Limaflo - Motomouth


Eurorack Coded CV Sedra+Espinoza Morphing Formant Filter


Motomouth is an analogue 3-Band, Sedra + Espinoza Bandpass Filter (DABP) with resonant frequencies that are tuned to the same resonant frequencies found in the human mouth and nose cavities, and these can be varied, independently, to form different 'mouth shapes', to emulate vowels such as A, E, I, O and U. Motomouth can emulate 16 vowels and 'morph' or 'glide' between each vowel using a single Control Voltage input (1V/Oct), and a Gate to 'snap' to each vowel when required.

Two of the bands (F1 and F2) are used to form the mouth cavity, and the third band (F3) is used to from the nasal cavity, which is reasonably static. Varying F3 makes little significant difference 'in the mix', but having it is important.

The single Control Voltage is decoded to control F1 and F2 independently, because the frequency bands for each vowel are not proportional to each other over the vowel range. So Motomouth has learned how to 'speak', so to speak, but it still needs to learn more, and that's were you come in.

KEY Features

Single CV to control and set vowel shapes.
Automatic Morphing and morphing rates to each vowel.
Gate operated snap to each vowel when required.
Sedra+Espinoza Analogue Filter design for a high, sharp Q value and a 12 dB/octave roll-off slope.
Plays well from a monophonic keyboard or Midi Keyboard through a Midi to CV/Gate converter.
Works great with a CV Step Sequencer.
Filter and vowel mode selection using the same single CV input.
The system is managed by two ATMEGA328P Microcontrollers.
Motomouth is a Monophonic processor. Stereo can be achieved by double tracking or by using two Motomouth modules.


42mm from base of front plate to tip of underside power connection pins (good for most skiffs).
60.5mm (12 HP).
128.5 mm (Doepfer standard).
2mm thick, Aluminium finish.
Silk Screen:
Power connection:
10-pin Header with +12, -12 and 0 Volt connections (Doepfer standard: 10-pin cable, with Red flash on -12V side).
+12V, 70mA max (0.72W).
CV Input range:
0 Volts to +1.25 Volts at 1V/octave scaling for Vowel 1 to Vowel 16.
+/- 15V DC tolerant of any damage.
0V = Off, Typically 5V = On (+0.7V to +12V = On).
+/- 15V DC tolerant.
Input sensitivity:
Up to 10 Vp-p.
10V p-p max (depending on resonance).
3 x classic Sedra & Espinoza Dual Amplifier Bandpass Filters with Q's set to between 5 and 25 and F set to between 200Hz to 3,000Hz.
Resonance wave resolution:
Monophonic, 3.5mm Jack.
CV and Gate Jacks:
One ATMega Microcontroller for decoding and general I/O work, and one ATMega Microcontroller, clocked at 20 MHz, for indirect filter control.
System operational Voltage:
5 VDC, Linear Regulated. +/- 12VDC for the output amplifier.
​NOT SUPPLIED - these will be selected in accordance with which rack system you have. Doepfer do a nice range.

  • 70 mA +12V
  • 30 mA -12V
  • ? mA 5V
  • 42 mm deep
  • Ø 4.33 (3 Votes) Average Rating

This Module is currently available.

12 HP EffectFilter
submitted Mar 4th 2017, 08:51 by acgenerator | last Change Jun 21st, 19:19 by mt3

12 Users are observing this

Buy Online

These merchants probably sell this module. Huh?


ControlBig City MusicPerfect Circuit AudioDetroit ModularControl Voltage