The Loudspeaker Frame (MDF or plywood)

The ribbon loudspeaker dimensions

Figure 1

The wood I used was a MDF fibreboard, 30 mm. thick, a great width which gives a very good resistence to vibration and a very sturdy heavy frame for the membranes (together with the perforated metal plate), helping considerably to make the bass frequencies all the more attractive, something that can be considered the soft point of the project.

That’s is, at least, the theory, I now think it’s overkill and a thinner wood frame is the way to go.

Having such a thick piece of wood, makes the cutting a real adventure, MDF boards create an incredible amount of wood dust, so beware!

It also creates a problem not considered in the original project (they were smarter), how do you get the magnets close enough to the membrane?

It is much heavier than the original project frame, the loudspeaker foot has to be much stronger than they recommended, obviously!

I think it is best to have the wood cut by an expert, here in Chile that is very inexpensive, that may not be the case in your country.

If you plan to paint your loudspeakers do it after it’s been cut and before you start doing anything else.

How to cut the MDF plate for the speakers

Figure 2

Here are the original Danish project dimensions:

a=30 cm
b=22 cm
c=95 cm
d=4,5 cm
e=95 cm
f=14,5 cm
g=11,5 cm
h=75 cm
i=130 cm

If you want a bigger loudspeaker, use the following proportion relationship:

4 : 3 : 13

This also changes other dimensions, so be careful and check everything out before doing anything irreversible to your material.

The list of materials

The construction recipe

Contact: Magnetostatic Loudspeakers