Frap Tools Fumana Eurorack 16 Band Spectral Filter Module

The FUMANA is an all-analog dual filter bank with various control to access dynamically these bands. Each filter bank is composed of an array of 16 independent 48dB/oct bandpass filters. Having two identical filter arrays, allows you to use one of those for spectral analysis (of a modulator signal) and the other for spectral re-synthesis (of the main signal). Each array is sub-grouped in odd and even bands (numbering these increasingly from 1 to 16 from left to right). It is possible to apply different signals to odd and even bands, both for main and/or modulator arrays. This, together with the 16 envelope followers connected to each band of the modulator filterbank, and the 16 VCA connected to each band of the main filterbank, allows the FUMANA to perform a single 16 bands or a dual 8 bands analog spectral transfer.

While the upper section provides access to each main filter’s direct output, the lower section has 4 voltage controllable parameters to manage two independent functions for further spectral editing: tilt and parametric scan.

The tilt control, as the name suggests, tilts the spectrum, adding and subtracting amplitude to the 16 bands, emphasizing lower or high bands, and attenuating high or lower bands: this is managed only with the green potentiometer.

The parametric scan, instead, works with three parameters: peak/notch, band selector and width. Like in a parametric equalizer, where is possible to set peak/notch gain, frequency, and slope, the FUMANA uses three parameters to set which is the center band to perform this manipulation, then if that band should be emphasized or attenuated, and how this action is extended to nearby bands.

In addition to the 16 bandpass outputs, there are other 4 outputs provided: the all bands output, the all envelope followers output, the odd and even bands’ output. These two have the options to be inverted in phase with two switches, in order to obtain even more combination when summed together, maybe/also with the “all bands output”, using, for example, the 333 module.

Since a spectral transfer tool may be used as a “vocoder-like-effect”, the FUMANA provides an input for an external noise which may be used for unvoiced (fricative/sibilants) sounds as words containing or starting with s, f, z, ch and other fricative sounds ([s] [z] [?] [t?] [d?] [ts] [?] [f] [v] [?] [θ] [?] etc).

Key Features

• TWO 16 bands filterbanks: main filterbank of 16 fixed bandpass filter 48 dB/oct, secondary for analysis and creation of envelopes to be used as modulation signals.
• parametric scanning: gain or peak/notch, center, width
• true 16 bands analog spectral transfer, also usable for vocoder alike results
• odd & even input/output, to split the filterbank in two for multiple or hybrid processing
• flat frequency response, which provides a wider sonic palette
• unvoiced section
• first module capable a full 16 bands, or two 8 bands, spectral transfer
• analog design