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6 FILTER

6.1 Description

The MOTOR Synth features a powerful FILTER section with two identical analog multimode filters for each MOTOR VOICE and a digital filter for the DCO. In total three fully featured multimode filters. All three filters share one set of knobs and can be controlled either individually or all together. The digital filter is an emulation of the analog filter circuits and therefore shares the same functionality and parameters. The filter modes are 24 dB Low Pass, 12 dB Band Pass, 12 dB High Pass and 24dB All Pass. There is a DRIVE circuit before each filter as well as an independent FILTER ENVELOPE with variable ENVELOPE AMOUNT. The RESONANCE control can push each filter into self-oscillation and as each filter is calibrated to precisely track pitch, self-resonating filters can be used as oscillators.

Note: The MOTOR Synth signal path before the FILTER is polyphonic where each motor and digital oscillator has a dedicated amplifier controlled by a individual envelope. The FILTER section is paraphonic, where all 4 motors of each MOTOR VOICE and all 4 oscillators of the DIGITAL VOICE are mixed together and passed through one FILTER.

IN THIS SECTION

6.2 List of parameters

All three FILTERS share one set of controls that can either control one of the FILTERS at a time or all FILTERS at the same time. Refer to LINK FUNCTIONALITY for more information. Additional parameters in the FILTER SCREEN are controlled with the LEFT & RIGHT SCREEN ENCODERS. Push the V1 FILTER, V2, FILTER or DCO FILTER buttons to access the FILTER SCREEN of the given voice.
This list contains an overview of all parameters in this section. For further information refer to the Instructions sub-section.  This list does not include FILTER ENVELOPE parameters, because the FILTER ENVELOPES function the same and offer control over the  the same parameters as AMP ENVELOPES.
PARAMETERCONTROLDESCRIPTIONVALUE RANGE
Filer type [TYPE]TYPE knobFilter type selection“LP24” 24dB Low Pass;
“BP12” 12dB Band Pass;
“HP12” 12 dB High Pass;
“AP24” 24 dB All Pass
[CUTOFF]CUTOFF FREQ knob for coarse tuning & ▷ LEFT SCREEN ENCODER for fine tuningThe filter cutoff point in cents (default) or hertz depending on the settings in the SYSTEM MENUFrom 20 to 21096 Hz or from 0 to 12000 cents relative to 20 Hz
Resonance [RES]RESONANCE knob Resonance amountFrom 0 to 100. Self-oscillation starts at ∼87
[DRIVE]DRIVE knobDrive circuit gain before the FILTERFrom 0 (unity gain) to 100 (maximum distortion)
Envelope Amount [ENV AMT]FILTER ENV AMOUNT knobThe amount of FILTER ENVELOPE modulation on [CUTOFF]From -100 (Full amount, inverted), through 0, to 100 (full amount)
Key Tracking [KYTR]◁ RIGHT SCREEN ENCODER[CUTOFF] key tracking status“OFF”; “ON”
Key Tracking Amount [AMT]◁ RIGHT SCREEN ENCODERThe key tracking amountFrom -100 (Inverted tracking) through 0 to 100 (precise tracking)
Key Tracking Glide [GLIDE]◁ RIGHT SCREEN ENCODERKey tracking gilde (slew / portamento)From 0 to 5
PARAMETERCONTROLDESCRIPTIONVALUE RANGE
Filer type [TYPE]TYPE knobFilter type selection“LP24” 24dB Low Pass;
“BP12” 12dB Band Pass;
“HP12” 12 dB High Pass;
“AP24” 24 dB All Pass
[CUTOFF]CUTOFF FREQ knob for coarse tuning & ▷ LEFT SCREEN ENCODER for fine tuningThe filter cutoff point in cents (default) or hertz depending on the settings in the SYSTEM MENUFrom 20 to 21096 Hz or from 0 to 12000 cents relative to 20 Hz
Resonance [RES]RESONANCE knob Resonance amountFrom 0 to 100. Self-oscillation starts at ∼87
[DRIVE]DRIVE knobDrive circuit gain before the FILTERFrom 0 (unity gain) to 100 (maximum distortion)
Envelope Amount [ENV AMT]FILTER ENV AMOUNT knobThe amount of FILTER ENVELOPE modulation on [CUTOFF]From -100 (Full amount, inverted), through 0, to 100 (full amount)
Key Tracking [KYTR]◁ RIGHT SCREEN ENCODER[CUTOFF] key tracking status“OFF”; “ON”
Key Tracking Amount [AMT]◁ RIGHT SCREEN ENCODERThe key tracking amountFrom -100 (Inverted tracking) through 0 to 100 (precise tracking)
Key Tracking Glide [GLIDE]◁ RIGHT SCREEN ENCODERKey tracking gilde (slew / portamento)From 0 to 5
Filter type [TYPE]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

Filer type [TYPE]

TYPE knob

Filter type selection

“LP24” 24dB Low Pass;
“BP12” 12dB Band Pass;
“HP12” 12 dB High Pass;
“AP24” 24 dB All Pass

[CUTOFF]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

[CUTOFF]

CUTOFF FREQ knob for coarse tuning &  LEFT SCREEN ENCODER for fine tuning

The filter cutoff point in cents (default) or hertz depending on the settings in the SYSTEM MENU

From 20 to 21096 Hz
or
From 0 to 12000 cents relative to 20 Hz

Resonance [RES]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

Resonance [RES]

RESONANCE knob

Resonance amount

From 0 to 100.
Self-oscillation starts at ∼87

[DRIVE]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

[DRIVE]

DRIVE knob

Drive circuit gain before the FILTER

From 0 (unity gain) to 100 (maximum distortion)

Envelope Amount [ENV AMNT]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

Envelope Amount [ENV AMT]

