The answer has been given, but it was deliberately removed.

[Magluvin]

Its a shame. The speaker thing got me interested. But, the speakers magnet with the top plate and the bottom pole piece, the field in the gap is  N to S crossing the coil perpendicular. In the 3 coil example it would seem it is not the same. But is there something to it none the less? If I had to guess the 2econd coil might be the collector coil. Not all up on the TPU to understand otherwise yet as to what I should be seeing. But it looks interesting to try, Maybe input to coil 1 and 3 and 2 is the output. Would we see some strange effect? Its not a typical winding if 2 is the collector, pickup coil, whichever. But then we have the term control coil. So Im at a loss,

Mags

[sm0ky2]

If we assume he had an inkling as to the true magnetic portion of the field
We also have to assume that by his speaker analogy
He meant in the cross-sectional vector
Not up and down like an actual speaker.

[sm0ky2]

A pancake coil acts more like a solenoid or linear inductor
It generates a linear-oriented magnetic field.
A distinct north and south magnetic pole can be found
Above and below the coil. So a south facing magnet placed under it
Causes a repulsion during the first half of the wave
And an attraction during the second.
And by this manner, converts electricity into physical vibration
Producing sound, amplified by the paper cone.


In a toroid, or a coiled toroid: the field is both radial
And circumferential.


Circumferential internally, and through the core.
radially externally, around the wire, following the signal.
It is this second part that causes repulsion and attraction
Between the 3 coils.
This results in a horizontal physical vibration.
Which also produces sound. (audible or supersonic)
We could turn this into a speaker, place this on a box
Of approx 1/4 wavelength
Or 1/4 of a lower octave wavelength
With one open end, to act as an amplifier
Like how they amplify a tuning fork.


That being said:
There is a vertical fluctuation of the magnetic field in SM's device.


This is a result of repulsion between the turns of the parallel coil.
It is very tiny, but present.
They expand and contract, slightly out of phase
with the signal.
I suppose in some theoretical world we possess an electronics
adhesive (short of high-temp cured ceramic) that can hold them.
This would eliminate the losses associated with the effect.
But since the source is renewable, it's trivial.


The audible tone and physically perceptible vibration are
entirely caused by the horizontal vibrations. Not the
'transmission line' expansion of the parallel coil.

[Magluvin]

Ok. Just winging it, here is the 3 coils layered with cork as Turbo suggested. 70 turns each of Radioshack green rolls of magnet wire I had laying around. I believe it is 26awg.

Didnt know how far a roll will go, and figuring in the additional length as each layer diameter increases, I stopped at 70 turns where a full roll came close to 90 on the first wind. So made the adjustment then.

Will put terminals on tomorrow. As the inner winding is sandwiched in cork, I put an outer layer of cork after the 3rd winding.

Mags

[Magluvin]

So far it works as a 2/1 transformer using the 2 outer layers in series and the middle coil as an open output. Will see if things change if I load the middle coil.

Mags