A DIY Ribbon Speaker of a different Kind

[moray james]

no real need to re invent the wheel here as you are for all intent building a Lineaum. See what worked and was practical in a real production product. Once you build one you can optomize materials all you like.
I still think the a light syntheric woven fabric is a very good choice for the diaphragms as the weave will provide energy loss and self damping to structural resonances. Polyester silk screen fabric would be my first choice. In the Lineaum design the diaphragm is a soft lossy material not mylar as many have claimed. So my suggestion of a polyester woven fabric light but lossy. A fabric could even be viscous damped with silicone fluids. An almost 360 degree version could be built with a single loop of fabric diaphragm clamped at one end and driven at the other. Just some thoughts. I cannot help but think that all of this would infringe on the Paddock patents if someone was considering a commercial endevour. Google them up they are full of good information.

[tinitus]

Yes, yes and yes

But I do believe the only real genious trick with the Rubanoide design actually is exactly the tension in the diaphragm, which correctly adjusted on its sides, will keep it in place

No doubt, there will most likely also be all sorts of ressonance problems
But wont that the same issue with any other ribbon, planar, ESLs the famous Manger, or Lowthers etc

[amp-guy]

Here is what I was thinking of for the V.C. Digikey has this sfuff in stock in up to 18" precut (cheap) or 500' rolls ($$$) I have used this stuff before but not to make a lineaum, it is copper it will solder or there are very solid reliable coonectors. it is polyester so adhesives and resins will bond effectively.

http://www.parlex.com/tech_library/ps-2562.pdf

actually the stuff is fairly stiff, and less mass than an etched frp
glass pcb..
I have wondered why every effort to put a lineaum driver on the market seems to fall flat . I have a set of the old Rat shack Lineaum tweeters laying around that never fail to impress when I have hooked them up, but I feel the real potential lies in a full range driver.

[moray james]

The suggestion for the polyester silk screen material is also partly because it is able to hold itself up and weighs less that a solid film which would be able do the same and also be as lossy. This design is not the same as a planar one in which a very thin film is used under tension. Structural resonances will be similar to those of a cone design but there is no diaphragm termination over most of the diaphragms exposed edges so resonance is a big issue and hence my suggestion of a woven fabric (one in which the weave permits equal motion in both directions,length and width). Termination or suspension is a rolling type as in the Lineaum. So there will be considerable reflection there and as I said zero termination along the top and bottom edge of the diaphragm foil. Perhaps a damped structure could house the "loose edges" of the diaphragm and minimize that problem?

[tinitus]

Why no commercial...

Well, theres lots of fine designs that doesnt last long as commercial units, even some of the finest kind

Might be due to all sorts of things
Stability issues
Demands fore frequent adjustments
Production problems
Quality issues
Proper material fore crutial parts missing
Lack of proper attractive design
Looks too much like prototype
Too few potential customers
Only function in specialised arrangement
No dealer network
Price
Looks
Lack of financial interest
No investors

[amp-guy]

LOL that about covers it doesn't it
Maybe add just plain poor buisness practices.

[tinitus]

I know we should really stay away from the very strong neos

But I really do think they are essential fore this
Or at least, I dont think I will bother with it otherwise

As I can get quite stubbern some times, I have found an almost safe way to assemble the magnet/pole unit

Magnet I would like to use is 2"x1"x3/4" N50, pulls 142pound, quite hefty fellow
Theres also a 1"x1"x1/2" N50, pulls 58pound, and much easier to handle
Or maybe alternatively consider disc magnets

All magnets should be placed several meters away from the unit to be assembled
My guess is that 1 meter is not safe enough, as they may very well come flying like rocket

Every magnet handled should be marked carefully
Polarity is best found with a small magnet, of which you have marked polarity also

When handling a magnet its best to have a tight grip of the thing
But not when placing it, best to let it go if one cant hold it

Pole unit should be firmly secured, before placing any magnets are placed

A wooden plate could be placed between magnets when placing the first row of magnets
That way the magnet to be placed wont be able clash together with previously placed

A wooden stick and hammer might be needed to get them lined up perfectly

To get the remaining poleplate in place is best explained by the drawing below
Threaded rods with nuts(8mm) are used to control this exstremely dangerous part
One poleplate should have threads fore the rods

Still great risk of something unpredictable and very bad could happen
So all fleshy parts should kept on a safe distance at all times

[neededandwanted]

Did you get a good look at valvitude's frame/magnet assembly on his tall ribbons over here?
A 60" Ribbon w/TL Loaded Extremis Hybrid

He used threaded rods and a strong custom built stand. He also used superglue on one side and epoxy on another side of each magnet.

These huge Neos just scare me with their bone-crushing power.

Makes me want to re-try those electromagnet calculations again. Yikes!

[a.wayne]

Crazy glue will not work , use a good epoxy 2-3 hrs drying time is typical ..

[neededandwanted]

Originally posted by a.wayne
Crazy glue will not work , use a good epoxy 2-3 hrs drying time is typical ..

I think he was primarily using the crazy glue to hold the magnets still while the epoxy was setting.

In any case whatever he did completely worked in a very tall ribbon with big Neos holding a 20mm gap.

I have seen others on this forum using only crazy glue.

Why do you say it won't work?

Personally, I can't get it to work even in applications that call for it specifically, like keeping a rear view mirror attached to a windshield in a car. Those kits come with 2 bits of cleaning liquid (alcohol and acetone) so I am guessing that some of the crazy glue failures are in surface prep.

("crazy glue" = "super glue" = cyanoacrylate based fast-acting glue -- I am not sure if the brand names are used outside the US)