FILTER ENV AMOUNT knob

The amount of FILTER ENVELOPE modulation on [CUTOFF]

From -100 (Full amount, inverted), through 0, to 100 (full amount)

Key Tracking [KYTR]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

Key Tracking [KYTR]

 RIGHT SCREEN ENCODER

[CUTOFF] key tracking status

“OFF”; “ON”

Key Tracking Amount [AMNT]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

Key Tracking Amount [AMT]

 RIGHT SCREEN ENCODER

The key tracking amount

From -100 (Inverted tracking) through 0 to 100 (precise tracking)

Key Tracking Glide [GLIDE]
PARAMETER CONTROL DESCRIPTION VALUE RANGE

Key Tracking Glide [GLIDE]

 RIGHT SCREEN ENCODER

Key tracking gilde (slew / portamento)

From 0 to 5

6.3 Instructions

6.3.1 Entering and navigating the FILTER SCREEN

Push V1 FILTER, V2 FILTER or DCO FILTER buttons to enter the FILTER SCREEN of the corresponding voice.

Once the FILTER SCREEN is active it is possible to toggle between the voices by using  the < > buttons in the bottom left corner of the MOTOR Synth. This navigation option is suggested by the small arrow symbols [< >] at the top of the FILTER SCREEN.

6.3.2 Setting the basic FILTER parameters [TYPE], [CUTOFF], Resonance [RES] and [DRIVE].

Turn the TYPE rotary switch to choose one of four Filter Types [TYPE] – 24 dB Low Pass, 12 dB Band Pass, 12dB High Pass and 24 dB All Pass. All four filter types are resonant and can self-oscillate including the All Pass filter. Turn the CUTOFF FREQ knob to set the Filter Cutoff Frequency [CUTOFF]. This knob functions as a coarse tune control and is fully sufficient in most cases. If a fine-tune control is required to set a very precise cutoff frequency turn the  LEFT SCREEN ENCODER while in the FILTER SCREEN.

Note: The FILTER Cutoff Frequency [CUTOFF] ranges from 20 to 21096 Hz. However, the default [CUTOFF] measurement unit is cents where 0 cents correspond to a frequency of 20 Hz or roughly E0 note. The measurement unit (hertz or cents) can be changed in the SETTINGS MENU. Using cents as a measurement unit is useful when utilizing the Keytrackng [KYTR]. Cents indicate the [CUTOFF] offset from the note pitch. For example, if Keytrack Amount [AMT] is set to 100 then setting the [CUTOFF] to 1200c will correspond to one octave above note pitch.

Turn the RESONANCE knob to set the Filter Resonance [RES] amount. Self-oscillation starts around value 87, but the effect depends on other parameters, like [CUTOFF] and [DRIVE].

Turn the DRIVE knob to set the [DRIVE] level. This will raise the output level of the VOICE, distort the signal  and add more harmonic content before filtering.

Tip: Other instruments that utilize electromagnetic induction pickups, especially the electric guitar, are known to be used with distortion and filtering afterwards. In the case of the electric guitar, pedals and amplifiers introduce distortion that is filtered by guitar speakers. Similarly the harmonically rich motor electromagnetic induction sound responds well to distortion and filtering.

6.3.3 Setting the FILTER ENVELOPE and Envelope Amount [ENV AMT]

Each of the three FILTERS has a dedicated FILTER ENVELOPE which modulates the respective filter’s  [CUTOFF] parameter. The ENVELOPE Shape can be adjusted  with the FILTER ENV / CURVE encoder. The ENVELOPE  functions the same as the AMP ENVELOPE. Please refer to the AMP ENVELOPE section for details.

Turn the FILTER ENV AMOUNT knob to set the Envelope Amount [ENV AMT] for the [CUTOFF] parameter.
As the ENVELOPE AMOUNT Knob is a center indent potentiometer,  it offers gradual positive and negative modulation amounts. In the center indent position the [ENV AMT] is zero.

6.3.4 Using Key Tracking [KYTR]

The MOTOR Synth FILTERS are calibrated to precisely track pitch. The Key Tracking [KYTR] and related parameters determine how the FILTER tracks pitch. The FILTER will track the pitch of the last note played for the given voice.

Turn the  RIGHT SCREEN ENCODER to toggle the [KYTR] between the “OFF” and “ON” states.

Push the  RIGHT SCREEN ENCODER to highlight  the Key Tracking Amount [AMT] parameter and turn the encoder to change the parameter’s value. The default value is 0 which produces no key tracking. The maximum value 100 provides precise key tracking. The minimum value -100 produces inverted key tracking. 

Key Tracking [KYTR] modulates the [CUTOFF] parameter. In order for the [CUTOFF] frequency to match the note frequency, set the CUTOFF knob to the minimum position value 0c or 20 Hz and then set the Key Tracking Amount [AMT] to 100.

Tip: Even though setting [KYTR] to the ''OFF" position produces the same effect as setting the amount [AMT] to 0, the [KYTR] parameter can be quickly and easily toggled during a performance, while the [AMT] parameter remains set to a specific value. This can be very useful when performing with a self-oscillating FILTER that is being toggled between Keytracking and non-Keytracking modes.

Push and then turn the  RIGHT SCREEN ENCODER to set the Key Tracking Glide [GLIDE] – an innovative parameter which adds  slew (portamento) to the FILTER Key Tracking function.

Tip: Because the FILTER is paraphonic, long Key Tracking Glide [GLIDE] values can be very useful when performing long polyphonic pads or ambiences. Without the [GLIDE}, whenever a new note is layered, the FILTER [CUTOFF] will suddenly change, thus causing the already playing notes to change their sound. Longer Key Tracking Glide [GLIDE] values help smooth out this unwanted effect.

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