Finlay Shakespeare on Filters Typology.
Voltage controlled filters are an important facet of synthesizer design, and therefore electronic music in general. The topologies used to allow a filter's cut-off frequency to be controlled by an external voltage will alter how a core filter topology will sound. Distortions and other non-linearities are usually added into the filter's audio path in making the cut-off frequency voltage controllable. A selection of discrete voltage control topologies are chosen, discussed and finally examined via the Audio Precision 2700 audio test system. Comparisons are then made between filters, highlighting which voltage control element possesses certain musical and acoustic properties.