[Timo]

Originally Posted by Timo

The Filter Balance knob (all filter modes) controls the input and outputs of each filter. Turned fully anti-clockwise the signal (oscillators) will be routed just through Filter 1 (as if Filter 2 is bypassed). Turned fully clockwise the signal will be routed to just Filter 2 (as if Filter 1 is bypassed). In the middle, it runs the signal through both Filter 1 and 2 together as per the given configuration shown in the routing diagram for any particular routing mode.

The above can be a bit complex to get your head around as Filter Balance's mixing control is actually multi-faceted (three pronged) - in that, depending on any selected value for Filter Balance, the routing is changed further still. I'm going to redo the above picture to take filter balance into account, as the explanation in the (Virus B) manual is poor (not sure what the TI manual is like) and I feel it's a key element to grasp properly if you want to fully understand how the filter routing works.

Eventually redid the diagram for a slightly truer representation showing the complexity of the classic Virus filter routings when taking Filter Balance into account:



Was interesting to hear and find that in Serial mode there actually appear to be three wholly separate channels of filtered audio that are being processed and mixed:- Filter 1, Filter 1+2 in series, and Filter 2. These three channels appear to be merely cross-faded between each other using the filter balance knob (-64, 0, and +63 respectively). It seems that Filter 2 may actually have to be instantiated twice behind the scenes to do this, whereas Filter 1 can be tapped off as it comes first in the chain.

In Parallel mode, the Filter Balance appears to work as a straight forward summing blend of Filters 1 and 2.

In Split mode, the Filter Balance is nothing more than just a volume balance control for each channel. It's also the only filter type that is stereophonic (well, more like dual mono, each panned hard left and right).