FAC Envolver, developed by Frederic Corvest, is a full version multimedia software available on the iPhone. As a MIDI effect, it allows users to control their synthesizer parameters using MIDI CC and notes. But what sets FAC Envolver apart is its ability to transform audio through two exclusive effects: a Noise Gate and a Trance Gate.

The envelope follower in FAC Envolver generates MIDI data based on the contour of a signal. This signal can come from either a classic envelope follower circuit or a rhythmic pattern called a trigger gate. The signal envelope can be modified using various parameters and delivered as MIDI control change messages (CC). Additionally, a gate detection mechanism driven by a threshold creates a second envelope that is delivered as MIDI CC and notes.

In addition to MIDI effects, FAC Envolver includes a noise gate that allows precise control over the audio signal level. This gate, based on the same open/close sequence as the MIDI gate, acts on the audio itself. Engaging the trigger gate circuit adds a trance gate effect to the audio, further enhancing its versatility.

FAC Envolver is a stereo effect with two slots, one for each channel. These slots can be linked for easier manipulation. The software also supports mono audio and allows users to mix the dry and wet audio signals.

With its comprehensive set of features and powerful audio transformations, FAC Envolver is a must-have tool for musicians and sound designers looking to add dynamic modulation and sequences to their sound.