This is where the unwanted frequencies in the sound are removed. The filter on the BassStation is the most popular type, a Low-Pass Filter, which removes the higher harmonics first and, as it is closed down, removes the lower harmonics until only the fundamental or nothing is left. This is the type supplied on all synthesisers and the most musically useful, especially for bass.
This switch allows you to change how drastically the frequencies above the cut-off point are removed from the sound. In the 12dB position, the cut-off slope is less steep so the higher frequencies are not attenuated (reduced in volume) as much as they are in the 24dB position. This makes the resulting filtering in the 12dB position more subtle than the 24dB, which you should select if you want the cut-off to be more obvious.
This knob controls the basic cut-off frequency of the filter. All the way to the right, the filter is wide open allowing all the frequencies produced by the Oscillators to sound. As you turn the knob to the left it closes the filter, cutting out harmonics, starting with the highest but increasingly lower ones until only the fundamental or nothing at all is allowed to sound (at the far left). If ever the BassStation is making no sound at all and the Volume knob is turned up, the most likely cause is that the Filter is fully closed. Turn the Frequency knob to the right to let the sound out.
This knob allows you to boost or emphasise the frequencies around the Cut-off frequency (set by Frequency knob above). For this reason on some synths this control is known as Emphasis. At the far left there is no boosting of the cut-off frequency, but as you turn to the right this frequency will be boosted until at the far left it goes in to oscillation producing a new pitched element (similar to feedback on an electric guitar). If ever the BassStation produces a high whistling sound, the chances are this knob is too far to the right. Unless you want this self-oscillating effect, keep the resonance control away from the extreme right setting. Increasing the Resonance is very good for bringing out modulation (movement or change) in the filter cut-off frequency, such as in Acid basslines and other very up-front sounds. Keep the resonance to a minimum if you want more subtle less striking sounds.
This knob determines the amount of Filter Tracking going into each voice. It can be adjusted to the desired discrete filter tracking value from 0% to 100%. When set to “100%”, it causes the filter in each voice to “track” the keyboard.
This control determines the amount of Envelope 2 that modulates the filter. This control is bipolar, with 0% at the centre position, +100% when turned fully clockwise, and -100% when turned fully counterclockwise.
This control determines the amount of LFO that modulates the filter. This control is bipolar, with 0% at the centre position, +100% when turned fully clockwise, and -100% when turned fully counterclockwise.