>>> MINI VIRTUAL ANALOG SYNTHESIZER

I've spent the past couple months putting together a small synthesizer program. It started out as the very simple synthesizer example program that came with the BASS sound library but has changed almost completely since then.

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Current Release

Release 7 (2015-03-14) Clicktastic

Previous Releases

Release 6 (2015-03-14) Happy Pi Day!
Release 5 (2014-02-14)
Release 4 (2014-01-23)
Release 3 (2014-01-06)
Release 2 (2014-01-01)
Release 1 (2013-12-30)

Source Code

 Now on GitHub!

Controls

• Letter keys play notes
• - and + adjust output volume
• [ and ] shift octaves
• F1 through F9 select menus on the active page
• F10 switches to main page
• F11 switches to effects page
• F12 toggles antialiasing
• Tab and Shift-Tab cycle forward and backwards through menus
• Up and Down arrows move up and down between menu items
• Left and Right arrow on a menu title turns the component off and on
• Left and Right arrows decrease and increase values
  • Hold Shift for large steps: 12 semitone (1 octave) frequency, 1/4 magnitude, or 1 second
  • No modifier for normal steps:1 semitone frequency, 1/16 magnitude, or 0.1 second
  • Hold Ctrl for small steps: 0.1 semitone frequency, 1/64 magnitude, or 0.01 second
  • Holt Alt for tiny steps:0.01 semitone frequency 1/256 magnitude, or 0.001 second
• Left and Right arrow on an ON/OFF value sets it to off and on
• Click on menu titles and entries to select them

Requirements

Windows XP or later

Visual C++ 2013 Redistributable Package (x86)

Features

16-note polyphony

29 note key bindings

• Two full octaves plus five extra notes (ZSXDCVGBHNJM, Q2W3ER5T6Y7U, I9O0P)
• Initially centered on middle C

10-octave range (C0 through C10)

• Key octave sets octave of center note key (Q)

MIDI input

• Full range of MIDI notes
• Key velocity
• Pitch wheel

Variety of waveforms

• Classic analog waveforms
  • sine, pulse, sawtooth, triangle
  • support hard-sync effect
• Noise waveforms
  • colored noise: red, pink, white, blue, violet (selected by width)
  • sample-and-hold noise
  • linearly-interpolated noise
• Linear feedback shift register waveforms
  • poly4, poly5, period-93, poly9, poly17, pulse/poly5, poly4/poly5, poly17/poly5
• Band-limited with PolyBLEP to reduce aliasing

Two sound oscillators per voice

• Use any available waveform
• Frequency offset from note key tunable in octave, semitone, 10 cent, and 1 cent steps
• Modulate pulse width, frequency, and amplitude with LFO
• Hard sync on second oscillator
• Key follow controls how frequency tracks note keys

One shared low-frequency oscillator

• Use any available waveform
• Frequency tunable in octave, semitone, 10 cent, and 1 cent steps

Resonant Filter per voice

• Simulated Moog-style resonant ladder filter
• Based on Will Pirkle's implementation of Vadim Zavalishin's Topology-Preserving Transform (TPT) virtual analog ladder filter
• Analog-style nonlinear saturation
• 25 different filter modes
  • Based on a mixing technique used by Oberheim Xpander and Matrix-12 synthesizers
  • Peak
  • Low-pass: 6 dB/octave, 12 dB/octave, 18 dB/octave, 24 dB/octave
  • High-pass: 6 dB/octave, 12 dB/octave, 18 dB/octave, 24 dB/octave
  • Band-pass: 6 dB/octave, 12 dB/octave
  • Band-stop (notch): 6 dB/octave, 12 dB/octave
  • All-pass (phase shift): 1-pole, 2-pole, 3-pole, 4-pole
  • "Combo" modes with additional low-pass or high-pass filtering
• Cutoff frequency tunable in octave, semitone, 10 cent, and 1 cent steps
• Supports input drive up to 1000%
• Supports resonance effects up to full self-oscillation
• Dedicated ADSR envelope generator
• Attack, Decay, and Release times settable in second, 100 ms, 10 ms, and 1 ms steps
• Modulate cutoff frequency with LFO, envelope, and key velocity
• Key follow controls how cutoff frequency tracks note keys

Amplifier per voice

• Modulate level with envelope and key velocity
• Dedicated ADSR envelope generator
• Attack, Decay, and Release times settable in second, 100 ms, 10 ms, and 1 ms steps

DirectSound effects

• Chorus, Compressior, Distortion, Echo, Flanger, Gargle, I3D Reverb, Waves Reverb
• Fully configurable settings

Note Envelope Display

• Note key indicators show volume envelope state
• Attack in green
• Decay in red
• Sustain in white
• Release in grey

Spectrum Analyzer Display

• One semitone per column
• 6dB power attenuation per row
• Aligned with note key indicators
• Shows audible limit (beginning of purple region)
• Shows Nyquist limit (beginning of red region)

Oscillator Waveform Display

• Shows the waveform generated by the current oscillator, LFO, filter, and volume envelope setting

Voice Activity Display

• Shows amplifier envelope state for each active voice

Processor Usage Display

• CPU time as reported by BASS
• Shows percentage of one CPU core used by sound generation