What is a magnetostatic loudspeaker?
A magnetostatic loudspeaker, in its essence, is a dipole loudspeaker which can be similar to the electrostatic loudspeaker. Unlike electrostatic loudspeaker, which uses high voltages, magnetostatic loudspeaker uses high currents. The construction of the magnetostatic loudspeaker consists of permanent magnets which provide static magnetic field and wires or strips carrying audio frequency currents. They are bonded to a thin diaphragm. Moving forward, the current flowing in the conductors interacts with the magnetic field and creates sound in much the same way as in a conventional dynamic driver. Because of its dipole structure, this kind of speaker creates sound mostly to its front and back.
Good sound quality
The impedance of a magnetostatic speaker is often mainly resistive. However, in some cases, it may be so low that the amplifiers have to be ready to accommodate the low impedance load. Magnetostatic speakers provide good sound quality and may be very thin, but for producing lower frequencies with good enough sensitivity, their height and width dimensions must be rather large.
Magnetostatics largely work like electrostatics in that they also employ a large moving membrane. Also, the membrane is driven over its entire surface. But the similarity ends there. Magnetostatics, as the name implies, derive their driving power from permanent bar magnets. The membrane can have a conductive layer, like with electrostatics but most of the time it consists of the same base material (Mylar) with conductive strips or wires bonded to the mylar. Behind the membrane are strips of bar magnets to cater to the driving power. The thin conductive strips are used for mids and sometimes highs, while the thicker copper or aluminum wires are used for the bass.
Magnepan calls the method of bonding the conductive strips to the mylar – “semi-ribbon”. A true ribbon consists of a long aluminum strip that is both tweeter and conductor at the same time. The ribbon tweeter, due to its length, doesn’t need an impedance-matching transformer to reach a reasonable impedance. It has bar magnets only on the sides, leaving the tweeter capable of breathing freely to the front and rear, creating what some people consider to be the purest and possible the finest tweeter in the world.
Contrary to full-range electrostatics, full range magnetostatics can have an excellent, and very satisfying bass response. The bass output will be sufficient even for heavy music, although they may not “rock” as regular dynamic speakers do. This is due to the lack of coloration and boxiness. Jim Winey invented and subsequently popularised the planar magnetic speaker in 1969. His designs became very popular because they were and still are relatively affordable. They offer incredible value for money. But the brand’s top products also rank very highly among audiophiles and reviewers alike.