Dipole creation information sought!

[geolemon]

I did a little searching on this forum, and I'm surprised that I didn't come up with much regarding dipole fundamentals... the foundation I need to start playing.

I had some experiences with some Martin Logan Clarity loudspeakers, and I loved them.

Sure, part of why I loved them may have been something inherent in the ESL panel's acoustics...
But part of why I loved them may have been something related to their behavior as dipoles.

I loved the manner in which they filled the room with sound... they were not directional. This is great for someone like myself who can't sit still.
Possibly this didn't have to do with ESL or dipole, but rather the curved shape of the ESL panel, and it's dispersion.

I want to start playing with dipoles... learning hands-on.
I'm even intrigued to create a curved dipole, with small full-range speakers (such as Aura's Cougar 2", or some Tang Band 2" drivers Parts Express carries) firing at different angles... or a compound dipole... I have some ideas.
Just looking to see if I can essentially replicate the Martin Logan's ability to fill the room with sound, in a non-directional manner, using a more simple dipole.

I'd like to learn more about dipoles, the advantages and disadvantages, their properties, etc.

My knowledge of them isn't missing completely:
I do understand that they exist on a baffle. As long as the wavelength is smaller than the baffle (er, distance from speaker to edge), then no cancellation. For frequencies whose wavelength exceeds that distance, they begin to cancel, rolling off at some rate.
So, for a dipole to yield a smooth response, I understand some EQ must be employed.

I want to start playing with this loudspeaker design.
If anyone can point me to some threads, or sources of information on dipoles, I would greatly appreciate it!
Fundamentals, pros and cons, and particularly how to design that EQ circuit.

Thanks in advance!

[HeatMiser]

Linkwitz has a lot of detailed information on his site. It isn't the most well-organized source of information in the world, so do poke around a bit.

On the other hand, our own Kuei Yang Wang seems to think that Linkwitz (and most of the rest of the world) is going about it in entirely the wrong way. He certainly acts like an authority on the subject; you might do well to search up some of his posts, read and make up your own mind.

[AndersZ]

Linkwitz has a lot of detailed information on his site.

Not any more sadly,

Most of the detailed information has been taken offline but can be bought.

is going about it in entirely the wrong way

Maybe not so surprising, I don't really agree. By using a big baffle one of the biggest points in using a OB speaker is greatly reduced. The figure of 8 radiation pattern is started at ~150Hz instead of 500Hz, so the room influences much more up in frequency. I would't either want such a big radiating panel or use heavy 8" as tweeter, but that's more my personal taste.

I'm even intrigued to create a curved dipole

In my experience I don't think that's necessary. The sound will fill the room just fine with flat baffels.

However, these are just my point of views

Anders

ps. Geolemon: You might want to check out my homepage, I don't have so much technical information on dipole models but you might spot something you haven't seen before.

[catapult]

Much of Linkwitz' older stuff is archived online. As noted on SL's page, he was exceeding his bandwidth limit causing the site to shut down. That's why he removed many of the pages, not to try to make money selling CDs. So you can buy the CD or go to the archive site for which he provides a link.

http://web.archive.org/web/200306121...nkwitzlab.com/

[454Casull]

Has anybody actually built a pair of Orion speakers?

[Timn8ter]

Drew Eckhardt built the Orions and posted a picture in the permanent systems thread. Here's his website.

[geolemon]

I appreciate the comments!

I actually checked out Linkwitz's site pretty thoroughly, at least with regard to the Orions...
I had checked out Seas loudspeakers (and got a personal walk-through of the Klippel Distortion Analyzer by Dr. Wolfgang Klippel himself! ), and I'm more intrigued than ever to hear their drivers.. particularly the Hexadym tweet. They did have a disassembly of it there you could check out the chassis and componenets... definitely looks simple enough to ensure that much of the price goes to profit..

Anyway, I had been to his site in the past, linked to tech documents from here or there... but I haven't read any of his whitepapers on dipoles, if there are any (I'm sure there are!).
I'll be checking those out as I can.

And, I'll be keeping the baffle size in mind as I read... interesting to at least note that there is controversy regarding it. Certainly makes it more of a variable to play with myself.

My previous thought (pre-dipole-concept ) was to build a line-array, using little full-range drivers that would allow me to get away tweeterless... the Aura Cougar 2" full-range is good to about 18K, down to about 250hz... that's pretty darn good.
Hi-Vi also makes a really decent looking mini-fullrange, another 2" with a dished cone, for just a tad less money.

My thought with the curved baffle would be that I could use a matrix-array of these tiny drivers on maybe a panel with two angles, three surfaces, maybe 15 degree angles or something.
And I could compare it to the same deal, but a flat baffle.

Just ideas to play with... but I obviously need to learn some fundamentals first!

Does anyone have any information, in the form of a generic "how to design it", for the EQ circuit?
I saw a schematic on Linkwitz's site, but it was specifically for the Orion system. (I'll search his site a little closer... he may have a more designer-oriented whitepaper on there)

I imagine the EQ deisgn is going to tie to baffle size.... which dictates where the 6dB/octave rolloff begins, correct?

[geolemon]

Originally posted by AndersZ
ps. Geolemon: You might want to check out my homepage, I don't have so much technical information on dipole models but you might spot something you haven't seen before.

Thanks, checking it out now.

Very intriguing projects... I can see myself adding these exact same projects to my web page soon!
These are right up my alley...

I'm very interested in "gainclones" as well... only have heard about them since I started checking this place out, actually.

There's a subject that I'm afraid of diving into a forum filled with electrical engineers... of which I'm not!
(I did have a year of electrical engineering as a major in college.. but got scared after realizing I was in a classroom filled with guys who had been building Heathkits and Velleman kits since they could hold a soldering iron, and was therefore at a major disadvantage)
Any thoughts? Should I be brave?

[tg3]

Here are some useful dipole links.

* Steve Dodd's Dipole Speakers

* Big Baffle Development Page

* The RD75 Dipole Baffle Study

* Subwoofer DIY Page

[AndersZ]

but I haven't read any of his whitepapers on dipoles

The closest you come is his dipole design models: http://web.archive.org/web/200306120...com/models.htm. These are the ones that I thought were offline nowadays (although I've saved them to my HD...), great page with step by step how to construct the EQ.

Any thoughts? Should I be brave?

Of course you should That's how I do it...

Anders