Building a field coil FR driver

[Magura]

We have been discussing to make the basket of either glass or carbon fiber. Any reason why that's not a good idea?Magura

Anyone???Magura

[stein]

Carbon fiber, not glass fibre. Optionally, use carbon sock (similar to "snake skin") around glass fibre rope (should be available in .dk, it's used for reinforcing large but thin surfaces made of thin glass fibre textile - gives strength without adding unnecessary weight and complexity...)However, if you plan to vacuum mould it (de pressurizing), you can probably go with glass fibre...edit: do not forget to prepare parts from metal on structurally critical points/positions where thread has to be and to mould them inside. Neither epoxy or poly like holes with threads inside, neither strong enough, neither durable. But that shouldn't be a problem for ya, cwazy metaldanske

[Magura]

Magura

[Magura]

edit: do not forget to prepare parts from metal on structurally critical points/positions where thread has to be and to mould them inside. Neither epoxy or poly like holes with threads inside, neither strong enough, neither durable. But that shouldn't be a problem for ya, cwazy metaldanske

I figured that molding in a big washer would do for this? How do you work around this on the trikes?Magura

[stein]

I figured that molding in a big washer would do for this? How do you work around this on the trikes?Magura

We don't do it with pressure, additional steel or aluminium reinforcing points are moulded between layers. A washer can help. The main point is to create relief for stressed points. Glass fibre will hold, the epoxy itself is what cracks under stress.

[Zen Mod]

paper cone ...... please ?

[stein]

Cone should be paper. Basket, whatever. Aluminium (non-magnetic) baskets are better because small metal fragments don't stick to it. Steel baskets are much cheaper for mass production.

[michabass]

Hey Mr. Magura, this is a very intriguing thread you've got here!

Any ideas on the cone material yet? Presume it would have to be paper for its natural sound? I guess the basket material isn't a very critical item in this early prototype phase? You plan to build everything from scratch or use any scrap parts from old spkrs? You found the iron for the polepieces?

So many questions! Ill be watching this thread with a lot of interest...

edit:

[Magura]

paper cone ...... please ?

Hmm, but using carbon I could make a lighter cone, and dampening should not be an issue, if the right resin is chosen. Making paper cones is somewhat harder from where I stand, as carbon is a material I'm very familiar with.Why should it not be possible to make carbon act like paper?Magura

[Magura]

Basket, whatever. Aluminium (non-magnetic) baskets are better because small metal fragments don't stick to it. Steel baskets are much cheaper for mass production.

Making a basket from metal, would be much harder than making it from carbon or glass fiber, hence the question. Making a mold for a fiber basket, is a walk in the park, opposed to machining metal baskets.Magura

[Magura]

Hey Mr. Magura, this is a very intriguing thread you've got here! Any ideas on the cone material yet? Presume it would have to be paper for its natural sound? I guess the basket material isn't a very critical item in this early prototype phase? You plan to build everything from scratch or use any scrap parts from old spkrs? You found the iron for the polepieces?

So, to answer your questions (hey, I'm the one whom should receive answers here ).Cone I hope to be able to make from carbon fiber, to save some weight, which I can then spend on the voice coil (make it more powerful). I still am not convinced that the material properties of paper, can't be transfered to carbon. (beginning to sound like helicopterboy, I know ).I plan to build everything from scratch, as that's most likely the easy way in the end. If using parts from other speakers, it will end up with a lot of compromises. Not my cup of tea.I am sure going to make the pole pieces myself, as no other would fit the bill, since the plan is to make a very strong magnet. My calculations so far, has ended up at 4kg of magnet wire per magnet, so the motor alone will end up around 10kg. This is only limited, by the fact that there is a limit to the diameter (can't be bigger than the cone diameter) and the length can't be bigger than it still fits a BIB speaker.No pics so far, but if I can get my feet back on the ground (chances are that it can happen tomorrow afternoon), we expect to have something to show in a few weeks.I think I better repeat my old mantra: It will be ready by Christmas Magura

