Tunefish 4 is a compact synthesizer designed as a streamlined successor to its predecessor, delivering powerful sound creation capabilities with a fresh approach. Developed initially for the 64k intro "Turtles all the way down" by the Brain Control demoscene group, this instrument features unique synthesis algorithms that set it apart from earlier versions. It is available in both VST and AU formats, making it accessible for a wide range of digital audio workstations.

The user interface of Tunefish 4 has been significantly enhanced to provide clear visualization of all modulation sources and destinations, simplifying sound design. It employs an additive synthesis-based wavetable generator, complemented by a noise generator capable of producing noise across any frequency and bandwidth. The filter section includes lowpass, highpass, bandpass, and an advanced notch filter, offering a broad palette of tonal shaping options.

Tunefish 4 includes two ADSR envelopes and two LFOs that can be flexibly routed to numerous parameters through a modulation matrix, allowing intricate modulation possibilities. Its effects section supports flanger, chorus, distortion, delay, reverb, EQ, and formant, with the ability to stack up to ten effects in any order, enabling extensive sound processing and customization. This combination makes Tunefish 4 a highly capable and expressive synthesizer for creative music production.