More Linaeum?

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Interested if anyone knows where I can get the Linaeum tweeters with the silk diaphragms. Know Aura Sound lists them (monopoles only, though) but haven't had any luck getting through to an actual person ... never mind having any one return my calls ...

Also ... anyone know about the fate of Impact Technologies and their "airfoil" speaker ... website seems moribund at best ... sort of assume they're out of business. Are these drivers essentially large "half" linaeums or am I way off base. (Anybody know a patent ###??)

Any thought/ info would be appreciated.

Thanks

Dan Brummitt
 
why not build a pair?

Dan: why don't you just build yourself a pair? These are just about as simple as it gets. You can use some silk screen fabric to make the diaphragms. You can snag a dead pair of Lineaum tweeters and change the mylar for fabric. Kite stores have rip stop nylon that would be light and easy to use. You could also upgrade the magnets for some neo units as they are easy to get and cheap. You could make a cylindrical unit with some light but springy film or cloth, make the diaphragm like a "C" fix one end and drive the other end almost 360 degrees! That's what MBL do. Hope you have some fun and report back. Hey remember the little flat circular tweeter that Arnie Nudell made out of a regular dome tweeter magnet? That's a snap to build too and it also sounds good. Fun projects for those with a little time and not much cash. You could do a little ring radiator version of that one with a flat disk neo magnet and a metal cup horn load the sucker and kick some butt. Regards Moray James.
 
Dan,

I didn't realize the silk Linnaum had ever come to be. Is it dipole or monopole?

I can't find it on the Aurasound site; do you have a link?

Also, what don't you like about the Radio Shack monopole Linnaum.

Several years back David Hyre (Dan Wiggins' partner) designed me a XO, and found that it measured very well and was very well-behaved.

It's also rugged; I mistakenly blasted one with a high level 70 Hz sine wave and it wasn't fazed.

Thanks
 
Moary,

Suspect you're right (about ease of building ... but do you think just rip stop nylon or silk would be an improvement over the mylar/polyproplyene used in the driver ... they talk about "treated" silk ... with what do you suppose?) ... but am intereted in extending the concept into midrange (and lower, for that matter) ... thus question about "airfoil" ... for this need patent info and I suspect several zillioin $$ and/or hours to investigate ideal diapghragm composition. This from everything i can gather, is a "bending wave" driver ...

Currently have two Optimus LX-10's per side ... one inverted over the other so that the tweeters are "stacked" "upside down" about 1/2" over each other ... have had some phase misgivings (ended up reverseing the contacts on one of the linaeums which seemed to give the best results... though not exactly satisfactorily... am fairly murky about just how the linaeums radiate sound and what "phase" amounts to ... e.g. wouldn't one side of the diaphragm ... left/ right not front back ... be out of phase with the other?) The net result of the stacking configuration is a set up that plays very loud ... requires drastic HF attenuation ... has the crisp sweet linaeum top end ... but otherwise a "shouty" mid range ..." (The LF is not as much in issue as I'm running bi-amped into subwoofers through an (old) audio control crossover/equalzer).


********
Noah,

Try this # at Aurasound: NTL25- 354-4A .. it's listed as a monopole with a a silk diaphragm ... as I say, they have been unreponsive ...

I like the Radio Shack linaeum ... what limited exposure I've had with it ...just always figure there can be something better ... presumably that's why were all here pecking away ... also see above questions re: phase and loudness.

Originally got interested in Linaeum drivers when I heard them at an Stereophole show in NYC about 15 years ago ... when they fielded a hybrid speaker that I thought got close to best in show ... although wasn't mentioned as a contender. The high end was superb ... and as I understand it, their diaphragms were "treated silk". Although I realize that 15 years is a long term for auditory memory ... my memory of the linaeum vs the RS had the former coming out on top.

What's tantalizing, of course ... and I assume I'm not alone here ... is the prospect of extending the sweetness and "quickness" of the linaeum design into the mid range ... thus questions in original post about "airfoil" design.

