planar technology, Monsoon vs. Magnepan

Yes. More control of the speaker diaphram. Push-pull vs single ended drive.

I believe the Monsoon speakers are based on the planar technology developed by Bruce Thigpen of Eminent Technology.

http://www.eminent-tech.com/history/eminenthistory.htm

Bruce is a madman. That fan sub is not of this world.

Eminent Technology, Inc. Planar Magnetic Loudspeakers and Audio Technology

The diaphragm isn't «controlled» in any way, just driven by the force induced by the interacting magnetic fields of permanent magnets and current in the conductor paths on the diaphragm. And it's not really «push-pull» or at least not more so in the case of the dual-magnet array: magnetic force is simply force, independent of the magnet location.


Yes and no. In theory the harmonic distortion is lower with a double magnet array. Because the strength of a magnetic field drops in intensity with the square of the distance. A membrane movement thus causes a fluctuation of the driving force. A double magnet array takes care for this issue. Now if the default distance of the diaphragm to the magnet is high enough and/thus its displacement relatively low, the magnetic field may vary to a tolerable or negligible degree.

A decisive disadvantage of the double magnet array is the front magnets in the way of sound radiation towards the listener. Apart from the fact that they represent bad aerodynamics – hence constrict membrane and air movement (which applies to the rear magnets as well) –, they force the sound waves to interact with them in the form of reflections, standing waves and irregular acoustic impedance. This can lead to transient corruption and colorations. If the system is only responsible for bass and lower midrange, it may be a lesser issue (note the concerned wavelengths!). Above it is of relevance, though. So from this perspective renouncing the front magnet system has its merits.
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I vaguely remember an old ET advert on Stereophile/AS that explained that one of the advantages of double magnet arrays is more control over the membrane and remember the term push-pull being used. But it was a long time ago...

Not necessarily. There's a lot more to a planar than how the magnets are laid out. Push-pull will increase the efficiency, however, having magnets on both sides would require some careful planning of the layout to ensure that the panel is fully driven while not blocking sound radiation.

Also, the Maggie 3.6 and 20.1 use a ribbon tweeter, which is a slightly different technology than planar. Typically, magnets are put to the left and right of a ribbon, as opposed to the front and back of a planar. IIRC, you can build a magnetically single-ended ribbon, but almost everyone builds them with magnets on the sides so you can get dipole radiation. And believe me, you want dipole radiation off the ribbon.

Aren't the Monsoons computer speakers only? I don't think I've seen them as bookshelves or floorstanders.

It seems that Monsoon did have a short lived full sized speaker.

Product Review - Monsoon Audio - FPF-1000 Planar Focus Technology (PFT™) Speaker System

Monsoon, now Eminent tech, makes some very, very good speakers and the greatest sub woofer ever made. The only real sub actually.

115db at ONE hz? Yes.

Albert Von Schweikert had a hand is designing the Monsoon's.

I still use the Monsoons on my work computer. For a computer setup, they sound pretty good still.

....and now all one needs is to invent a musical instrument that will have output that low.