small concrete reinforced horns, also known as "The Concrete Horn". The list is correct for the use of 19 mm chip-board, MDF recommended, where 20 mm thickness should have been used as per a simple upscaling of the contruction. Please be aware that this is the list of items required for building a pair of big horns for a 10" or a 12" unit.

Please also be aware that all measurements are in millimetres, and that precision is required, preferably to +/- 0.1 mm or better. You could use marine grade birch plywood instead, it will be heavier, it will be costlier and it will be more rigid at the price of possibly being slightly more resonant in the midrange so the general sound of the construction might be a bit harder. A good compromise could be to use birch plywood for items A, B, C, D and E, and to use MDF for the rest.

19 mm board:

A) 2 items: 416 mm X 1072 mm

B) 4 items: 414 mm X 1110 mm

C) 4 items: 414 mm X 416 mm

D) 2 items: 416 mm X 695 mm

16 mm board:

E) 2 items: 376 mm X 1072 mm

F) 4 items: 113 mm X 548 mm; cut-out as shown on plan 2!

G) 4 items: 200 mm X 570 mm

H) 4 items: 200 mm X 455 mm

I) 4 items: 200 mm X 310 mm; cut-out as shown on plan 2!

J) 4 items: 186 mm X 103 mm

K) 4 items: 165 mm X 103 mm

L) 4 items: 53 mm X 103 mm

M) 4 items: 44 mm X 103 mm

N) 4 items: 113 mm X 103 mm

Items J and N can be substituted with one piece measuring 299 mm by 103 mm, however if so, then it is required to make a polyfilla filling where N would have been at the angling of the separate items, it might be an option to partially saw through the replacement item from the "rear" so as to be able to bend it to the required shape. It would then be required to close the opening on the "rear side" with polyfilla or similar so that the surface is completely smooth.

Additional materials include screws, glue, cement as per recipe and a basic minimun of general hobbyists tools and semirounded pieces of wood as obvious from the illustrations. This is not a construction for the faint of heart, nor for the beginners, so you might want to have some woodworking and DIY routine handy too, at least in an amount that allows you to grasp some unmentioned safety precautions that you are supposed to be well aware of. This is not a "kit", it is a construction with some guidelines and an unpleasant lack of "undo options" because of the need for extreme structural rigidity.