Magma basses employ the 'LightWave' optical pickup system. LightWave pickups exhibit an extraordinarily even frequency response throughout the whole tonal spectrum. An infrared-emitting diode on one side of the string illuminates the string as it moves. The shadow of the moving string passes over an optical sensor on the other side of the saddle. The signal generated by this sensor is converted into an audio signal and then routed through the preamp to your amp. The non-magnetic nature of the pickup results in truer harmonics, lower distortion, greater overtones and enhanced sustain. Lightwave pickups can sense down to 4HZ, so an amp capable of reproducing very low frequencies is recommended to make use of these capabilities.