Push Pull Ferrite Bass Planar speaker - Part 3 tune and measurements 

Wonderful realism Joppe. I just love it.

Wow, what a tune! I got taken back for a minute there.

Phenomenal!

That sounds awesome

Tell me if you have already thought of this, but I've just thought of a way to find tune the tension very easily. First, design the frame with a front and back as you have done here. The idea is to stretch the film between the frames, like a sandwich. The frames are simply rectangles, with rectangular holes, the same as what you've done here, but make one have a smaller hole then the other. Maybe by 10mm or so. So when they are together, there is a 10mm lip because the one with the smaller hole will overlap. To the one with the lip, apply a 20mm wide weather strip made of closed cell foam to the lip. tension the film onto one of the frame with the larger hole. The one without the foam, ensuring no wrinkles, and even tension and secure it. As you clamp the second frame onto this frame, the foam will press into the film. This will add tension. The more clamp pressure, the more tension. They can be clamped with screws or bolts. This could be used to create both uniform or non uniform tension. Because the weather strip is also being sandwiched sure to it being 10mm wider then the lip, as tension is applied, the down is compressed. This keeps the two frames apart and prevented vibration. Magnets would be attached to the lip frame. I this way, the gap distance between the film and the members would be roughly the same, regardless of compression. The first will of course compress the foam a little, but hopefully not much. So yeah, push only arrangement. Or perhaps, if magnets where in push pull, the foam would compress from the film at half the rate of the movement between frames,meaning the film would remain centered? The foam may also absorb excessive energy, leading to better dampening, which may be good for lower frequencies. Just an idea

Those low distortion measurement values are very impressive!

Happy Birthday to Puss 😼😼

Open my world

very nice, huge gain in output! is it possible to have too much magnet strength that it will detract from low bass output? (qms?) i recall that smaller magnets on traditional woofers was actually better for acoustic suspension bass design.

Qes is so high... I guess that makes sense. It is a lot of magnetic flux over a large area.

Why not build the frame with hollow steel tube? Or aluminium? My original Magnepan Typani back in the early 70s had steel tube frames.

Мне нравится! Классно!

Much more adept than the dual foil version. What are the dimensions of the bass planar?

I am amazed how close the two measurements are. Foil tension seems to be under control!

so.. next would be cylindrical same pole opposing magnets in checkered pattern and hyperelipse shaped coils in the foils?

it looks pretty good between 40-80hz drops off above that... lol maybe a lo-mid driver coming soon?

What is dimension of magnets?

Brown : 20 hz , 79 db : 30 hz , 88 db. Blue : 20 hz , 88 db : 30 hz , 98 db . Looks good .

MiniDSP crossover is cheap and good!