VM2500 Blank Panel Module 1001 VM2500 Dual Envelope Generator Module 1003 VM2500 Oscillator Module 1004-P VM2500 Oscillator Module 1004-R VM2500 Oscillator Module 1004-T VM2500 Modamp Module 1005 VM2500 Filtamp Module 1006 VM2500 Dual Noise/Random Voltage Generator Module 1016 VM2500 Oscilloscope Module 1019 VM2500 Dual Oscillator Module 1023 VM2500 Dual Reverberator Module 1025 VM2500 Preset Voltage Module 1026 VM2500 Clocked Sequential Control Module 1027 VM2500 Dual Envelope Generator Module 1033 VM2500 Sample & Hold Module 1036 VM2500 Triple VCA Module 1042 VM2500 Synthesizer Voice Module 1045 VM2500 Quad Envelope Generator Module 1046 VM2500 Multimode Filter Resonator Module 1047 VM2500 Mix-Sequencer Module 1050 VM2500 Dual Four-Channel Mixer Module 1051 VM901 Voltage Controlled Oscillator VM902 Amplifier VM903 Random Signal Generator VM905 Reverb VM907A Fixed Filter Bank VM911-A Dual Trigger Delay VM912 Envelope Follower VM921 Voltage Controlled Oscillator VM923 Filters/Noise VM927 Multiple VM958 Keyboard/VCO Interface VM960 Sequencer VM962 Sequential Switch VM984 Four-Channel Matrix Mixer VM995 Attenuators VM914 Fixed Filter Bank VM928 Sample Hold VM1630 Frequency Shifter VM901ABBB Voltage Controlled Oscillator VM904A/B/C Filters VM911 Envelope Generator VM921ABBB Oscillator Bank VM Rackmode 10 Band Graphic EQ VM Rackmode 12 Stage Phaser VM Rackmode 3 Band Parametric EQ VM Rackmode Poly Vocal Source Oscillator VM Rackmode Ring Modulator VM Rackmode String Filter VM Rackmode Vocal Source Oscillator VM Rackmode Frequency Shifter VM Rackmode 16 Channel Vocoder VM Miniverse A-440 VM Miniverse Contour VM Miniverse Filter VM Miniverse Glide VM Miniverse Mixer VM Miniverse Noise VM Miniverse Oscillator VM Miniverse Poly Contour VM Miniverse Poly Filter VM Miniverse Poly Glide VM Miniverse Poly Mixer VM Miniverse Poly Oscillator VM Miniverse Poly VCA VM Miniverse VCA

The VM912 Envelope Follower outputs a dynamically changing voltage that follows the amplitude of an incoming signal, either from within Voltage Modular, or from an external audio source, via Voltage Modular's sidechain in and IO Panel Audio Sources jacks. (See Audio Sources in the IO Panel section of the Voltage Modular user guide for more information about using sidechain inputs).

This is a great tool for creating dynamic CV signals that can be used to modulate just about anything in Voltage Modular. A drum loop, for example, could be used to modulate the cutoff frequency of a filter, the pitch or pulse-width of an oscillator, etc.

Input, Output, and Controls

Response Time- Sets how fast the follower circuit responds to incoming signals, from 0.01 to 0.1 seconds. Low-frequency input signals generally require the longer response times and vice-versa with high-frequency input signals. 

Threshold- Adjusts the voltage level necessary to output a 5V gate signal at the Gate Out jack.

Signal Input jack- Input jack for the AC audio signal that will be converted to a CV output.

Control Output- Output for the dynamically changing DC voltage derived from the input signal.

Of note is that the original 912 envelope follower is unique among all other envelope followers in that the output is in dB, which is essentially the log of the amplitude instead of the amplitude itself. This is huge, as in really huge. In all other envelope followers, the output is linearly proportional to amplitude, but that’s not how the human ear perceives sound, hence the superiority of the 912 design. It should go without saying that the VM912 module accurately recreates the response of the original.

Control Input- This input expects a positive control signal similar to what is output by the follower. It is then sent to a voltage comparator which compares this signal with the Threshold setting. If the signal is greater than the Threshold, 5V is output at the Gate Output jack. A slight amount of hysteresis is applied to keep the Gate Output from chattering. A useful application for this section alone might be the deriving of a gate signal from an LFO anywhere in its phase, or anything else a voltage comparator might be useful for.

If nothing is plugged into the Control Input jack, the Control Output signal is normalled, as indicated by the dotted line. This allows one signal to provide a dynamically changing DC voltage at the Control Output jack, as well as a +5V gate signal at the Gate Output jack.