The Radikal Technologies Spectralis combines synthesis, sampling, sequencing, and a filter bank in a synthesizer workstation module.
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This online-exclusive bonus material supplements Electronic Musician's review of the Radikal Technologies Spectralis in the July 2007 issue of EM.

Put It in the Bank

Other than modular synthesizers, the Spectralis is the only synth I''ve seen that has a built-in filter bank. The bank provides a lowpass filter, a highpass filter, and eight bandpass filters with fixed frequencies ranging from 265 Hz to 3.9 kHz.

In the front panel''s Filterbank section, pressing the Level button assigns the first ten numbered knobs to control levels for the ten filters. The next five knobs control the filter bank''s overall level and the levels routed to the synth filters and effects section. Pressing the Pan button lets you use the first ten knobs to adjust each filter''s stereo positioning, but only if the filter bank is routed directly to the Sum outputs. The display reflects the precise values as you turn the knobs.

Being able to adjust each band''s level is useful for sculpting sounds—especially external audio streaming through the filters in real time—and for duplicating the resonances of acoustic sound sources. Because you can program the Step Sequencer to modulate filter bank parameters, the Spectralis can dynamically shift the spectra of your timbral material. You can generate some pretty nifty rhythmic patterns just by sequencing filter parameters and processing noise.

Manual Labor

The Spectralis is a very ambitious project, and its price-to-performance ratio makes it a good value that should get even better with further development—assuming you have the patience to scale its learning curve. The convoluted operating system is virtually incomprehensible unless you read the manual, though the onboard help files can often point you in the right direction. Nonetheless, it''s still difficult and sometimes impossible to find the information you need.

If you''re determined to become one with the machine, you''ll need to slog through the entire manual, and even that won''t get you all the way there. It''s often hard to grasp what the manual''s author is trying to say; some serious reorganization and copyediting by a native English speaker would help immensely. The onboard help files offer some insight into certain controls and their functions, but scrolling though a 2-line LCD is undeniably laborious.