It's was an Espanex flexi circuit material i used for the ribbon.
http://www.nscc.co.jp/english/materials/index.html
http://www.nscc.co.jp/english/materials/index.html
I was thinking of using the following:
http://www2.dupont.com/Kapton/en_US/products/FN/index.html
25 micron Kapton + 5 micron aluminum foil should make a decent enough ribbon.
Don't the magnets push each other apart?
http://www2.dupont.com/Kapton/en_US/products/FN/index.html
25 micron Kapton + 5 micron aluminum foil should make a decent enough ribbon.
setmenu said:
Don't the magnets push each other apart?
Spasticteapot said:
try looking for AC 121200EM : http://www2.dupont.com/Pyralux/en_US/assets/downloads/pdf/ACclad_H-73247.pdf
http://www2.dupont.com/Pyralux/en_US/tech_info/index.html
It was Dupont stuff i started with.
No the magnets don't repel if you have sufficient mass of pole piece.
I just had a bit of an idea: Since headphones require so little power, what if a huge stack of resistors were placed in series with "straight" ribbons along with an impedance compensation network? This would be massively inefficient - by my math, a headphone transducer composed of six 1/4" x 4" ribbons wired in series would result in 0.2 ohms DC. If wired in series with a further 3.8 ohms of impedance, about 5% of the amplifiers' power would actually go to the headphones, allowing an ordinary audio amplifier (20WPC+) to drive them with ease.
Please see attached picture to see what I'm thinking of.
Please see attached picture to see what I'm thinking of.
Attachments
setmenu said:
It looks like you could modify the design a bit to use the diaphragm from a HiVi RT1 or a similar small planar. The thinner traces and lighter weight backing would increase the efficiency, and there would be a much smaller magnet gap that would also increase efficiency. The down side of using the RT1 diaphragm is that the surface would be more rectangular--something like 2" by 3/4". However, you could just use part of the diaphragm and fold over the unused section. You could also stack two of them side-by-side.
Of course, this raises the question whether the smallest BG tweeter could be used as a headphone element. Might be worth an experiment...
Spasticteapot said:
A commonly quoted thickness for a "typical" planar diaphragm is around 12 microns for the aluminum traces and 12 or more microns for the backing. Or, about .5mil for each. It turns out that kitchen foil is about this thickness. You can buy .4mil polyethylene at Lowes, and with a layer of spray-on or brush-on adhesive you can make a diaphragm that is very cheap. That's what I did many years ago for those DIY Heils that were written up in Audio Amateur.
But I wouldn't bother--because I think you can use the diaphragm from an RT1 or something similar and get better results.
Having just completely rebuilt my Magneplan SMGa's, I suppose that construction technique could apply to headphones rather easily. It takes some preparation to lay out the 2 foot runs on the speaker by hand....
I have lots of Al wire remaining from the repair kits, although one might use super fine stuff from any source if you are willing to experiment. Contact adhesive is cheap, and one doesn't need many magnets. There's also the chance to experiment with diaphragm material, resonance damping etc...
Just a thought,
Ed
I have lots of Al wire remaining from the repair kits, although one might use super fine stuff from any source if you are willing to experiment. Contact adhesive is cheap, and one doesn't need many magnets. There's also the chance to experiment with diaphragm material, resonance damping etc...
Just a thought,
Ed
How about using some of the Apex Jr tweeters - if you gathered 4, you could build 1 pair of headphones - they have a spiral wound transducer, and a single perforated magnet - you need to switch the back planar magnet out for a perforated one, but hey thats a minor technical challenge 
Just a thought
Owen
Just a thought
Owen
From scratch? No, but we have used dipole versions of the SFI tweeters sold by Apex Jr., driven full range, to make headphones.
Doing a proper printed-circuit diaphragm would not be easy or cheap, but with a pen/marker loaded with conductive ink/paint you could draw a serpentine voice coil on some bo-PET (Mylar), hang it ribbon style (free to swing in the middle) and sandwich it between two perforated magnets (upgraded rubber fridge magnets, like the ones Wharfedale used 40 years ago) as a proof-of-concept. The efficiency would be terrible, but so what?
Doing a proper printed-circuit diaphragm would not be easy or cheap, but with a pen/marker loaded with conductive ink/paint you could draw a serpentine voice coil on some bo-PET (Mylar), hang it ribbon style (free to swing in the middle) and sandwich it between two perforated magnets (upgraded rubber fridge magnets, like the ones Wharfedale used 40 years ago) as a proof-of-concept. The efficiency would be terrible, but so what?
Thread moved to Headphone sectionI cannot wait anymore for the new transmission audio headphones. I don´t like the planar lcd-2. They don´t have highs as good as my speakers who have a true ribbon fountek 3.0. The owner of the company said that they will cost less than electrostatic headphones, but I wonder what electrostatic headphones he´s referring to...