Filters

The two multimode filters are among the most important components in FabFilter Twin. Especially when using modulation, they are the key to creating great sounds. We have carefully tuned the filters to avoid the whistles and other digital artefacts that are common with other digital filters when you change the cut-off frequency at maximum resonance. Our filters sound crazy but never over the top!

You control each filter with the following settings:

• Freq/Pan
  The inner Freq knob sets the cut-off frequency for the filter. The outer ring sets the frequency offset for the left and right channels separately, which enables you to create stereo effects without phase problems. Moving the pan ring to the left will lower the cut-off frequency for the left channel while increase the cut-off frequency for the right channel, for example. Both are modulation targets.
• Peak
  

  The Peak knob adjusts the filter resonance. A little resonance will cause the filter to create warmer and more characteristic tones. Around position 8, the filter starts to self-oscillate at the cut-off frequency which creates terrific effects in combination with the sound from the oscillator. At these high peak values, the filter produces deep, ringing bass tones if you set the Frequency knob around position 3 or 4.

• Enabled
  The Enabled button toggles the filter on and off. The main reason to disable a filter is to reduce CPU usage.
• Characteristic
  The Characteristic button enables you to select one of the six unique filter characteristics. FabFilter One is the original filter characteristic taken from our award-winning FabFilter One synthesizer. It's perfect for general usage. The other characteristics range from the very smooth-sounding Gentle characteristic, to the extreme Raw filter with lots of overdrive. Try to experiment with these different characteristics while designing presets: they really give a unique character to your sound.
• Response
  The response of each filter can be set to either Low Pass, High Pass, or Band Pass. In Low Pass mode, the filter will pass through frequencies lower than the center frequency. In High Pass mode, frequencies higher than the center frequency will be passed through. In Band Pass mode, only the frequencies around the cut-off frequency will be passed through.
• Slope
  The slope switch sets the steepness of the filter, which controls how aggressively the frequencies around the center frequency are filtered. You can choose between 12 dB/octave and 24 dB/octave. For example, if the response is set to Low Pass, more high frequencies will remain at 12 dB/octave than at 24 dB/octave.
• Routing
  The filters can be routed in Serial, Parallel and Per Oscillator mode. When the Serial routing is used, the summed signal of the two oscillators will first be filtered by Filter 1, then by Filter 2. When Parallel is selected, the summed signal of the two oscillators will be fed to both filters, after which the results are summed. Using the Per Oscillator setting, the signal of Oscillator 1 is filtered by Filter 1 and the sound of Oscillator 2 is filtered by Filter 2. In this case, the signal from the noise oscillator is added to the inputs of both Filter 1 and Filter 2.

Interactive filter display

With the display button in the left-bottom corner of the filter section, you can toggle between the default knob view and the filter display view. This interactive filter display makes it easy to adjust the filter settings and also enables you to tweak them in parallel.

• Drag the button for filter 1 or 2 to adjust the frequency and the peak value for that filter.
• Drag the center button to adjust both filters in parallel. Holding down the Alt key while changing filter 1 or 2 will have the same effect.
• Hold down the Ctrl and Alt keys (Windows) or the Command and Alt keys (Mac) and drag the button for filter 1 or 2 to adjust both filters simultaneously, but in the opposite direction.
• Shift-click on the button for filter 1 or 2 to toggle the filter slope.
• Ctrl-click (Command-click on Mac) on the button of filter 1 or 2 to toggle between the different filter responses.

Tips

• When you want to change the frequency, peak or pan setting of both filters at the same time, just hold down the Alt key (Windows) or Option key (OS X) while turning a knob.
• In 24 dB/octave mode, the filter will use slightly more CPU power than in the default 12 db/octave mode.
• The settings of the filter section can be stored as a section preset.

Next: Output

See Also
Overview