Omni Ribbon

[båndsei]

I am in the proces of making a omni ribbon like the one from Raal.

Here the steelwork.There is 16 magnets 70x10x6mm.
More later.

Bernt"Båndsei"

 

[båndsei]

Magnets are placed as in a planar and the ribbons have to be app. 2mm in front of the magnets.Picture shows a test.

Bernt

 

[a.wayne]

How are you going to control phase issues with the rear wave .....

 

[båndsei]

I am inspired by this one.
The inside of the"tube" has to be dampened .

Bernt

 

[båndsei]

My second attempt to make a omni ribbon. It plays,but it has low sensivity.It has 6 ribbons playing in fase ,a sort of bipole i think. I have to listen to it in a setup like this one:

Bernt

 

[khbaur330162]

Very cool. Idk how thin that micropore tape is that you're using, but this might be a good candidate to etch your diaphragm on Aluminized Mylar due to its size and the sensitivity issue.

Watching with interest.

 

[george a]

HI Bernt

Which way are the magenetic poles of your magnets facing?

Outwards as per a planar bass unit or face to face as in a normal ribbon tweeter.
If the former , this may account for your low sensitivity.

Also are you using a transformer ? - how are these units being driven?

 

[stujonesmd]

I find diy ribbon speakers fascinating. I have had some experience with commercial low cost ribbon drivers, most notably the HiVi $40 or so ribbon tweeters, the lower cost Beston ribbon tweeters, and the larger (and, prior to Chinese Neodymium Ripoff, very inexpensive) Dayton ribbon midrange-tweeters. The Daytons, in particular, sound very good to me, and are still inexpensive enough to justify purchase of 4-6 units for an array. I am currently using 2 of these mounted on top (!) of smaller MTM home brew (dual 5" woofer, single Titanium dome tweeter) small (12 x 10 x 7 inch) boxes, mounted under a desk (which is why the top mounted ribbons). For home brew speakers these sound pretty good.

Has anyone here tried to use radial wire embedded in the speaker membrane for a home brew ribbon?

 

[båndsei]

In the first model with 16 ribbons magnets are outwards in the second one with 6 ribbons they are face to face.Resistance is 3.5 ohm,so no use for transformer.

I am only using small tape behind the membrane and 16mm on top and bottom.
Later i may use mylar .

Bernt

 

[Andrén]

I could recommend you to put damping material in the middle, and try to make it more stuffed in the middle and less stuffed towards the ribbons.

Also try to have som tension in the ribbon itself, that will give you some more output, and make sure the ribbons is well centered in the magnet gap.

Good luck!

 

[karellen]

Impressive!
Please go on

 

[båndsei]

My next move is to make the unit 80mm. longer,8 more magnets,and find a better way to mount the ribbons at the ends.

The "tape"/ribbon is app 85cm. and will be app 120cm. in the next version.
[URL=http://img715.imageshack.us/i/007jus.jpg/][IMGDEAD]http://img715.imageshack.us/img715/8535/007jus.jpg[/IMGDEAD][/URL][/IMG

Bernt

 

[båndsei]

This one has longer ribbons and a bit wider (21mm.).
I have to make 3 conductors to get app. 4-6 ohms.

Bernt "Båndsei"

 

[båndsei]

Now in action.
Sensivity a bit lower than the Aurasound they are replacing.
Sounds nice,crossoverfreqens changed to 1500hz.

Bernt "Båndsei"

 

[karellen]

Impressive
I have no words.

More pics, please!

 

[ApogeeLover]

Are those 'Neo' magnets you're using ?

 

[båndsei]

Yes ,6x10x70mm.

 

[ApogeeLover]

What did you use for the ribbon material on this last build?
It looks quite good for the job, as the pressed circles appear to give 'reinforcement' to the suspended strip..

 

[tecnofossil]

Now in action.
Sensivity a bit lower than the Aurasound they are replacing.
Sounds nice,crossoverfreqens changed to 1500hz.

Bernt "Båndsei"

You might want to consider adding a half sphere or perhaps a egg / bullet shaped diffusor at the bottom of your ribbon module to improve dispersion of the woofer at the upper end of its frequency range (like the Hegeman H1) That is a great job you did on your ribbon module. I'd love to hear the finished unit. Back in the late 70's I built an experimental cylindrical tweeter along the lines of yours except while yours uses true ribbons the one I built was a planar diaphram with vertically oriented conductors on a thin plastic film. Around the (cylindrical) magnet assembly was a thin sheet of open cell foam. The plastic filmwith the conductors was wrapped around the foam. When a positive polarity signal was applied to the conductor the whole diaphragm moved outward (expanding in you will). With the negative signal it moved inward (contracted). It was low efficiency and I wondered about how linear the expansion vs the contraction of the diaphragm was with the same level signals (due to the effects of the thin foam, the elasticity of the film diaphragm and the the diaphragm being mounted in front of the magnet structure is was really a single ended design). I never did too much with the tweeter after the initial experiments. My plan (if it had worked) was to use it to improve the high end of some Ohm G speakers (they look like a short version of the Ohm F....no paper section). Best of luck with your design!

 

[båndsei]

I use my favorite material alu/paper and i keep the paper.Alu is 7my.I am going to use a konusshaped difusor.

Bernt.