[stein]

Why should it not be possible to make carbon act like paper?Magura

Carbon should be your choice if you DON'T WANT it to act like a paper cone. At the end, it's not the carbon that would scare me off from doing it, rather the tar, that is, the epoxy resin (I presume you wouldn't fiddle with the crappy polyester resin)To get out the best from the carbon cone, you'll need a proper two or three part mould and a sufficiently well made pressurizer to press out all the excess material to keep the final cone weight down. At the same time, will have to take care about heating of the resin with the hardener to avoid air bubbles and deformation, but I guess you already know that. Doesn't it make you wonder why there are very few carbon coned speakers on the market? Think about why many rather work with Kevlar...

[Magura]

Oh, this is much closer to the answer I wanted to hear Making a heated mold, use it in a press = a walk in the park. Making a paper cone = no friggin clue, lots of gray hairs.I was actually thinking pre-preg carbon. It's nice and easy to deal with.I don't quite catch your last comment. Why is it they don't use carbon cones? I dared to assume, it was due to production cost?Magura

[Zen Mod]

point is in fookin speed of sound in cone ;dunno why - but nature of directly emanated sound from cone , mixed with secondary part of wave traveling through cone - seems that these two - in paper cone are somewhat most natural to our ears .my ears , WTF !anyway - I can't prevent you from making cone you wish , but ...... "plastic" basket - clever ..... I have a pair of ancient Cabasse FR with red plastic basket ; I like them further - nobody can prevent you from making magnet assy bigger than basket - if you prefer mounting of driver from back side of speaker baffle

[stein]

I don't quite catch your last comment. Why is it they don't use carbon cones? I dared to assume, it was due to production cost?Magura

http://most-expensive.net/speakershttp://thehottestgadgets.com/2009/07/the-10-coolest-and-most-expensive-speaker-systems-money-can-buy-003939http://www.higherfi.com/spkrlist/speakerlist.htmDon't you find it just a bit strange or at least odd that none of the most expensive speaker systems in the world has 0 (read: zero) carbon cones on their drivers, or at least, on a single driver? Production cost is to be dissmissed in this case.This one seems to be one of the few examples that it's possible... http://www.proac-loudspeakers.com/carbon8.php but then... most of the results you'll google out will get you to relatively affordable and/or inexpensive products...Still, no reason not to try...

[Zen Mod]

Metaldanske I resume that you're keeping eye on already known thread http://www.diyaudio.com/forums/feastrex/70709-exciting-new-line-fullrange-drivers-feastrex-91.html#post1975835edit also their blog http://shinshu.fm/MHz/06.94/archives/0000302406.htmlgoogle thingie :http://translate.google.com/translate?u=http%3A%2F%2Fshinshu.fm%2FMHz%2F06.94%2Farchives%2F0000302406.html&sl=ja&tl=en&hl=en&ie=UTF-8

[Magura]

Thanks :cheers:For once I actually did catch the pics at Diyaudio myself.....I promise that won't happen again For now, we are still working on the molds, but if we keep the pace, this WILL actually be ready for the Danske BAF Magura

[Zen Mod]

........For now, we are still working on the molds, but if we keep the pace, this WILL actually be ready for the Danske BAF Magura

OK - so just let's hope that both - Serbian and Froggy Terrorists will arrive .....

[Magura]

OK - so just let's hope that both - Serbian and Froggy Terrorists will arrive .....

Yeah, that could be rather good fun. Magura

[Zen Mod]

Matrice and Patrice -- how to translate that in Engrish ?anyway - molds - Male & Female parts

[Zen Mod]

furtherspider test - used paper napkin :fouetaa:these 9 pics - molds for cone/former combo , whizzer ,spider , surroundI believe Metaldanske will make molds for baskets these days ....... I'm just fookin pic's resizer

[michabass]

Now that is something else!!! Molds look awesome!