sqsl Circle app for iPhone and iPad

Geometry-based semi-generative MIDI sequencer/controller.

Concept:
Place triggers on 2-dimensional ”timeplane” (as opposed to triggers placed on linear 1-dimensional timeline in normal sequencers).
Place playhead - circular wave expanding through timeplane (as opposed to point-playhead advancing on timeline).
When playhead encouters trigger, note is generated.

Rotate timeplane but keep playhead’s origin static - pattern evolves.

Interface: select mode on left side and right side or central part will show options/parameters available. Swipe from left/right edge to hide controls (display only geometry). Swipe again to show controls.

PLAY (playhead)
- Reach (how far playhead will propagate)
- Length (multiplier for note length)
- Octave transposition
- Divider (affecting speed/rate of playhead’s propagation)
- Channel (midi channel to which resulting notes are sent)

When more that one option is enabled for above parameters, playhead randomly chooses one of them on start (reach, octave, divider) or when it encounters trigger (length, channel).

- Rate (playheads propagation speed)
- Loop mode is activated by long touch when placing playhead

NOTE (triggers)
- Type I-VII (each type can have a specific pitch assigned)
- Type T (immediately restarts playhead that reached it)
- Note length
- Select type before placing trigger or use ADVANCE to automatically select next type after placement (type T excluded)
- Velocity is calculated based on triggers distance from playhead

EDIT
- Reposition existing playheads or triggers (touch and drag)
- Select playhead or trigger and edit its parameters

MUTE
- Mute/unmute individual triggers
- Unmute all triggers
- Ignore T triggers

ROOT
- Pitch origin from which type I and all the following types are calculated (transposes all types when changed)

PITCH
- Interval distance from root (for type I) or interval distance from previous type (in octaves and semitones)
- Separate set of 3 columns to set the octave (left) and semitone (right) distance
- First column represents +1 values, second +2 and third +4 (resulting interval is sum of activated columns)
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SPIN
- Set angle directly
- Set rotation speed

MIDI
- Select current MIDI output

WRITE & READ
- Write current state for later recall
- Optionally read only pitch settings (root and pitch table) or only geometry (triggers and playheads) from presets
- Tap on WRITE when write is already active to enter ERASE mode

Detailed description: https://www.seqsual.com/circle
Questions and feedback: https://www.seqsual.com/contact

Important notes:
- Circle does not make any sounds on its own, it generates MIDI messages (notes).
- Circle was designed for full-size iPads, not recommended to use on iPad Mini.