Regards and t hanks to you both for your posts,

Dan
 
DIY Linaeum

Dan: I don't think that you will need to spend a whole lot of money nor time to find out if the project has a future. If you think things through before you start and plan what materials will best meet your needs to achieve your goal. Silk screen fabric is made of mylar monofillament. This material is available in a wide range of thicknesses. If you think that you will need to damp the fabric you will discover how necessary that will be after building a unit with untreated fabric. There are all kinds of things that you can damp the fabric with. Ideally you want a viscous fluid that will not polymerize and harden over time. That said you dont need to worry about that to begin your experiments. Any number of oils can be tried to evaluate correct viscosity. Light weight grease lubricants would not harden over time such as white waterproof lithium grease. Such greases could also be doped with graphite powder to increase damping. I should think that density or weight will be of some concern but I don't imagine that it will be a huge concern.
This tweeter is one in which you are dealing with a traveling wave as opposed to a bending wave. There are lots of silicon fluids that you could use but I would experiment with readilly available liquids that you have on hand. For example liquid soaps or common oils or even pancake syrup. You need to find out what viscosity of fluid does the best job then you can decide on what material is the best choice for the job.
As for the diaphragn itself I suggested silk screening fabric as that has the same density that the commercial product was made from but since it is in the form of a fabric it will have far more internal loss due to fiber friction. You might also consider thin light tissue paper (the hard kind) and you could easilly stiffen and damp that with a light spray mist of krylon clear spray acrylic. That combination would yield excellent internal damping and be quite light. You could try the same trick with household aluminum foil and a light layer of spray paint. This might work very well but would be prone to handling damage. But hey its cheap and easy to rebuild if something happens to it. Play with some simple materials and see what results you can achieve. I am sure that you will learn a lot about tweeters and have fun doing so. Best regards Moray James.
 
Moray:

Thanks for the in-depth post as well as the French Linaeum Website .... with help from the google translator I've got a good (if somewhat disjointed) start.

Can you suggest other drivers which use the "traveling" wave approach as opposed to the "bending" one?

dstockwell:

Good luck with DIY electrostats but watch those volts! HAve you tried substituting the cone drivers in the Radio Shack units with something different, better ... doping the originals ... x-over mods & etc. Am sorely tempted to go after my LX-10s.

Regards,
Dan B.
 
wel

Dan: if you can find a set of Sumo Aria's or either of the Museatex Melior speakers (the small floor standers were the best of those two) you can have a flat planar that uses a point source driven panel. The Highwood Audio driver (uses in those speakers) uses a high strength tight gap motor assembly to drive a 1.25 inch voice coil fixed to the centre of the diaphragm. If you want to build your own you can use a very good mid driver motor and augment the top end with a tweeter. To get the bandwidth we had to use a lot of tweaks on the motor assembly. If you find a damaged set of any of the Highwood Audio speakers I can provide you with a new set of voicecoils.
I should think that a nice line source could be made with available neo magnets and some iron pole plates. If you took the Linaeum idea and uses some ferro fluil in the gap to help stabilize the voicecoil you would have a very nice driver. Play around and see what happens. I also think that a good 360'ish degree driver could be made with the same Lineaum idea with a slightly stiffer diaphragm formed into a cylinder with one vertical end of the diaphragm clamped and the other vertical end of the diaphragm attached to a voicecoil being driven like a single ended Lineaum. Hope that makes sence. Regards Moray James.
 
D Brummitt said:

dstockwell:

Good luck with DIY electrostats but watch those volts! HAve you tried substituting the cone drivers in the Radio Shack units with something different, better ... doping the originals ... x-over mods & etc. Am sorely tempted to go after my LX-10s.

Regards,
Dan B.

I really would not know where to start, I guess I could go over to the loudspeakers forum and start there, or open them up and take a look.
 
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