Planar-magnetic drivers, and SDA?

nooshinjohn · April 2012

Just in the planning stages for my first DIY speaker project, and have been kicking around the idea if using planar-magnetic drivers for midbass, a 6 foot tall ribbon tweeter, and a powered sub for the bass. The general concept has two mid-bass panels per speaker, one on each side of the ribbon tweeter. Think Carver AL III with Magnepan serving up the midbass. The outside panel would be the dimentional array... I realize I have much to learn here and these are just a thought at the moment, but I just cannot get the idea out of my head that if a speaker could give you that open, transparent sound you get from a Maggie, with the three-dimentional presentation and authorative bass and soundstage from the SDA, it may just be a perfect speaker.:cool:

There is much talking out my **** in this post, but that is where all ideas start... what do you guys see as problems with the concept and how whould I overcome them?

heiney9 · April 2012

Since you don't have any experience building speakers nor are you an engineer nor do you have proprietary info about SDA's, you will end up just pissing in the wind. Ben60626 comes to mind.

Good luck

H9

nooshinjohn · April 2012

That was my thought as well Brock... for me it is still an interesting question though.

heiney9 · April 2012

Certainly theoretical discussion and ideas can't hurt, but that's a far cry from actually assembling and making it work.

skrol · April 2012

"Ben" ... Now, that's a name I've not heard in a long time. A long time.
Luke: I think my uncle knows him. He said he was dead.
Obi-Wan: Oh, he's not dead... Not yet.
Luke: You know him? ...

tonyb · April 2012

You sure aim high for a first time speaker build. Your going to need some kind of help getting all that to work together. I'm thinking pace first. Maybe have a chat with others on a DIY forum who might have tackled complicated builds before. I would aim alittle lower and concentrate more on quality parts that combining different sounds.

Peter over at PBN has a kit I think, with many options and degrees of parts to use. Looks kinda like a Watt Puppy if you ask me. Jim Salk would be a good person to chat with too and is more accessable over at Audio Circles. One things for sure, I wouldn't even take up that task without getting in the heads of some smart speaker builders first.

heiney9 · April 2012

I will say right off because of the extreme directionality of planer and electrostatic type drivers, creating aany sort of wide dispersion pattern will not be possible, aleast passively. Maybe electronically with the right algorithms ala the Surround Bar type of technology.

VR3 · April 2012

Hmmm, VMPS disagrees with you on that.

I believe they accomplish it through a waveguide

skrol · April 2012

I agree with TonyB. Having designed a built some simple 2-way bookshelf speakers (some ok, some not), it is not easy to get it right. Don't get me wrong. I think that there is much to be said for DIY and I long to DIY more speakers some day. You can learn a lot and it can be very rewarding. You just may want to take it a bit slower.

Computer programs and calculations can be a guide for the cabinet design but there is much more to making it sound right. Shape matters, materials matter, placement of the drivers matter, etc. Crossovers are more than just high-pass, band-pass and low-pass filters set to specific frequencies. Phase matters. Impedance of the system matters. PSpice programs can help in the design but good luck finding models for the specific drivers. In the end it comes down tweaking the voice of the speaker by a skilled ear.

VR3 · April 2012

http://www.vmpseurope.com/vmps-patented-cdwg/

heiney9 · April 2012

VR3 wrote: »

Hmmm, VMPS disagrees with you on that.

I believe they accomplish it through a waveguide

Ok, I wasn't clear in my statement, I was referring to a DIY noob, not a professional speaker company with many, many engineers and $$$ and time for R&D. My entire point is to accomplish what Noosh wants is probably not going to be possible since HE really has no background or experience building speakers, let alone something as "outside the box" as what he's describing.

I can change the plugs and oil in my car but that doesn't mean I can build a race motor to compete at the track. Maybe I can, but most likely I can't even know where to begin unless I have some background and experience building motors, etc. That was my point.

H9

VR3 · April 2012

Gotcha!

heiney9 · April 2012

I think it's an intriguing idea, because that could meld the best of both types.

It seems I touched on that with Matt Polk at the last HQ fest and he said something to the effect going forward it would be about a passive and active approach having better results because the active approach solved a lot of the limitations (or rather could) of the strictly passive approach. But both were needed if he (Polk) was going to do a new SDA speaker. His words were about SDA's future in general not specifically about ribbon and planar drivers.

