Download Print this page

twisted electrons MegaFM User Manual

Hide thumbs


Quick Links

June 2nd 2020
We always value feedback and ideas, so feel free to reach out.
Please check the website for the latest firmware!
Thank-you for adopting MEGAfm, the product of several years of work &
play. We are particularly fond of the YM2612 as they offer a unique gritty
texture that is uncommon in the FM word, plus hands-on FM experience
that is unprecedented in the hardware FM synthesiser world.
We hope that you will enjoy making music with MEGAfm as much as we
have enjoyed and continue to enjoy developing it!



  Summary of Contents for twisted electrons MegaFM

  • Page 1 FM word, plus hands-on FM experience that is unprecedented in the hardware FM synthesiser world. We hope that you will enjoy making music with MEGAfm as much as we have enjoyed and continue to enjoy developing it!
  • Page 2 YM2612 Overview “The Yamaha 2612 Frequency Modulation (FM) sound synthesis IC resembles the Yamaha 2151 (used in Sega’s coin-op machines) and the chips used in Yamaha’s synthesisers. It is famously known as the Sega Megadrive’s voice. An FM channel is capable of expressing, with a high degree of realism, a single note in almost any instrument’s voice.
  • Page 3 Operators There are four dedicated operators per voice which may be arranged in eight different configurations, called “algorithms”. Following is a diagram of the algorithms. Slots are indicated by shading.     Envelope Specification...
  • Page 4 The sound starts when the key is depressed, a process called ‘key on’. The sound has an attack, a strong primary decay, followed by a slow secondary decay. The sound continues this secondary decay until the key is released, a process called ‘key off’. The sound then begins a rapid final decay, representing for example a piano note after the key has been released and the damper has come down on the strings.
  • Page 5 Voicing MEGAfm offers up to 12 voice polyphony.  The 12 voices are spread across two YM2612 chips. In all modes you can use the fat knob to detune the voices. Hold voicing mode button and the fat knob becomes glide.
  • Page 6 Dual ch3 YM2612 offers a special mode where the 4 operators of channel3 can be individually detuned to arbitrary frequencies as described above in the YM2612 Overview. Recommended for experimental / percussive sounds. Unison All voices are played at once in unison and detuned using the fat knob. Turn the fat knob clockwise to gradually detune all 12 voices.
  • Page 7 Note: both parameters can be modulated by LFO! Vibrato Use the depth knob to add vibrato to the overall pitch of MEGAfm. Use the vibrato rate knob to set the vibrato’s speed. The vibrato can be configured to sync to incoming MIDI clock at 8...
  • Page 8 Arpeggiator and Sequencer When unison voice mode is active the arpeggiator can be used. The arpeggiator has 7 modes: Up (shown as “UP” on the numeric display) Down (shown as “dn” on the numeric display) Up/Down aka pendulum (shown as “Ud” on the numeric display) Random1 (shown as “r1”...
  • Page 9 Recording a sequence To record a sequence press rec to activate recording mode. The rec LED will flash. Now play up to 16 notes via MIDI. Each preset can store up to 16 notes. Every time you input a note, the step recorder will advance and the numeric display will show the current step.
  • Page 10 Modulators ( Lfo 1 to 3) Any knob or fader can be modulated by up to 3 lfo modulators at once. To link a knob or fader to an lfo move a knob or fader and press a chain link button. Click the chain button a second time to unlink a knob or fader from an lfo.
  • Page 11 Selecting an lfo waveform To select any of the 3 LFOs simply move one of the LFO rate or depth knobs.   Use the 4 waveform buttons to select a waveform. Selecting an already lit waveform will put the LFO in manual mode. Now you can adjust the value of the LFO at any time with its depth knob LFO depth Set the depth of an LFO with its depth knob.
  • Page 12 Presets MEGAfm has 600 a preset memory capacity arranged in six banks of 100 presets. MEGAfm currently ships with 50 factory presets (0-49) organised according to the following chart. Misc Bass 10-19 Lead 20-29 Pads 30-38 Rhythmic 39-44 45-49 Each preset can be edited and stored and preset banks can be transferred to and from a computer via MIDI SYSEX.
  • Page 13 0. The numeric display will indicate “P0” for preset zero. Press reset a second time and MEGAfm will read all the faders and knobs as they are set on the control panel. The numeric display will indicate “PA”...
  • Page 14 Setup Mode Hold voicing at startup or anytime for 3 seconds to enter setup mode. “SE” appears on the numeric display Here are the things that can be set: LFO1 to 3 sync to incoming MIDI clock Turn the respective LFO rate knob to choose whether to link LFO1,2 or 3 to the MIDI clock. ...
  • Page 15 Turn the vibrato rate knob to choose whether to link the vibrato to the MIDI clock.  Above 12 o clock the setting is on, below the setting is off. The setting is indicated by ON/OF on the numeric display Velocity controls LFO1 Turn the vibrato depth knob to choose whether to control lfo1 with MIDI velocity.
  • Page 16 By default this setting is OFF. Midi Channel ,Pitch bend up & down Learn In setup mode you can set the input channel simply by sending MEGAfm a NOTE ON message on any midi channel. When a new Midi channel is registered, it is displayed on the numeric display after the letters “Ch”...
  • Page 17 Press arp mode button to toggle this special mode on or off. When the LED is on, MEGAfm is in normal single channel mode, when LED is off MPE mode is active. When you choose MPE mode, the pitch bend range is set to +/-48semi by default, you are free to change it before exiting setup.
  • Page 18: Midi Implementation

    MIDI Implementation MEGAfm responds to the following MIDI controls. You can also control it with the Plugin (available for free download on the website) which uses the following MIDI parameters. Parameter Parameter MIDI CC Range GLOBAL FM Algorithm Feedback 0-127...
  • Page 19 Parameter MIDI CC Range Op2 Sustain Level 0-127 Op2 Sustain Rate 0-127 Op2 Release Rate 0-127 OPERATOR 3 Op3 Detune 0-127 Op3 Multiplier 0-127 Op3 Total Level 0-127 Op3 Attack Rate 0-127 Op3 Decay Rate 0-127 Op3 Sustain Level 0-127 Op3 Sustain Rate 0-127 Op3 Release Rate...
  • Page 20: Firmware Update

    When ready press preset DOWN again to send the presets. MEGAfm will reboot when finished. To upload a half bank to MEGAfm from a computer hold preset UP at startup. Then choose a BANK using the 6 LFO waveform buttons. Press the BANK button again to toggle between A (first half / presets 0-49) or B (second half / presets 50-99).
  • Page 21 Hold Arp MODE at startup. This will put MEGAfm in update mode with all LEDS on. Now transfer the SYSEX file with recommended software via a MIDI interface. The LEDS will blink during the transfer, and MEGAfm will reboot when complete.