DISTORTION

Motor Systems

To greatly reduce driver distortion, THIEL uses several design techniques to improve driver excursion, stabilize the strength of the motor system's magnetic field, and make the field more symmetrical. As the driver's voice coil moves forward and backward in the magnetic gap, the magnetic field acting on the coil changes in intensity, producing distortion. To reduce distortion in most drivers, THIEL uses an unusual short coil/long gap voice coil design which causes the intensity of the magnetic field acting on the coil to be constant during movement. Other THIEL driver motor systems reduce distortion by utilizing a specially shaped pole to achieve a symmetrical magnetic field around the coil.

A copper sleeve surrounding the center pole is used in all woofers and in most of the midrange drivers to cancel unwanted changes in magnetic field strength caused by the amplifier's current through the voice coil. The result is a more stable magnetic field and reduced distortion.

Also, short coil/long gap design, special pole geometry, and copper rings all reduce problems caused by varying coil inductance and therefore improve the stability of the frequency response.

Conventional long coil/short gap woofer

CS7.2 short coil/long gap woofer

Distortion measurements

Standard long coil/short gap system

CS7.2 woofer with short coil/long gap motor system

Crossover Components

Most speakers use electrolytic capacitors in their crossovers. Although inexpensive, electrolytics cause audible distortions. THIEL's crossovers primarily use combinations of polypropylene and custom-made polystyrene capacitors for very low distortion and transparent reproduction.

Air core inductors wound with high purity, low oxygen copper are used to further reduce distortion. In addition, the speaker's internal wiring uses custom- made, solid conductor, high purity copper wire with Teflon insulation. All connections are made with silver solder.

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