Published on May 13, 2013 pjoris2·29 videos
"The second in the series of videos showing the capabilities of the Serge Creature. This time looking at the Variable Q Voltage-Controlled Filter (VCFQ). The sounds made are mostly using the TGO saw output through the filter. Modulation from the TGO and SSG modules. Overview of the video:
Basic Filtering
(00:30) Filtering of a saw wave with the filter: lowpass output. Setting the Q of the filter higher with every sweep.
(02:00) The same, using the highpass output.
(02:30) Bandpass output
(03:00) Notch output. Does not seem to do much ...
The first section was using the "AGC In" input. This input has automatic gain control to avoid overloading the filter when setting higher Q-values. The input labeled "In" does not have this, but has a manual gain pot. You can overload the filter using this input.
(03:30) Not dramatically different, but you hear some saturation and see some distortion (squaring of waveform) on the oscilloscope.
Filter Cut-off Modulation
(04:00) Using the VC F (variable CV) input. There is also a 1/V Oct input, which I fail to demonstrate here.
(04:30) Some nice "vocal" sounds using audio-rate modulation.
Pinging the Filter: when feeding a pulse in the trigger in the filter resonates in an acoustic sound way: "pinging" the filter.
(05:00) Just some various sounds varying the cut-off frequency and Q settings.
(06:00) Using the CV inputs for Q and cutoff frequency.
(06:30) Feeding audio in the trigger input.
(07:00) And some audio rate modulation of Q and/or cut-off frequency. Getting into noise territory again !
The filter doesn't go into self-oscillation by itself, but it does when you feed the bandpass output back in the filter through the "In" input. Bringing up the gain then gives (without any audio output) self-oscillation of the filter. Note: you must use the bandpass out and the "In" input. Using the low-pass out or "AGC input" does not work.
(08:00) Demonstration of the self-oscillation. Hard to get a pure sine out of it. You can control overloading the filter with the gain, but if you turn it to far down you lose self-oscillation in higher frequencies.
Some sounds: two audio demonstrations (no relation between video and sounds any more ...)
(10:00) Random sequence using the low pass out
(11:00) Some pinging through an analogue delay pedal."