Veteran German developer VirSyn are known primarily for their Mac/PC plugins, but they've also been keeping themselves busy on the App Store of late with touchscreen virtual instruments and effects such as iVoxel, Cube Synth and Addictive Synth. Tera Synth, looks to be their most flexible, powerful iPad synthesiser yet, built on a semi-modular design that takes in both analogue-style and digital sound generating techniques.
Boasting 25 sound-generating and modulation modules that can be interconnected in whatever way the user sees fit, Tera Synth presents its many controls via a flat, grey interface that puts clarity well ahead of visual wow factor.
The 25 modules comprise three basic oscillators (incorporating FM and phase modulation), WaveGuide (a physical modelling device), Ringmodulator, Noise Generator, Subharmonic Oscillator, two analogue filters, Formant Filter, Amplifier, four LFOs, four ADSR envelopes, four multi-segment envelopes (with up to 64 time/level segments each), Keyboard (tuning, portamento, etc) and a 32-step Arpeggiator/step sequencer with randomise function. There are also five effects on tap: a chorus, an 8-pole Phaser, tube/tape Distortion, stereo delay and reverb.
To get you started (and then some), over 900 presets are included, and Tera Synth supports most of the iOS niceties that we've come to expect from any serious music app these days: audio recording, AudioBus, Inter-App Audio, AudioCopy/Paste, SoundCloud upload, CoreMIDI and virtual MIDI.