The diode array is a mix of silicon and germanium diodes to achieve the desired clipping characteristic. When the audio signal is clipped, a limiter will generate harmonic and intermodulation distortion above and below the frequency of clipping. The output of each clipping stage is then filtered for distortion outside the band before all bands are recombined into a single waveform. In practice, multiband limiters are difficult to implement. Because the various filters of different orders will phase-shift the signals in each band, the overall response of a multiband limiter may not be flat and can sound unnatural.
Several techniques can improve the performance of multiband limiters.
First, the bands can be chosen according to psychoacoustic masking curves that help conceal distortion. Second, compressors can be introduced before the clipping stage to control the degree of clipping. Distortion detectors can control the amount of compression. Third, all-pass filters can be sprinkled about to collimate the phase responses of the bands. On average, the bass frequencies in an audio signal usually have the highest amplitudes.