Of course that was before retiring and Directed taking the reins.

nooshinjohn · April 2012

Thanks guys for taking this one on... H9, the idea I had was to also use a combination of passive and active technologies to bring them together, with the passive part being the planar drivers and how all 4 panels would relate to the other... basically the sda part of things, but active to meld the different drive groups together. I am going to spend some time getting my learn on about the different technologies, but I am of the belief that it can be done, should be done even. I think this combination has the potential to be amazing, and I think there are enough brains in this group to do it.

tonyb · April 2012

If thats the case John, your either in for a world of disappointment, or heavenly bliss, all depends on your blood pressure meds.

heiney9 · April 2012

It took Matt and another engineer 7 years to develop and implement the DSP algorithms for the Surround Bar, and they have doctorate degrees in the field. So knock yourself out

nooshinjohn · April 2012

Lmao...

Joe08867 · April 2012

Sounds similar to the Apogee Diva speakers I had. The sub is the only real difference. And I did use a sub with them. Actually dual subs set relatively high at about 100hz if memory serves. I used an active crossover to block anything above 80hz from the panels. Worked like a charm and had a huge soundstage for panels.

heiney9 · April 2012

So we have gone from SDA's to huge soundstage?

I have heard speakers with a huge soundstage, however they didn't replicate everything SDA's do. I don't doubt with certain well established manufacturer's of panels and electrostatics that a large soundstage is possible. I personally haven;t heard it, but then my listening experience has been with several Maggies (all properly set up), Martin Logans and a couple pairs of Sanders Sound ESL's all properly set-up. In every case just moving my head a few inches collapsed the soundstage. I have heard Carver Amazings as well, again a little movement and you are out of the sweet spot.

H9

Joe08867 · April 2012

I guess I meant huge soundstage in comparison to other panels of the time. This was many moons ago.

Nothing I have really listened to have had the soundstage of SDA's. Especially 4.1tl's.

That is also why I still own the SDA's and not the panels.

newrival · April 2012

heiney9 wrote: »

So we have gone from SDA's to huge soundstage?

I have heard speakers with a huge soundstage, however they didn't replicate everything SDA's do.

What do you feel SDA's do better than other speakers, other than a wide soundstage? not rhetorical, just curious.

evhudsons · April 2012

It's not neccessary the size of the soundstage for me but the quality and accuracy of playback along with extremely pleasant music. One of things that sold me back in 1989 was the salesperson playing other high end speakers, and then the crs, then the crs with the interconnect. He showed me how the stereo image opened up and stayed quite distinct and profound no matter where you were in relatin to the speakers as long as I was somewhere in the middle.

I wish I had the resources to try nooshines idea. If you were to do this you will most likely need toolfan, DarqueKnight, gimpod, h9 and others to help if you were not going to buy a speaker company. It is a neat idea.

Face · April 2012

heiney9 wrote: »

I will say right off because of the extreme directionality of planer and electrostatic type drivers, creating aany sort of wide dispersion pattern will not be possible, aleast passively. Maybe electronically with the right algorithms ala the Surround Bar type of technology.

It depends on the width of the panel more than anything else. A narrow panel can have very wide dispersion, but may not have the LF extension of a wide panel.

Waveguides are used to control directivity(dispersion) and properly designed, can increase LF extension. They're not for increasing dispersion per say, but matching it to other drivers or purposely creating a narrower beam that will interact with the room less.

The easiest way to go about what John is proposing would be to use four of these: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-706 crossed around 250hz, MiniDSP's for crossovers, 1-2 high quality woofers per speaker, and 6+ channels of amplification.

SCompRacer · April 2012

Face wrote: »

It depends on the width of the panel more than anything else. A narrow panel can have very wide dispersion, but may not have the LF extension of a wide panel.

Thats where a well designed, properly powered (2400 + total watts on tap) active crossover ESL hybrid comes in and saves the day.:cheesygrin: I also damp much of my rear wave which makes the sweet spot even smaller and more exciting, to me anyway. However, I'll take that small area as to me it sounds better than other wide dispersion speakers. And I have owned stock and modded SDA's and heard just about every model of them in treated and untreated rooms. Including a nice pair of modded 1C's that made there way through here before selling them to someone I know.:cheesygrin:

Planar-magnetic drivers, and SDA?

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