NEW PROJECT - DIPOL MEMBRANE

[♚Chello]

NEW PROJECT - DIPOL MEMBRANE

Many years ago launched speaker manufacturer DALI a magneplanar speaker with bass cabinet and conical bass unit.
In order to get the bass unit to have the same dispersion pattern as the magneplanar unit, they made a frame around this over which they stretched a plastic foil.

Inspired by this, I made my first version in 2003, where I made a frame that I mounted around the bass, midrange and treble units, over which I stretched a plastic foil.

Once assembled, this had an unreal effect:
No matter where I listened, I heard all units from the same point.

A little later I had a visit from my brother and his children, and one of the children poked a hole in the foil before someone could stop her.

Many hours of work destroyed in an instant... 

Years later I made another version, this time with Klipsch Reference RF62 MK2 cabinets.
Here, too, the effect was formidable - the sound came from one point regardless of the listening position.


   


I now intend to take this idea one level further, because I will make round frames on the Philips horns, and stretch a plastic film over this.

[♚Chello]

DANGEROUS WORK
I am now milling rings for my Philips horns.
These are made from 20mm 7-ply plywood.
Finally, plastic film is stretched over it, and it is mounted on the outside of the horn, so it becomes a "magnepan" horn.

This is very dangerous work, even if I screw the milling machine's attachment firmly into the plate I am milling, and also fasten the plate with 2 screws close to the center.

A milling machine is the most dangerous of all machines, and work on milling circles is particularly dangerous.

The ring has to be milled a few millimeters at a time, and there is a LOT of dust.

Safety glasses, hearing protection and a dust mask are absolutely necessary.


   


   

[♚Chello]

I had to make new rings, because the first ones did not fit 100%.
The milling machine had changed position slightly during milling, and thus the rings were a bit too small.

The new ones are only 10mm thick, and in MDF.
I have drilled holes for mounting in the horns and painted them black.

What now remains is to attach double-sided tape to attach the plastic film to.

 


   

[♚Chello]

FINISHED

This was very, very difficult to achieve.
Although I have many years of experience in wallpapering, furniture wallpapering and work with foiling, this was almost impossible to achieve.

The plastic film is only 2 tenths of a millimeter thick, and non-elastic, plus it is super static - all dust sticks immediately.

I made this "invention" 21 years ago and it was much simpler then.
Could it happen that they have changed the composition of the plastic, and produced it from recycled plastic..?
I have no sense of recycling, because the quality is always reduced.

I have invented a method to stretch the plastic wrap:
A white plate of 60 x 40 cm is used:
First I make a circle equal to the diameter of the ring, and then I tape double-sided tape squarely around it.
The film is then stretched from one end to the other, and finally the tape is lifted on each of the other two sides to tighten the film.
VERY difficult.

   

At the very end, the ring with attached double-sided tape is placed on top of the drawn circle and pressed hard against the plate.
Then it is cut around the ring to cut the ring loose from the foil attached to the plate.
Finally I colored the finished membrane with a large marker (!).

But how does it sound ?
Incomparable!
Imagine that you have a tweeter that has a dome of 25mm, and that you increase this to 300mm.
The problem with small domes is a very limited dispersion pattern.
When you listen to these horns with the attached extra diaphragms, on the other hand, the dispersion is colossal - they spread the sound everywhere.

This must be said to be a very successful project, and I am looking forward to the next step, which is to make a frame for an extra membrane on the Klipsch cabinets, and finally on the horn speakers.


   


   
Big creases - I had to do this 4 times before I was able to avoid creases.

   


   

[⚝Roshure]

Hello Mr. Chello. 
Really an art of handcrafted speakers!!


Fernando

[♚Chello]

Hello Mr. Chello. 
Really an art of handcrafted speakers!!


Fernando

Fernando
Thank you for your delightful comment.


I have always had a sense of design within Art Deco, and also always try to create my own design.
I'll make better pictures later.

[♚Chello]

WOW !!! 

I was shocked when I heard a style I just edited:
Everything normally sounded clearer in the Stax headset, but with the new membrane horns everything became super detailed; actually TOO detailed.

I have to turn the volume down a bit.