The analog stereo filter Ikarie is the result of a collaboration between Bastl Instruments and Casperelectronics. The module is a 12 dB state variable filter that can smoothly fade from lowpass to highpass. The inputs and outputs allow full signal processing in the stereo field. Optionally for control and modulation in the panorama, the circuit can act as a dual-peak filter. If only the mono output is used, the module behaves like a filter with two resonance values, producing sounds with formant character. The Beyond output outputs the spectral difference of both filters, effectively turning the circuit into a twin-peak filter. The audio input can amplify the input signal up to five times, which should be enough for harder sounds. The outputs, whether used stereo or mono, can also be modulated by the VCA; Ikarie recommends this as a backend module at the end of a stereo signal path. The internal envelope follower modulates the filter in one of three velocity levels; in addition, the determined voltage is made available to other modules via a CV output. The sound of the Bastl Instruments Ikarie can be described as rich and balanced, the well-balanced voltage controllable resonance also contributes to this.