Controllers We have developed a number of premium audio components to complement our range of amplifiers. This includes products such as mixers and controllers for signal processing, which are crucial for applications such as multi-zone public address systems. Digitale system controllers and modular mixers for signal processing. Our ML 203 multi-band limiter is a sophisticated volume limiting solution. Thanks to its multi-channel, aurally compensated limiter, this device delivers almost inaudible signal limiting even with excessive input levels. Multi-zone system in listed historical buildings. The modular mixer system MX 6 with extended modules was designed for multi-zone sonication for example in gastronomy.