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318 Chapter 23 Ultrabeat
The bandpass (BP) filter only allows a certain frequency range (a frequency band)
centered around the Cutoff frequency to pass. It can be used in the upper, as well as at
the lower, end of the frequency spectrum to reduce the highs and lows of a sound.
The Cut knob determines the Cutoff frequency, and defines the point in the frequency
spectrum where reduction begins. Depending on the type of filter you select, you can
make a sound darker (LP), thinner (HP) or more nasal (BP) by adjusting the Cut value.
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.
Dirt is a parameter developed especially for the noise generator. Turning up the Dirt
knob roughens up the pure, white noise appreciably, making it more grainy.
Note: The Dirt parameter is especially effective at high Resonance values.
Between the noise generator and the filter section you’ll find a signal flow switch that
controls the routing (Filter Bypass button). Repeated mouse clicks will send the signal
to the filter (Filter Bypass button turns red), or bypass the filter and send it directly to
the EQ section (Filter Bypass Switch remains gray). The direction of the arrow on the
Filter Bypass button illustrates the routing.
Note: The Filter Bypass button determines the signal flow. It doesn’t turn the noise
generator on or off. Use the On/Off button for this (see above).
In the noise generator, the Filter Bypass button operates as per the oscillators and ring
modulator: it determines whether the signal is sent to Ultrabeat’s main filter or
bypasses it. It has no effect on the independent filter contained in the noise generator.
This is deactivated with the Byp button in the noise generator filter section.
It is therefore possible to filter the noise generator signal twice. In many instances, you
may want the noise generator signal to bypass the main filter, freeing the main filter for
other duties—an important element when programming drum sounds.