A speaker has a magnet structure mounted ahead of the speaker diaphragm to
produce a shallow compact unit. The magnet structure defines a flux gap,
and a voice coil residing in the flux gap is connected to a main
diaphragm such that drive current applied to the voice coil moves the
diaphragm to generate sound. The voice coil and magnet structure provide
a flux gap at the rear of the magnet structure, ahead of and centered on
the main diaphragm, while the magnet occupies space within the cone,
freeing up space in the rear. In one embodiment, the magnet structure has
an additional flux gap located at its forward end and the speaker
includes an additional diaphragm driven by a coil positioned in the
additional flux gap. The main diaphragm and additional diaphragm are
better positioned to maintain a common sound center for enhanced spatial
fidelity and different tuning techniques present a broad flat response
below crossover to form a pinpoint sound source of wide angular coverage.
The back wave couples directly into an enclosure, which may be a shallow,
panel mount assembly. The magnet structure may possess an opening
extending through the center of the structure allowing control over the
acoustics through enclosure compliance or damping effects to enhance
response of the system.