MartinLogan Monolith III user manual An Electromagnetic Transducer

major contributor to the sonic purity of	possible. When you look at the prob-	cone or dome is just "along for the ride".
the electrostatic concept due to its	lems of traditional electromagnetic	The basic concept of these drivers
exceptional linearity and low distortion.	drivers, you can easily see why this is	require that the cone or dome be
Since the diaphragm of an electrostatic	so beneficial .	perfectly rigid, damped and close to
		massless. Unfortunately these condi-
speaker is uniformly driven over its	The cones and domes which are used	tions are not available in our world
entire area, it can be extremely light and	in traditional electromagnetic drivers	today.
flexible. This allows it to be very	cannot be driven uniformly because of
responsive to transients, thus perfectly	their design. Cones are driven only at	To make these cones and domes
tracing the music signal. As a result ,	the apex. Domes are driven at their	move, all electromagnetic drivers must
great delicacy, nuance and clarity is	perimeter. As a result, the rest of the	use voice coils wound on formers,
			spider assemblies, and
			surrounds to keep the cone or
			dome in position (see Figure
An Electromagnetic Transducer			9.). These pieces, when
			combined with the high mass of
			the cone or dome materials
			used, make it an extremely
Surround Cone	Dust Cap		complex unit with many weak-
			nesses and potential for failure.
	Voice Coil Former
			These faults contribute to the
			high distortion products found in
			this type of driver and is a
			tremendous disadvantage
	Spider (Suspension)		when you are trying to change
			motion as quickly and as
			accurately as a loudspeaker
			must (40,000 times per
			second!).
Basket Assembly	Magnet Assembly
Magnet
Voice Coil	Magnetic Gap

Figure 9. Cut away view of a typical moving coil driver.

Notice the complexity due to the high number of parts.

Monolith III User's Manual Page25