Global
The first slider, labeled OSC Level, controls the global level of all five voices. When pushed beyond its midpoint, the OSC Level slider introduces slight harmonic distortion by gently overdriving the signal.
The Sub section controls Katla’s five sub-oscillators. You can adjust their level, set their octave position, and choose between sine or square waveforms. Each sub-oscillator is linked to its corresponding voice and is influenced by that voice’s level and octave settings.
Noise/EXT
Section titled “Noise/EXT”Control the amount of pink noise using this slider. When the EXT button is pressed, noise is disabled and the slider controls the external input level instead.
The noise and external input is routed through a tilt EQ. Depending on the COLOR slider, the EQ will boost high frequencies above a central pivot point (800 Hz) and cut frequencies below, or vice versa. This brightens or darkens a signal with a single control, efficiently shaping the overall tonal balance.
Glide (portamento) creates a smooth transition in pitch between two notes. The amount slider sets the time it takes to reach the new pitch.
The glide time automatically scales with the size of the interval: large jumps take longer, while small movements glide more quickly. For example, a two-octave leap takes noticeably more time than a half-step slide. This produces a natural-feeling portamento where big intervals have room to “travel,” and small pitch adjustments remain fast and responsive.
Descending pitches glide slightly slower than ascending ones (about 10% longer), adding an organic quality.