A dream of mine

[JMFahey]

I started answering in your other post.http://www.diyaudio.com/forums/construction-tips/225974-speaker-unit-scratch-anyone.html#post3290313
Yes, I make speakers from scratch, but don't want to double post.
And was also going to mention the Argentine Engineer JJ Bertagni.
He sold a lot all over the world but left the Country in 1976 when the Military fired the President and started destroying our Industry, turning Argentina into a Wall Street "investment bubble" and unemployment nightmare.
Similar to what's happening in USA today
Some pictures of the Bertagni "plano sonoro":

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[CLS]

That reminds me of the yamaha.

Look for NXT or DML, you may find something similar and interesting.

 

[Einric]

A problem I could see is the voice coil in the center would just push the middle of the cone out.
With that fragile of a cone I would think there will be problems.

Blaupunkt had a series of flat subwoofers that used a frame driven from the voice coil out to the perimeter of the cone at the surround.
This way the voice coil would push the inside and outside of the cone like a piston.

 

[JMFahey]

Don't worry, that cone is quite rigid.
Styrofoam comes in all renges of strength and density.
The one chosen for speaker is quite strong, and is no flat at all, it's thicker or thinner where it needs to.
That can be easily seen in the pictures.

 

[venomizer]

once I was noticing someone trying to make a membrane out of a half-cut christmas tree ball, as basis he used an old papercone driver, he ripped out the original membrane ...

hi dynablaster! the world is small...

 

[Godzilla]

I bought a few of the Dayton NXT type products and played around with them. The best results I was able to obtain was placing them onto the large window behind my desk. The room filled with sound but in a different way than traditional speakers. It wasn't the best sound ever by a longshot but it certainly filled the room with sound. Putting them under your desk or onto different things makes muddy sound but the window was very cool.

Zilla

 

[Frank40]

Here is a short update.... Well the systems works but I did not end up with a full range, I would guess it when up to 7-8KHz. I did some research and found that I need a new magnet system and voice coil to expand the frequency response.

Now I am working on a 6,5" full range with a vacuum form Depron membrane. But I have a hard time getting the material for the magnet system, so it will take a while before I any news.

 

[venomizer]

Frank40: your speakers are very nice looking!! I like these DIY-membrane work a lot...

Link to High5's very special DIY 28-inch Subwoofer (german forum Syraha)

 

[Frank40]

Hi there

It has been a while sense I update this thread, well it has taken a unexpected turn... The result I am getting now is way better than I ever expected, so the project is way bigger now. I found a thread on field coils started by a guy called Hentia, he relay know some good stuff, and I am now working with him to make some nice units.

See his thread at: http://www.diyaudio.com/forums/multi-way/212953-project-ryu-diy-field-coil-loudspeaker.html

If you look at some of the last pages you will find some great stuff. This will be my last post on this thread, as I am posting my result in his thread.

Take care
Frank