DIY Planar Ribbon Speaker Line Array

Tom Levno

Tom Levno

New Member
Greetings Fellow Speaker Freaks and Music Lovers,

I was curious about how these ribbon drivers would work in a line array so I got hold of some and put 6 of them on the side of a chunk of 4" PVC pipe stuffed with fiberglass. Did a series/parallel arrangement to get close to 4 Ohms and drove it with a 400 Watt monoblock. The source was a CD player playing Diana Krall, Pink Martina and some other favorites.
The result: Female vocals are very clear and lovely with phenomenal detail. As expected, dispersion was wider than with a single panel and it filled my back yard nicely.
Of course there was little bass because these little panels have nothing to offer below ~200 Hz and I plan to cross them over at maybe 500 Hz. I'll be shopping for some woofer drivers to go with them. If it works out, I'll get some more and carve up another pipe and have killer stereo in the back yard.
These panels are the same as used for the tweeter in the Sangreal guitar amplifier. That amplifier is no longer made because the maker died last year and he was a one man show. I got the panels on ebay.
Array of 6 panels.jpg Sangreal Bafle View.jpg
Happy listening,
Tom
 
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If you plan on adding a woofer, I'd stick to 10" maximum with a 700Hz crossover point. Something that will result in a 4th order filter slope to protect the planar components. If you're unfamiliar with passive crossover design, maybe go with an electronic crossover like Beringer. Bi-amping is a good idea if it's in the budget.

By the way, those are probably planar drivers, not ribbons which operate on a different principle.
 
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Howdy Homebrew,

Good advise. I have an old Biamp crossover kicking around that I could use. I have designed and built a number of passive x-overs over the years. Biamplification is much easier but I like simple if it's going to live outdoors. I buried some nice fat wires in the backyard several years ago for eventual speakers and lighting. Finally getting around to it.

Yes, they are planar drivers, not folded ribbons.

Turn it up,
Tom
 
Tom, it sounds like you're well equipped to have some fun. One nice thing about using planar mids and tweeters is they have a ruler flat impedance that makes passive crossover design easier than your typical cone or dome driver.
 
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swechsler said:
Are those really designed for outdoor use?
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In response to your question, I don't think they are designed for outdoor use, but I also think they would probably stand a lot of weather. I plan to use them outdoors, but I'll probably make a little raincoat for them as well.
 
What's the size of the ribbon driver? It's very similar to my Monsoon FPF-1000 speakers, which use a 4X8" midrange. VMPS used the same Monsoon mid in their RM Series of speakers. An awesome driver, and if your ribbon sounds similar, they should make for great line arrays. Though, I wouldn't have the heart to relegate them to outdoor use. :(
 
Tom Levno said:
Howdy Homebrew,

Good advise. I have an old Biamp crossover kicking around that I could use. I have designed and built a number of passive x-overs over the years. Biamplification is much easier but I like simple if it's going to live outdoors. I buried some nice fat wires in the backyard several years ago for eventual speakers and lighting. Finally getting around to it.

Yes, they are planar drivers, not folded ribbons.

Turn it up,
Tom
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Most so called "folded ribbons" are actually AMT (Air Motion Transformer) variants. Since the original patent ran out everybody and their "brother" is making and/or selling AMT variants.

True ribbon drivers do not have pleats.
 
StimpyWan said:
What's the size of the ribbon driver? It's very similar to my Monsoon FPF-1000 speakers, which use a 4X8" midrange. VMPS used the same Monsoon mid in their RM Series of speakers. An awesome driver, and if your ribbon sounds similar, they should make for great line arrays. Though, I wouldn't have the heart to relegate them to outdoor use. :(
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Greetings StimpyWan,
The drivers I used are indeed 4" x 8".
The spec sheet is available here:
https://shop.speakerenco.nl/content/images/PDF/PFT150-50-3-AA.pdf
 
They are Planar Magnetic drivers. They may use the same technology Magnepan uses in their Quasi Ribbon speakers. That being, a foil ribbon is bonded to a Mylar diaphragm. There is a sheet of magnets on both sides of the diaphragm that produces push pull movement.

True ribbon speakers have no substrate. The ribbon itself is suspended between magnets.
upload_2021-9-29_19-46-7.png

Planar magnetic have a substrate that the conductor is bonded to. They also have magnets in front of and behind the diaphragm. That makes for push pull (double ended) operation. Some planars have magnets only on one side, ie: single ended.
upload_2021-9-29_19-47-46.jpeg

If it has pleats or folds it's an Air Motion Transformer.
Air-Motion-Transformer-Prinzip-HEDD.png
 
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I use those Monsoons with a Monsoon sub as my everyday computer speaker.
When I want to take a break from the screen I can cue up some favorites, sit back and pretend that I'm in the control room with the mixer. Incredible detail and musicality. I got that in the back yard but louder and more uniform coverage. Still looking for the right woofers. Might go with something made for car audio so it will stand up to the weather.
 
Those are the Sonigistix/Level9 planar drivers used on some Monsoon speakers. There was a slightly different version used in some earlier Monsoon speakers like FPF-1000. Level 9 was purchased by Eastech which these were probably made by.
They were designed by Dragoslav Colich for Level 9 using technology licensed from Bruce Thigpen of Eminent Technology.
VMPS used this exact driver with a slight mechanical change to fix a reliability issue where the rivet attaches the connection to the planar. They cut the rivet out and replaced with a screw, nut and washers.
Hope that helps.
 
getdadams said:
Those are the Sonigistix/Level9 planar drivers used on some Monsoon speakers. There was a slightly different version used in some earlier Monsoon speakers like FPF-1000. Level 9 was purchased by Eastech which these were probably made by.
They were designed by Dragoslav Colich for Level 9 using technology licensed from Bruce Thigpen of Eminent Technology.
VMPS used this exact driver with a slight mechanical change to fix a reliability issue where the rivet attaches the connection to the planar. They cut the rivet out and replaced with a screw, nut and washers.
Hope that helps.
Click to expand...

Both my FPF-600s and FPF-1000s use the earlier generation panels. I'm not sure if the sound quality is much different between generations, but my panels have 8 openings across, where later panels have 13 openings. So, dispersion at least has to be better on later panels. Still, my Monsoons sound very good, and the VMPS speakers I've heard were fantastic. No losers either way.
 
StimpyWan said:
Both my FPF-600s and FPF-1000s use the earlier generation panels. I'm not sure if the sound quality is much different between generations, but my panels have 8 openings across, where later panels have 13 openings. So, dispersion at least has to be better on later panels. Still, my Monsoons sound very good, and the VMPS speakers I've heard were fantastic. No losers either way.
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I think that's right. I have listened to panels made by several manufacturers of this general size and have found them all to be amazingly clear and musical. They work best if they are not fed signals below their midrange best, which coincides with the female vocal range where they sound very natural.
I would warn folks against DIY opening of the panels to replace rivets with screws because the magnets can be dangerous flying objects. Without the well designed jig, it's risky business.
 
StimpyWan said:
Both my FPF-600s and FPF-1000s use the earlier generation panels. I'm not sure if the sound quality is much different between generations, but my panels have 8 openings across, where later panels have 13 openings. So, dispersion at least has to be better on later panels. Still, my Monsoons sound very good, and the VMPS speakers I've heard were fantastic. No losers either way.
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Agreed! In this case you don't have to open the driver to change rivets out for screws. They are exposed at the bottom.
There's info over at Audiocircle on it.
https://www.audiocircle.com/index.php?topic=113470.60
 
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