ZynAddSubFX is a opensource software synthesizer capable of making a countless number of instruments, from some common heared from expensive hardware to interesting sounds that youll boost to an amazing universe of sounds.
Features:
realtime synthesizer
polyphonic (allows playing more than one note at once), mutlitimbral (allows playing more than one instrument at once) synth
Microtonal capabilities with any scale, any number of notes per octave (well... the no. of notes per octave must be less than 128) and keymapping
2 synthesiser engines:
first (called "ADsynth" or "ADnote") is a complex engine which makes sounds by adding a number of voices. Each one has filters, envelopes, LFOs, morphing, modulation (Ring Modulation, Phase Modulation... the modulators can have any shape), resonance, etc. Each voice includes a very powerful waveform generator with up to 128 sine/nonsine harmonics. You can use Fourier synthesis or if you dont like it you can waveshaping/filtering of functions. This engine includes antialiasing.
second (called "SUBsynth" or "SUBnote") is a simpler engine who allows to make sounds by subtraction of harmonics of sounds from white noise
Instruments can be orgainzed in kits, which alows you to make drum kits or layered(mixed) instruments; this makes possible to use more than one instrument for a single part. It is possible to choose what items from the kit should be processed by the Parts effects.
Effects: Reverb, Echo, Chorus/Flange, Phaser,AlienWah (its a kind of vocal morpher), Distorsion(Waveshaping) and EQ
The effects can behave as System Effects or as Insertion Effects; this allows to use many effects at the same time. You can put any insertion effect on any part(or more insertion effects to same parts, if you like so) or you can put the insertion effect to Master output (very usefull if you use the EQ effect). Also, you can have instruments effect (that is saved with the instrument).
Filters up to 60dB/octave (or more..); filters can be analogic (LPF,HPF, BPF,etc.) or formant
Envelopes can have ADSR (or ASR, etc..) modes or can be free modes (with any shape)
Many settings has a "randomness" option, which you can make instruments that every time produces a subtle different sound; this produces a very pleasent effect (like analogue synths or natural instruments that cant produces exactly same sound twice). Because of this, even if it is digital synthesis, it sounds "warm". Listen the ogg vorbis demos from this page to hear this effect.
the specifications can be easily chaged, so (for example) if you want to change the number of voices or parts to a higher value or to allow a higher number of effects at the same time, there is necessary to chage only a single value from the source file (globals.h) and to recompile the program
Intuitive and easy to use User Interface
Midi support (supports many controllers) and (if you want) JACK support
the program has Virtual Keyboard which let you to use it even if you dont have a real midi keyboard
it is a free program, licensed under version 2 of the GNU General Public License
