Fancyyyyy Synthesis K-Accumulator Eurorack Complex Oscillator Module

We say...

We must admit, we're pretty excited about this one. Fancyyyyy Synthesis's follow-up to the unique and brilliant Rung Divisions goes way beyond anything we were expecting. Quite possibly the most technically advanced oscillator on the market, the K-Accumulator is sure to keep adventurous synthesists busy for quite some time. Big tip!

Manufacturer's description

K-ACCUMULATOR is a complex oscillator that folds advanced phase modulation and wave-shaping synthesis in ways never explored in hardware before.

Its architecture combines a Carrier/Modulator core with a smoothly morphing 3D waveshaping matrix and harmonic-shaping techniques derived from complex sine–cosine synthesis, a Universal Function Generator, and a Delta-Sigma pattern generator; all cross-normalized into a deep self-modulating topology that responds to itself.

It can be a complete voice with free or quantised Just-Intonation or Equal-Tempered sequencing and variable envelope shapes, or it can be a hyper-flexible organism capable of fluid mutations between rhythm, melody, tone, texture, drone and chaos; with harmonic and subharmonic locking, pulsar-driven bursts and vowel-like formants, broken symmetries and edge-of-chaos feedback at multiple architectural scales.

We designed every part of K-ACCUMULATOR to operate across the full range of time-scales, from sub-audio modulation to pitch and timbre, many of them shifting character as they cross into the audio domain.

No menus, no shift functions, no hidden modes; just immediate tactile control that feels alive under your fingertips. Or crack it open with precise control through 23 audio and control patch points into its manifold.

It’s a 20th-century form updated for 21st-century synthesis, designed for performability.

Complex Oscillator with Complex Outputs

​The Main oscillator features Sine / Cosine outputs at all matrix positions. These can be used as a complex stereo output pair. All waveshaping techniques modulate the perceived relative phase position of these waveforms, creating stereo animation.

Novel Synthesis Techniques

​Harmonic wavefolding folds the core sine and cosine with a monotonic distribution of harmonic energy. Blended harmonic frequency shifting smoothly morphs the fundamental to the nearest integer harmonic. Damped cross phase modulation drives the system to chaos. Asymmetric phase modulation removes half of the phase modulation sidebands, similar to granular pulse trains. Formant synthesis narrows the window and generates overtones. Sync damping progressively synchronises the oscillator to the function generator. Damped Self feedback interacts with folding and blending in unique and surprising ways. Harmonic stretching frequency shifts all the generated harmonics whilst keeping the fundamental unaltered, allowing you to detune the harmonics within a sound. The hyper-flexible function generator can be driven at audio rates for pulsar synthesis, independent to the main oscillators morphing wavehsaping matrix.

Manifold structure

K-ACCUMULATOR smoothly morphs between super-positions of an eight node matrix, progressively remapping the panel controls to waveshaping destinations for the Carrier / Modulator Oscillator section. At any matrix position, these algorithms can be progressively sync’d and amplitude modulated by the Function generator, enabling a smooth transition in and out of pulsar synthesis / windowed sync / formant synthesis using our new Sync Damping algorithm.

External pitch tracking and time domain waveform replacement resynthesis

In addition to all the internal modulation methods, K-ACCUMULATOR features an external input, which can be used for external pitch tracking (at audio-rate) or as an input to the damped sync section. The external pitch tracking can be used in conjunction with quantisation to harmonise with external sources, or with non-pitched sources it can be used an interesting noise / texture generator.

Root frequency architecture and quantisation

​The root frequency can be selectively sent to the OSC, UFG or both. A Just Intone or Equal Tempered scale can be chosen to quantise to. The Modulation oscillator can track the frequency of the OSC, or the UFG, in blended harmonics or ratio modes, or be free-running.

Connects to Rung Divisions

​K-ACCUMULATOR connects to Rung Divisions via a pin header on the back of the module, it will drive Rungs with Clock and Data signals from the UFG and Mod oscillator.