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320 Chapter 23 Ultrabeat
The abbreviation BR stands for Band Rejection filter. In this mode, the area (the
frequency “band”, to be more exact) around the Cutoff frequency is filtered out while
frequencies that lie further away (from the Cutoff frequency) are allowed to pass. The
mid frequencies become softer and the low and high frequencies remain unchanged.
Below the filter type buttons, you’ll find two buttons labeled 12 and 24. These allow you
the select the slope of a filter. All of Ultrabeat’s filter types offer a filter slope of either 12
or 24 dB/octave.
Note: Filters don’t completely remove the parts of the signal that you wish to filter out
and always work with limited precision in the selected “band”. The steepness or slope is
measured in decibels of damping per octave (dB/oct). Frequencies that are located
close to the Cutoff frequency are generally reduced less than those that are farther
away. The higher the slope value, the more apparent the level difference is between
frequencies that are nearer the Cutoff frequency and those that are further away from
it.
The Cut knob determines the Cutoff frequency of the filter.
Note: Adjusting the Cutoff frequency can make a sound darker (LP), thinner (HP), more
nasal (BP) or more transparent (BR), dependent on the type of filter chosen.
Cutoff can be modulated by the sources found in the Mod and Via menus. If a Mod
source is activated, the effect it has on Cutoff is set by the (Mod) ring that surrounds the
knob. If a Via source is activated, its effect can be set by moving the slider that appears
on the Mod ring. Colored areas between the Cutoff knob and its surrounding ring
clearly show the values of the Mod modulation (blue) and the Via modulation (green),
compared with the mean value (red).
If neither a Mod or Via source is selected (set to Off), the ring and slider remain hidden.
Increasing Resonance boosts frequencies that surround the Cutoff frequency. Values
range from 0 (no increase) to self-oscillation of the filter at high Resonance values.
Note: Self-oscillation is typical of analog filter circuits. It occurs when the filter feeds
back into itself and begins to oscillate at its natural frequency, when high resonance
values are used.
If a Mod source is activated, the effect it has on Resonance is set by the (Mod) ring that
surrounds the knob. If a Via source is activated, its effect can be set by moving the
slider that appears on the Mod ring. Colored areas between the Resonance knob and
its surrounding ring clearly show the values of the Mod modulation (blue) and the Via
modulation (green), compared with the mean value (red).
If neither a Mod or Via source is selected (set to Off), the ring and slider remain hidden.