First Small true ribbon tweeter with ferrites and a transformer 

be sure to connect it correctly though, since i did not. with the autotransformer you share one lead with the pimairy, then the wire closest to the other one should be on the ribbon. how i made the drawing is correct. just when i test the tweeter i fliped one wire (thats why the ouput was high...... measuring les then 0.4 ohm haha when connected correctly is measures around 4 ohm nominal dut did lose my 8dB advantage ) i have barely enough output to match the woofer

THanks m8 1 we cant since it would need many turns, witch would hurt frequency response. an electromagnet seperately powered is possible though. but a bit expensive and bulky :( 2. Many of my ribbons are multi traces. it does not need a transformer at all if its a long one :) 3. I got plenty of Neo's but i tend to not use them if not needed price difference for big ribbons sky rocket when i use neo's. talking times 5 times the costs. 4. usually i keep around 1 to 1.5 mm from the sides. since the field is more even in the gap. the sides tend to have a peak in field stregth. in a multitrace ribbon we could counter this with having wider traces near the magnets making them eseentially less efficient there. so the ribbon would move as much as possible as a whole. 5. well i used some old teroids in this case. i could have used any for of transformer, but a teroid is rather simple to put a few windings on. and easy to adjust.

Cut it yourself? Mylar can be bought on eBay look for electrostatic loudspeaker membrane

@@joppepeelen awesome that’s it. Thanks

damned Jonas ur so right every time :) by the way i tried the different corugation methods.. the distortion is the ribbon but non of the corugations solved it :( using 12 micron instead of 4 did. at the cost of 6-7 dB :(

@@joppepeelen What distances in the design match up with that wavelength or ½ of 3.44cm? Could it be a torsional/wiggling issue? I wouldn't worry about the toroid core being iron, which is std. in the full range Speltz Autoformers - and also a beefy 1Kva toroid I am experimenting with - just using the secondaries in series measure well, also at higher freq. and has a desirably low DC resistance. However the winding number is much higher and there might still be skin effects to consider.

@@perh.nrgaard1813 Cores of toroid are so many types , is dificult to find the good one until he dont order one knowing specs. Is more efective to use a simple FeSi regular transformer core than feritte .Skin effect is not present in audio . Thanks

​@@iamwangine8752 Cores of toroids used for mains is for obvious (saturation /cost) reasons also with iron core's. The Skin effect is well documented and can be calculated, if making the wrong design decisions or using big mains transformers with large diameter solidcores (trying to keep DC resistance low) it can come into play also in the audio frequency band. I recommend to look into math before making any assumptions. As the saying goes in engineering "Assumptions are the mother's of all **ck-up's" ;-)

@@perh.nrgaard1813 well ,my english is not native and so good , but on first point about tranformers you confirm exactly what i write. In other hand about skin effect , man you are the single one i hear u involve skin effect in audio field. Sience was developed the differential amplifier we have so many chain distorsion 1000... times biger and harmful for our ears than "porly skin effect sucker " ,and at the end is not about assumtions is about facts andwhat we hear .In theory everything is applicable in real life is kinda different. Whatever , i wish you to continue believe about skin eff. Good day to you

hihi you might be suprised :) thanks for the Tip ! i got 4 rollers of 24 cm now and wating for a present to make it a 48 cm wide one :)

Resonance is not that important unless one crosses over at 50 hz ;)in this case i eyeballed it. The cores where where from old power transformers. They work fine. Its really not tgat picky sane as fir esl steo up transformers the cores usually dont have to be all that soecial exceot dpropiately large sependibg on how low you will use them ar what powr. In this case purely proof of concept. I believe i talk about turns used in the previois vidro where i made them. Been a while :)

The idea ti measure res should work indeed! Using a tiny weight might be easuer after you know where it will land with x amount of grams

i did a video about how to make one

@@joppepeelen Is this video you? ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-XTLFmuAIAwM.html

well it is not the housing of led lights, but if they work why not ! , be sure to take the ones without the deep fins :) another option is showed in the reply of jonas karud, i also used curogated carboard from an hobby shop, its flat on one side and corugated on the other

If you want fine corrugation, than you can try using straight cut motherboard distances for $5 a pack. The teeth are not perfect but a little work with a file and they work.

Why not 3d print?