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 Cherry Audio VM Rackmode String Filter comprises 36 high-Q parallel bandpass filters arrayed throughout the musical range (say that five times fast... go ahead, we'll wait). The original unit was intended to mimic the multiple static resonances of a stringed instrument body such as the violin or cello. When simple waveforms (especially solo waveforms) are played through it, the String Filter imparts a woody richness to the sound making it sound more "stringlistic."

Having so many resonant filters close together has a secondary effect on the amplitude of moving harmonics as well. If vibrato is applied (i.e., frequency modulation), some harmonics will ride up and down their nearby filter slopes creating amplitude modulation of that harmonic. It is this kind of detail that the unit was created for, but it can create interesting effects from many signal sources.

The adjustment of this mix has a profound effect on the resulting tone. The filters are arranged into odd and even interleaving sets which are associated with the left and right stereo outputs. The stark stereo spread of the odd/even splitting can be lessened by setting the Width control more toward Mono. Note that the String Filter is really useful for stereoizing mono sources!

Input jacks- Plug incoming signals in here. The signal(s) will be routed to filters differently depending upon left and right input routing as follows:

  • L (mono) in - L and R out results in the L audio going through all filters coming out in odd/even stereo.

  • L and R input and outputs- L audio goes through odd and R audio goes through even filters coming out in stereo.

  • L (mono) in, L and R out- L audio goes through all filters coming out in odd/even stereo. (This is great for stereoizing a mono signal.)

  • L (mono) and L (mono) out- L audio goes through all filters and outputs all filters in mono. The individual outputs are monauralized versions of the filter groups.

Frequency and Resonance Offset and Mod

Frequency Mod jack and attenuator- Allows positive or negative CV mod of the Frequency Offset control (see below).

Frequency Offset- The filter frequencies of the original unit were fixed, but we've added a Frequency Offset knob that simultaneously adjusts the frequencies of all 36 filters in parallel.

Resonance Mod jack and attenuator- Allows positive or negative CV mod of the Frequency Offset control (see below).

Resonance Offset- Globally adjusts the bandwidth of all 36 filters. Turning this down all the way pretty much renders the effect inaudible (not at all stringy), and turning it up all the way will sound clangy and metallic.

Frequency Group Controls

Lo/Lo-Mid/Hi-Mid/Hi filter levels- The 36 filters are divided into four groups of nine: Lo, Lo-Mid, Hi-Mid, and Hi. The four groups are mixed via their respective level controls. The adjustment of this mix has a profound effect on the resulting tone.

Frequency Band mod jacks and attenuators- Allows positive or negative CV mod of each frequency group control.

Individual Frequency Group Outputs

Each of the four frequency groups has an individual out. These can be routed for further individual processing.

Output Section

Width- Sets the stereo panning width of the filters.

Output jacks and meters- The output signal(s) of the String Filter. The stereo output meters display nominal level, you know the drill here!