Native Instruments Reaktor 6 is a versatile modular software music studio and digital synthesizer platform [31]. It serves as a comprehensive DSP (Digital Signal Processing) environment for instrument design, allowing you to build everything from custom synthesizers and samplers to advanced effects and sound design tools [11].
These tutorials provide a practical look into building instruments and working with the modular system in Reaktor 6: Making Music With Reaktor 6 Pt.1 - An Introduction to Racks YouTube · One Man And His Songs native-instruments-reaktor-6-4-3-full-version